View Source erl_syntax (syntax_tools v3.2.1)
Abstract Erlang syntax trees.
This module defines an abstract data type for representing Erlang source code as
syntax trees, in a way that is backwards compatible with the data structures
created by the Erlang standard library parser module erl_parse (often referred
to as "parse trees", which is a bit of a misnomer). This means that all
erl_parse trees are valid abstract syntax trees, but the reverse is not true:
abstract syntax trees can in general not be used as input to functions expecting
an erl_parse tree. However, as long as an abstract syntax tree represents a
correct Erlang program, the function revert/1 should be able to transform it
to the corresponding erl_parse representation.
A recommended starting point for the first-time user is the documentation of the
syntaxTree() data type, and the function type/1.
Note
This module deals with the composition and decomposition of syntactic entities (as opposed to semantic ones); its purpose is to hide all direct references to the data structures used to represent these entities. With few exceptions, the functions in this module perform no semantic interpretation of their inputs, and in general, the user is assumed to pass type-correct arguments — if this is not done, the effects are not defined.
With the exception of the erl_parse() data structures, the
internal representations of abstract syntax trees are subject to change without
notice, and should not be documented outside this module. Furthermore, we do not
give any guarantees on how an abstract syntax tree may or may not be
represented, with the following exceptions: no syntax tree is represented by a
single atom, such as none, by a list constructor [X | Y], or by the empty
list []. This can be relied on when writing functions that operate on syntax
trees.
Summary
Functions
Creates an abstract empty list.
Returns the syntax tree corresponding to an Erlang term.
Appends the term Annotation to the list of user annotations of Node.
Appends Comments to the post-comments of Node.
Appends Comments to the pre-comments of Node.
Creates an abstract annotated type expression.
Returns the type subtrees of an annotated_type node.
Returns the name subtree of an annotated_type node.
Creates an abstract function application expression.
Creates an abstract function application expression.
Returns the list of argument subtrees of an application node.
Returns the operator subtree of an application node.
Creates an abstract arity qualifier.
Returns the argument (the arity) subtree of an arity_qualifier node.
Returns the body subtree of an arity_qualifier node.
Creates an abstract atom literal.
Returns the literal string represented by an atom node.
Returns the literal string represented by an atom node.
Returns the printname of an atom node.
Returns the value represented by an atom node.
Equivalent to attribute(Name, none).
Creates an abstract program attribute.
Returns the list of argument subtrees of an attribute node, if any.
Returns the name subtree of an attribute node.
Creates an abstract binary-object template.
Creates an abstract binary comprehension.
Returns the list of body subtrees of a binary_comp node.
Returns the template subtree of a binary_comp node.
Equivalent to binary_field(Body, []).
Creates an abstract binary template field.
Creates an abstract binary template field.
Returns the body subtree of a binary_field.
Returns the size specifier subtree of a binary_field node, if any.
Returns the list of type-specifier subtrees of a binary_field node.
Returns the list of field subtrees of a binary node.
Creates an abstract binary_generator.
Returns the body subtree of a generator node.
Returns the pattern subtree of a generator node.
Creates an abstract bitstring type.
Returns the number of start bits, M, of a bitstring_type node.
Returns the segment size, N, of a bitstring_type node.
Creates an abstract block expression.
Returns the list of body subtrees of a block_expr node.
Creates an abstract case-expression.
Returns the argument subtree of a case_expr node.
Returns the list of clause subtrees of a case_expr node.
Creates an abstract catch-expression.
Returns the body subtree of a catch_expr node.
Creates an abstract character literal.
Returns the literal string represented by a char node.
Returns the literal string represented by a char node.
Returns the value represented by a char node.
Creates an abstract class qualifier.
Creates an abstract class qualifier.
Returns the argument (the class) subtree of a class_qualifier node.
Returns the body subtree of a class_qualifier node.
Returns the stacktrace subtree of a class_qualifier node.
Equivalent to clause([], Guard, Body).
Creates an abstract clause.
Return the list of body subtrees of a clause node.
Returns the guard subtree of a clause node, if any.
Returns the list of pattern subtrees of a clause node.
Equivalent to comment(none, Strings).
Creates an abstract comment with the given padding and text.
Returns the amount of padding before the comment, or none.
Returns the lines of text of the abstract comment.
Yields the most compact form for an abstract list skeleton.
Returns the Erlang term represented by a syntax tree.
Creates an abstract conjunction.
Returns the list of body subtrees of a conjunction node.
"Optimizing" list skeleton cons operation.
Creates an abstract constrained function type.
Returns the function constraint subtree of a constrained_function_type node.
Returns the function type subtree of a constrained_function_type node.
Creates an abstract (subtype) constraint.
Returns the name subtree of a constraint node.
Returns the type subtree of a constraint node.
Copies the list of user annotations from Source to Target.
Copies the attributes from Source to Target.
Copies the pre- and postcomments from Source to Target.
Copies the annotation from Source to Target.
For special purposes only. Returns the associated data of a syntax tree node.
Creates an abstract disjunction.
Returns the list of body subtrees of a disjunction node.
Creates an abstract else-expression.
Returns the list of clause subtrees of an else_expr node.
Creates an abstract end-of-file marker.
Creates an abstract error marker.
Returns the ErrorInfo structure of an error_marker node.
Flattens sublists of a form_list node.
Creates an abstract floating-point literal.
Returns the numeral string represented by a float node.
Returns the value represented by a float node.
Creates an abstract sequence of "source code forms".
Returns the list of subnodes of a form_list node.
Creates an abstract fun-expression.
Returns the arity of a fun_expr node.
Returns the list of clause subtrees of a fun_expr node.
Creates an abstract fun of any type.
Creates an abstract function definition.
Returns the arity of a function node.
Returns the list of clause subtrees of a function node.
Returns the name subtree of a function node.
Equivalent to function_type(any_arity, Type).
Creates an abstract function type.
Returns the argument types subtrees of a function_type node.
Returns the return type subtrees of a function_type node.
Creates an abstract list generator.
Returns the body subtree of a generator node.
Returns the pattern subtree of a generator node.
Returns the list of user annotations associated with a syntax tree.
Returns a representation of the attributes associated with a syntax tree node.
Returns the annotation (see //stdlib/erl_anno) associated with
Node.
Returns the associated post-comments of a node.
Returns the associated pre-comments of a node.
Yields false if the node has no associated comments, and true otherwise.
Creates an abstract if-expression.
Returns the list of clause subtrees of an if_expr node.
Creates an abstract "implicit fun" expression.
Creates an abstract "implicit fun" expression.
Creates an abstract module-qualified "implicit fun" expression.
Returns the name subtree of an implicit_fun node.
Creates an abstract infix operator expression.
Returns the left argument subtree of an infix_expr node.
Returns the operator subtree of an infix_expr node.
Returns the right argument subtree of an infix_expr node.
Creates an abstract integer literal.
Returns the numeral string represented by an integer node.
Creates an abstract range type.
Returns the high limit of an integer_range_type node.
Returns the low limit of an integer_range_type node.
Returns the value represented by an integer node.
Returns true if Node has type atom and represents Value, otherwise
false.
Returns true if Node has type char and represents Value, otherwise
false.
Returns true if Node is a syntax tree representing a so-called "source code
form", otherwise false.
Returns true if Node has type integer and represents Value, otherwise
false.
Returns true if Node is a leaf node, otherwise false.
Returns true if Node has type list or nil, otherwise false.
Returns true if Node represents a literal term, otherwise false.
Returns true if Node represents a proper list, and false otherwise.
Returns true if Node has type string and represents Value, otherwise
false.
For special purposes only. Returns true if Tree is an abstract syntax tree
and false otherwise.
Appends the comments of Source to the current comments of Target.
Equivalent to list(List, none).
Constructs an abstract list skeleton.
Creates an abstract list comprehension.
Returns the list of body subtrees of a list_comp node.
Returns the template subtree of a list_comp node.
Returns the list of element subtrees of a list skeleton.
Returns the head element subtree of a list node.
Returns the number of element subtrees of a list skeleton.
Returns the prefix element subtrees of a list node.
Returns the suffix subtree of a list node, if one exists.
Returns the tail of a list node.
Equivalent to macro(Name, none).
Creates an abstract macro application.
Returns the list of argument subtrees of a macro node, if any.
Returns the name subtree of a macro node.
Creates a syntax tree with the given type and subtrees.
Creates an abstract map comprehension.
Returns the list of body subtrees of a map_comp node.
Returns the template subtree of a map_comp node.
Equivalent to map_expr(none, Fields).
Creates an abstract map expression.
Returns the argument subtree of a map_expr node, if any.
Returns the list of field subtrees of a map_expr node.
Creates an abstract map assoc field.
Returns the name subtree of a map_field_assoc node.
Returns the value subtree of a map_field_assoc node.
Creates an abstract map exact field.
Returns the name subtree of a map_field_exact node.
Returns the value subtree of a map_field_exact node.
Creates an abstract map_generator.
Returns the body subtree of a map_generator node.
Returns the pattern subtree of a map_generator node.
Equivalent to map_type(any_size).
Creates an abstract type map.
Creates an abstract map type assoc field.
Returns the name subtree of a map_type_assoc node.
Returns the value subtree of a map_type_assoc node.
Creates an abstract map type exact field.
Returns the name subtree of a map_type_exact node.
Returns the value subtree of a map_type_exact node.
Returns the list of field subtrees of a map_type node.
Creates an abstract match-expression.
Returns the body subtree of a match_expr node.
Returns the pattern subtree of a match_expr node.
Equivalent to maybe_expr(Body, none).
Creates an abstract maybe-expression.
Returns the list of body subtrees of a maybe_expr node.
Returns the else subtree of a maybe_expr node.
Creates an abstract maybe-expression, as used in maybe blocks.
Returns the body subtree of a maybe_expr node.
Returns the pattern subtree of a maybe_expr node.
Creates a meta-representation of a syntax tree.
Creates an abstract module qualifier.
Returns the argument (the module) subtree of a module_qualifier node.
Returns the body subtree of a module_qualifier node.
Creates an abstract named fun-expression.
Returns the arity of a named_fun_expr node.
Returns the list of clause subtrees of a named_fun_expr node.
Returns the name subtree of a named_fun_expr node.
Expands an abstract list skeleton to its most explicit form.
Creates an abstract operator.
Returns the literal string represented by an operator node.
Returns the name of an operator node.
Creates an abstract parenthesised expression.
Returns the body subtree of a parentheses node.
Creates an abstract prefix operator expression.
Returns the argument subtree of a prefix_expr node.
Returns the operator subtree of a prefix_expr node.
Equivalent to receive_expr(Clauses, none, []).
Creates an abstract receive-expression.
Returns the list of action body subtrees of a receive_expr node.
Returns the list of clause subtrees of a receive_expr node.
Returns the timeout subtree of a receive_expr node, if any.
Creates an abstract record field access expression.
Returns the argument subtree of a record_access node.
Returns the field subtree of a record_access node.
Returns the type subtree of a record_access node.
Equivalent to record_expr(none, Type, Fields).
Creates an abstract record expression.
Returns the argument subtree of a record_expr node, if any.
Returns the list of field subtrees of a record_expr node.
Returns the type subtree of a record_expr node.
Equivalent to record_field(Name, none).
Creates an abstract record field specification.
Returns the name subtree of a record_field node.
Returns the value subtree of a record_field node, if any.
Creates an abstract record field index expression. The result represents
"#Type.Field".
Returns the field subtree of a record_index_expr node.
Returns the type subtree of a record_index_expr node.
Creates an abstract record type.
Creates an abstract record type field.
Returns the name subtree of a record_type_field node.
Returns the type subtree of a record_type_field node.
Returns the fields subtree of a record_type node.
Returns the name subtree of a record_type node.
Clears the associated comments of Node.
Returns an erl_parse-compatible representation of a syntax tree, if possible.
Reverts a sequence of Erlang source code forms.
Sets the list of user annotations of Node to Annotations.
Sets the attributes of Node to Attributes.
Sets the position information of Node to Pos.
Sets the post-comments of Node to Comments.
Sets the pre-comments of Node to Comments.
Creates an abstract size qualifier.
Returns the argument subtree (the size) of a size_qualifier node.
Returns the body subtree of a size_qualifier node.
Creates an abstract string literal.
Returns the literal string represented by a string node.
Returns the literal string represented by a string node.
Returns the value represented by a string node.
Returns the grouped list of all subtrees of a syntax tree.
Creates an abstract piece of source code text.
Returns the character sequence represented by a text node.
Equivalent to tree(Type, []).
For special purposes only. Creates an abstract syntax tree node with type tag
Type and associated data Data.
Equivalent to try_expr(Body, [], [], After).
Equivalent to try_expr(Body, [], Handlers).
Creates an abstract try-expression.
Returns the list of "after" subtrees of a try_expr node.
Returns the list of body subtrees of a try_expr node.
Returns the list of case-clause subtrees of a try_expr node. If Node
represents "try Body catch H1; ...; Hn end", the result is the empty
list.
Returns the list of handler-clause subtrees of a try_expr node.
Creates an abstract tuple.
Returns the list of element subtrees of a tuple node.
Returns the number of elements of a tuple node.
Equivalent to tuple_type(any_size).
Creates an abstract type tuple.
Returns the list of type element subtrees of a tuple_type node.
Returns the type tag of Node.
Creates an abstract type application expression.
Creates an abstract type application expression.
Returns the arguments subtrees of a type_application node.
Returns the type name subtree of a type_application node.
Creates an abstract type union.
Returns the list of type subtrees of a type_union node.
Creates an abstract typed record field specification.
Returns the field subtree of a typed_record_field node.
Returns the type subtree of a typed_record_field node.
Creates an abstract universal pattern ("_").
Creates a syntax tree with the same type and attributes as the given tree.
Creates an abstract user type.
Returns the arguments subtrees of a user_type_application node.
Returns the type name subtree of a user_type_application node.
Creates an abstract variable with the given name.
Returns the name of a variable node as a string.
Returns the name of a variable node as an atom.
Creates an abstract warning marker.
Returns the ErrorInfo structure of a warning_marker node.
Types
-type annotation_or_location() :: erl_anno:anno() | erl_anno:location().
-type encoding() :: utf8 | unicode | latin1.
-type erl_parse() :: erl_parse:abstract_clause() | erl_parse:abstract_expr() | erl_parse:abstract_form() | erl_parse:abstract_type() | erl_parse:form_info() | erl_parse:af_binelement(term()) | erl_parse:af_generator() | erl_parse:af_remote_function().
-type forms() :: syntaxTree() | [syntaxTree()].
-type guard() :: none | syntaxTree() | [syntaxTree()] | [[syntaxTree()]].
-type padding() :: none | integer().
-type syntaxTreeAttributes() :: #attr{pos :: term(), ann :: [term()], com :: none | #com{pre :: [syntaxTree()], post :: [syntaxTree()]}}.
-type tree() :: #tree{type :: atom(), attr :: #attr{pos :: term(), ann :: [term()], com :: none | #com{pre :: [syntaxTree()], post :: [syntaxTree()]}}, data :: term()}.
-type wrapper() :: #wrapper{type :: atom(), attr :: #attr{pos :: term(), ann :: [term()], com :: none | #com{pre :: [syntaxTree()], post :: [syntaxTree()]}}, tree :: erl_parse()}.
Functions
-spec nil() -> syntaxTree().
Creates an abstract empty list.
The result represents "[]". The empty list is traditionally called
"nil".
See also: is_list_skeleton/1, list/2.
-spec abstract(term()) -> syntaxTree().
Returns the syntax tree corresponding to an Erlang term.
Term must be a literal term, meaning one that can be represented as a
source code literal. Thus, it must not contain a process identifier,
port, reference, or function value as a subterm. The function
recognises printable strings, in order to get a compact and readable
representation. Evaluation fails with reason badarg if Term is not
a literal term.
See also: concrete/1, is_literal/1.
-spec add_ann(term(), syntaxTree()) -> syntaxTree().
Appends the term Annotation to the list of user annotations of Node.
Note: this is equivalent to
set_ann(Node, [Annotation | get_ann(Node)]), but potentially
more efficient.
-spec add_postcomments([syntaxTree()], syntaxTree()) -> syntaxTree().
Appends Comments to the post-comments of Node.
Note: This is equivalent to
set_postcomments(Node, get_postcomments(Node) ++ Comments),
but potentially more efficient.
See also: add_precomments/2, comment/2, get_postcomments/1,
join_comments/2, set_postcomments/2.
-spec add_precomments([syntaxTree()], syntaxTree()) -> syntaxTree().
Appends Comments to the pre-comments of Node.
Note: This is equivalent to
set_precomments(Node, get_precomments(Node) ++ Comments),
but potentially more efficient.
See also: add_postcomments/2, comment/2, get_precomments/1,
join_comments/2, set_precomments/2.
-spec annotated_type(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract annotated type expression.
The result represents "Name :: Type".
See also: annotated_type_body/1, annotated_type_name/1.
-spec annotated_type_body(syntaxTree()) -> syntaxTree().
Returns the type subtrees of an annotated_type node.
See also: annotated_type/2.
-spec annotated_type_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of an annotated_type node.
See also: annotated_type/2.
-spec application(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract function application expression.
If Arguments is [A1, ..., An], the result represents
"Operator(A1, ..., An)".
See also: application/3, application_arguments/1,
application_operator/1.
-spec application(none | syntaxTree(), syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract function application expression.
If Module is none, this is call is equivalent to
application(Function, Arguments), otherwise it is
equivalent to application(module_qualifier(Module, Function), Arguments).
(This is a utility function.)
See also: application/2, module_qualifier/2.
-spec application_arguments(syntaxTree()) -> [syntaxTree()].
Returns the list of argument subtrees of an application node.
See also: application/2.
-spec application_operator(syntaxTree()) -> syntaxTree().
Returns the operator subtree of an application node.
If Node represents "M:F(...)", then the result is the subtree
representing "M:F".
See also: application/2, module_qualifier/2.
-spec arity_qualifier(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract arity qualifier.
The result represents "Body/Arity".
See also: arity_qualifier_argument/1, arity_qualifier_body/1.
-spec arity_qualifier_argument(syntaxTree()) -> syntaxTree().
Returns the argument (the arity) subtree of an arity_qualifier node.
See also: arity_qualifier/2.
-spec arity_qualifier_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of an arity_qualifier node.
See also: arity_qualifier/2.
-spec atom(atom() | string()) -> syntaxTree().
Creates an abstract atom literal.
The print name of the atom is the character sequence represented by
Name.
See also: atom_literal/1, atom_literal/2, atom_name/1, atom_value/1,
is_atom/2.
-spec atom_literal(syntaxTree()) -> string().
Returns the literal string represented by an atom node.
This includes surrounding single-quote characters if necessary. Characters beyond 255 will be escaped.
Note that, for example, the result of atom("x\ny")
represents any and all of 'x\ny', 'x\12y', 'x\012y', and
'x\^Jy'; see string/1.
-spec atom_literal(syntaxTree(), utf8 | unicode | latin1) -> string().
Returns the literal string represented by an atom node.
This includes surrounding single-quote characters if
necessary. Depending on the encoding a character beyond 255 will be
escaped (latin1) or copied as is (utf8).
See also: atom/1, atom_literal/1, string/1.
-spec atom_name(syntaxTree()) -> string().
Returns the printname of an atom node.
See also: atom/1.
-spec atom_value(syntaxTree()) -> atom().
Returns the value represented by an atom node.
See also: atom/1.
-spec attribute(syntaxTree()) -> syntaxTree().
Equivalent to attribute(Name, none).
-spec attribute(syntaxTree(), none | [syntaxTree()]) -> syntaxTree().
Creates an abstract program attribute.
If Arguments is [A1, ..., An], the result represents
"-Name(A1, ..., An).". Otherwise, if Arguments is none,
the result represents "-Name.". The latter form makes it possible
to represent preprocessor directives such as "-endif.". Attributes
are source code forms.
Note
The preprocessor macro definition directive "
-define(Name, Body)." has relatively few requirements on the syntactical form ofBody(viewed as a sequence of tokens). Thetextnode type can be used for aBodythat is not a normal Erlang construct.
See also: attribute/1, attribute_arguments/1, attribute_name/1,
is_form/1, text/1.
-spec attribute_arguments(syntaxTree()) -> none | [syntaxTree()].
Returns the list of argument subtrees of an attribute node, if any.
If Node represents "-Name.", the result is none. Otherwise, if
Node represents "-Name(E1, ..., En).", [E1, ..., E1] is
returned.
See also: attribute/1.
-spec attribute_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of an attribute node.
See also: attribute/1.
-spec binary([syntaxTree()]) -> syntaxTree().
Creates an abstract binary-object template.
If Fields is [F1, ..., Fn], the result represents "<<F1, ..., Fn>>".
See also: binary_field/2, binary_fields/1.
-spec binary_comp(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract binary comprehension.
If Body is [E1, ..., En], the result represents "<<Template || E1, ..., En>>".
See also: binary_comp_body/1, binary_comp_template/1, generator/2.
-spec binary_comp_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a binary_comp node.
See also: binary_comp/2.
-spec binary_comp_template(syntaxTree()) -> syntaxTree().
Returns the template subtree of a binary_comp node.
See also: binary_comp/2.
-spec binary_field(syntaxTree()) -> syntaxTree().
Equivalent to binary_field(Body, []).
-spec binary_field(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract binary template field.
If Types is the empty list, the result simply represents
"Body", otherwise, if Types is [T1, ..., Tn], the result
represents "Body/T1-...-Tn".
See also: binary/1, binary_field/1, binary_field/3,
binary_field_body/1, binary_field_size/1, binary_field_types/1.
-spec binary_field(syntaxTree(), none | syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract binary template field.
If Size is none, this is equivalent to "binary_field(Body, Types)", otherwise it is equivalent to
"binary_field(size_qualifier(Body, Size), Types)".
(This is a utility function.)
See also: binary/1, binary_field/2, size_qualifier/2.
-spec binary_field_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a binary_field.
See also: binary_field/2.
-spec binary_field_size(syntaxTree()) -> none | syntaxTree().
Returns the size specifier subtree of a binary_field node, if any.
If Node represents "Body:Size" or "Body:Size/T1, ..., Tn", the result is Size, otherwise none is returned.
(This is a utility function.)
See also: binary_field/2, binary_field/3.
-spec binary_field_types(syntaxTree()) -> [syntaxTree()].
Returns the list of type-specifier subtrees of a binary_field node.
If Node represents ".../T1, ..., Tn", the result is [T1, ..., Tn], otherwise the result is the empty list.
See also: binary_field/2.
-spec binary_fields(syntaxTree()) -> [syntaxTree()].
Returns the list of field subtrees of a binary node.
See also: binary/1, binary_field/2.
-spec binary_generator(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract binary_generator.
The result represents "Pattern <= Body".
See also: binary_comp/2, binary_generator_body/1,
binary_generator_pattern/1, list_comp/2, map_comp/2.
-spec binary_generator_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a generator node.
See also: binary_generator/2.
-spec binary_generator_pattern(syntaxTree()) -> syntaxTree().
Returns the pattern subtree of a generator node.
See also: binary_generator/2.
-spec bitstring_type(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract bitstring type.
The result represents "<<_:M, _:_N>>".
See also: bitstring_type_m/1, bitstring_type_n/1.
-spec bitstring_type_m(syntaxTree()) -> syntaxTree().
Returns the number of start bits, M, of a bitstring_type node.
See also: bitstring_type/2.
-spec bitstring_type_n(syntaxTree()) -> syntaxTree().
Returns the segment size, N, of a bitstring_type node.
See also: bitstring_type/2.
-spec block_expr([syntaxTree()]) -> syntaxTree().
Creates an abstract block expression.
If Body is [B1, ..., Bn], the result represents "begin B1, ..., Bn end".
See also: block_expr_body/1.
-spec block_expr_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a block_expr node.
See also: block_expr/1.
-spec case_expr(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract case-expression.
If Clauses is [C1, ..., Cn], the result represents "case Argument of C1; ...; Cn end". More exactly, if each Ci
represents "(Pi) Gi -> Bi", then the result represents "case Argument of P1G1 -> B1; ...; PnGn -> Bn end".
See also: case_expr_argument/1, case_expr_clauses/1, clause/3,
if_expr/1.
-spec case_expr_argument(syntaxTree()) -> syntaxTree().
Returns the argument subtree of a case_expr node.
See also: case_expr/2.
-spec case_expr_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of clause subtrees of a case_expr node.
See also: case_expr/2.
-spec catch_expr(syntaxTree()) -> syntaxTree().
Creates an abstract catch-expression.
The result represents "catch Expr".
See also: catch_expr_body/1.
-spec catch_expr_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a catch_expr node.
See also: catch_expr/1.
-spec char(char()) -> syntaxTree().
Creates an abstract character literal.
The result represents "$Name", where Name corresponds to Value.
Note
The literal corresponding to a particular character value is not
uniquely defined. For example, the character "a" can be written both
as "$a" and "$\141", and a Tab character can be written as
"$\11", "$\011", or "$\t".
See also: char_literal/1, char_literal/2, char_value/1, is_char/2.
-spec char_literal(syntaxTree()) -> nonempty_string().
Returns the literal string represented by a char node.
This includes the leading "$" character. Characters beyond 255 will
be escaped.
See also: char/1.
-spec char_literal(syntaxTree(), encoding()) -> nonempty_string().
Returns the literal string represented by a char node.
This includes the leading "$" character. Depending on the encoding a
character beyond 255 will be escaped (latin1) or copied as is
(utf8).
See also: char/1.
-spec char_value(syntaxTree()) -> char().
Returns the value represented by a char node.
See also: char/1.
-spec class_qualifier(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract class qualifier.
The result represents "Class:Body".
See also: class_qualifier_argument/1, class_qualifier_body/1,
class_qualifier_stacktrace/1, try_expr/4.
-spec class_qualifier(syntaxTree(), syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract class qualifier.
The result represents "Class:Body:Stacktrace".
See also: class_qualifier_argument/1, class_qualifier_body/1,
try_expr/4.
-spec class_qualifier_argument(syntaxTree()) -> syntaxTree().
Returns the argument (the class) subtree of a class_qualifier node.
See also: class_qualifier/2.
-spec class_qualifier_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a class_qualifier node.
See also: class_qualifier/2.
-spec class_qualifier_stacktrace(syntaxTree()) -> syntaxTree().
Returns the stacktrace subtree of a class_qualifier node.
See also: class_qualifier/2.
-spec clause(guard(), [syntaxTree()]) -> syntaxTree().
Equivalent to clause([], Guard, Body).
-spec clause([syntaxTree()], guard(), [syntaxTree()]) -> syntaxTree().
Creates an abstract clause.
If Patterns is [P1, ..., Pn] and Body is [B1, ..., Bm], then
if Guard is none, the result represents "(P1, ..., Pn) -> B1, ..., Bm", otherwise, unless Guard is a list, the result
represents "(P1, ..., Pn) when Guard -> B1, ..., Bm".
For simplicity, the Guard argument may also be any of the following:
- An empty list
[]. This is equivalent to passingnone. - A nonempty list
[E1, ..., Ej]of syntax trees. This is equivalent to passingconjunction([E1, ..., Ej]). - A nonempty list of lists of syntax trees
[[E1_1, ..., E1_k1], ..., [Ej_1, ..., Ej_kj]], which is equivalent to passingdisjunction([conjunction([E1_1, ..., E1_k1]), ..., conjunction([Ej_1, ..., Ej_kj])]).
See also: clause/2, clause_body/1, clause_guard/1, clause_patterns/1.
-spec clause_body(syntaxTree()) -> [syntaxTree()].
Return the list of body subtrees of a clause node.
See also: clause/3.
-spec clause_guard(syntaxTree()) -> none | syntaxTree().
Returns the guard subtree of a clause node, if any.
If Node represents "(P1, ..., Pn) when Guard -> B1, ..., Bm", Guard is returned. Otherwise, the result is none.
See also: clause/3.
-spec clause_patterns(syntaxTree()) -> [syntaxTree()].
Returns the list of pattern subtrees of a clause node.
See also: clause/3.
-spec comment([string()]) -> syntaxTree().
Equivalent to comment(none, Strings).
-spec comment(padding(), [string()]) -> syntaxTree().
Creates an abstract comment with the given padding and text.
If Strings is a (possibly empty) list ["Txt1", ..., "TxtN"],
the result represents the source code text
Txt1
...
TxtNPadding states the number of empty character positions to the left of the
comment separating it horizontally from source code on the same line (if any).
If Padding is none, a default positive number is used. If Padding is an
integer less than 1, there should be no separating space. Comments are in
themselves regarded as source program forms.
-spec comment_padding(syntaxTree()) -> padding().
Returns the amount of padding before the comment, or none.
none means that a default padding may be used.
See also: comment/2.
-spec comment_text(syntaxTree()) -> [string()].
Returns the lines of text of the abstract comment.
See also: comment/2.
-spec compact_list(syntaxTree()) -> syntaxTree().
Yields the most compact form for an abstract list skeleton.
The result either represents "[E1, ..., En | Tail]", where
Tail is not a list skeleton, or otherwise simply "[E1, ..., En]". Annotations on subtrees of Node that represent list
skeletons may be lost, but comments will be propagated to the
result. Returns Node itself if Node does not represent a list
skeleton.
See also: list/2, normalize_list/1.
-spec concrete(syntaxTree()) -> term().
Returns the Erlang term represented by a syntax tree.
Evaluation fails with reason badarg if Node does not represent a
literal term.
Note
The set of syntax trees which have a concrete representation is larger than the set of trees which can be built using the function
abstract/1. An abstract character will be concretised as an integer, whileabstract/1does not at present yield an abstract character for any input. (Use thechar/1function to explicitly create an abstract character.)
Note
arity_qualifiernodes are recognized. This is to follow the Erlang Parser when it comes to wild attributes: both{F, A}andF/Aare recognized, which makes it possible to turn wild attributes into recognized attributes without at the same time making it impossible to compile files using the new syntax with the old version of the Erlang Compiler.
See also: abstract/1, char/1, is_literal/1.
-spec conjunction([syntaxTree()]) -> syntaxTree().
Creates an abstract conjunction.
If List is [E1, ..., En], the result represents "E1, ..., En".
See also: conjunction_body/1, disjunction/1.
-spec conjunction_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a conjunction node.
See also: conjunction/1.
-spec cons(syntaxTree(), syntaxTree()) -> syntaxTree().
"Optimizing" list skeleton cons operation.
Creates an abstract list skeleton whose first element is Head and
whose tail corresponds to Tail. This is similar to list([Head], Tail), except that Tail must not be none,
and the result does not necessarily represent exactly "[Head | Tail]", but
may depend on the Tail subtree.
For example, if Tail represents [X, Y], the result may represent
"[Head, X, Y]", rather than "[Head | [X, Y]]". Annotations on
Tail itself may be lost if Tail represents a list skeleton, but
comments on Tail are propagated to the result.
See also: list/2, list_head/1, list_tail/1.
-spec constrained_function_type(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract constrained function type.
If FunctionConstraint is [C1, ..., Cn], the result represents
"FunctionType when C1, ...Cn".
See also: constrained_function_type_argument/1,
constrained_function_type_body/1.
-spec constrained_function_type_argument(syntaxTree()) -> syntaxTree().
Returns the function constraint subtree of a constrained_function_type node.
See also: constrained_function_type/2.
-spec constrained_function_type_body(syntaxTree()) -> syntaxTree().
Returns the function type subtree of a constrained_function_type node.
See also: constrained_function_type/2.
-spec constraint(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract (subtype) constraint.
The result represents "Name :: Type".
See also: constraint_argument/1, constraint_body/1.
-spec constraint_argument(syntaxTree()) -> syntaxTree().
Returns the name subtree of a constraint node.
See also: constraint/2.
-spec constraint_body(syntaxTree()) -> [syntaxTree()].
Returns the type subtree of a constraint node.
See also: constraint/2.
-spec copy_ann(syntaxTree(), syntaxTree()) -> syntaxTree().
Copies the list of user annotations from Source to Target.
Note: this is equivalent to set_ann(Target, get_ann(Source)),
but potentially more efficient.
-spec copy_attrs(syntaxTree(), syntaxTree()) -> syntaxTree().
Copies the attributes from Source to Target.
Note: this is equivalent to
set_attrs(Target, get_attrs(Source)), but potentially more
efficient.
See also: get_attrs/1, set_attrs/2.
-spec copy_comments(syntaxTree(), syntaxTree()) -> syntaxTree().
Copies the pre- and postcomments from Source to Target.
Note: This is equivalent to
set_postcomments(set_precomments(Target, get_precomments(Source)), get_postcomments(Source)),
but potentially more efficient.
See also: comment/2, get_postcomments/1, get_precomments/1,
set_postcomments/2, set_precomments/2.
-spec copy_pos(syntaxTree(), syntaxTree()) -> syntaxTree().
Copies the annotation from Source to Target.
This is equivalent to set_pos(Target, get_pos(Source)), but
potentially more efficient.
-spec data(syntaxTree()) -> term().
For special purposes only. Returns the associated data of a syntax tree node.
Evaluation fails with reason badarg if is_tree(Node) does not
yield true.
See also: tree/2.
-spec disjunction([syntaxTree()]) -> syntaxTree().
Creates an abstract disjunction.
If List is [E1, ..., En], the result represents "E1; ...; En".
See also: conjunction/1, disjunction_body/1.
-spec disjunction_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a disjunction node.
See also: disjunction/1.
-spec else_expr([syntaxTree()]) -> syntaxTree().
Creates an abstract else-expression.
If Clauses is [C1, ..., Cn], the result
represents "else C1; ...; Cn end". More exactly, if each Ci represents
"(Pi) Gi -> Bi", then the result represents
"else (P1) G1 -> B1; ...; (Pn) Gn -> Bn end".
See also: clause/3, else_expr_clauses/1, maybe_expr/2.
-spec else_expr_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of clause subtrees of an else_expr node.
See also: else_expr/1.
-spec eof_marker() -> syntaxTree().
Creates an abstract end-of-file marker.
This represents the end of input when reading a sequence of source code forms. An end-of-file marker is itself regarded as a source code form (namely, the last in any sequence in which it occurs). It has no defined lexical form.
Note
This is retained only for backwards compatibility with existing parsers and tools.
See also: error_marker/1, is_form/1, warning_marker/1.
-spec error_marker(term()) -> syntaxTree().
Creates an abstract error marker.
The result represents an occurrence of an error in the source code,
with an associated Erlang I/O ErrorInfo structure given by Error
(see module //stdlib/io for details). Error markers are
regarded as source code forms, but have no defined lexical form.
Note
This is supported only for backwards compatibility with existing parsers and tools.
See also: eof_marker/0, error_marker_info/1, is_form/1,
warning_marker/1.
-spec error_marker_info(syntaxTree()) -> term().
Returns the ErrorInfo structure of an error_marker node.
See also: error_marker/1.
-spec flatten_form_list(syntaxTree()) -> syntaxTree().
Flattens sublists of a form_list node.
Returns Node with all subtrees of type form_list recursively
expanded, yielding a single "flat" abstract form sequence.
See also: form_list/1.
-spec float(float()) -> syntaxTree().
Creates an abstract floating-point literal.
The lexical representation is the decimal floating-point numeral of
Value.
See also: float_literal/1, float_value/1.
-spec float_literal(syntaxTree()) -> string().
Returns the numeral string represented by a float node.
See also: float/1.
-spec float_value(syntaxTree()) -> float().
Returns the value represented by a float node.
Note that floating-point values should usually not be compared for equality.
See also: float/1.
-spec form_list([syntaxTree()]) -> syntaxTree().
Creates an abstract sequence of "source code forms".
If Forms is [F1, ..., Fn], where each Fi is a form (see
is_form/1), the result represents:
F1
...
Fnwhere the Fi are separated by one or more line breaks. A node of type
form_list is itself regarded as a source code form; see flatten_form_list/1.
Note
This is simply a way of grouping source code forms into a single syntax tree, usually to form an Erlang module definition.
See also: flatten_form_list/1, form_list_elements/1, is_form/1.
-spec form_list_elements(syntaxTree()) -> [syntaxTree()].
Returns the list of subnodes of a form_list node.
See also: form_list/1.
-spec fun_expr([syntaxTree()]) -> syntaxTree().
Creates an abstract fun-expression.
If Clauses is [C1, ..., Cn], the result represents "fun C1; ...; Cn end". More exactly, if each Ci represents "(Pi1, ..., Pim) Gi -> Bi", then the result represents "fun (P11, ..., P1m) G1 -> B1; ...; (Pn1, ..., Pnm) Gn -> Bn end".
See also: fun_expr_arity/1, fun_expr_clauses/1.
-spec fun_expr_arity(syntaxTree()) -> arity().
Returns the arity of a fun_expr node.
The result is the number of parameter patterns in the first clause of the fun-expression; subsequent clauses are ignored.
An exception is thrown if fun_expr_clauses(Node)
returns an empty list, or if the first element of that list is not a syntax tree
C of type clause such that clause_patterns(C) is a
nonempty list.
See also: clause/3, clause_patterns/1, fun_expr/1, fun_expr_clauses/1.
-spec fun_expr_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of clause subtrees of a fun_expr node.
See also: fun_expr/1.
-spec fun_type() -> syntaxTree().
Creates an abstract fun of any type.
The result represents "fun()".
-spec function(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract function definition.
If Clauses is [C1, ..., Cn], the result represents "Name C1; ...; Name Cn.". More exactly, if each Ci represents "(Pi1, ..., Pim) Gi -> Bi", then the result represents "Name(P11, ..., P1m) G1 -> B1; ...; Name(Pn1, ..., Pnm) Gn -> Bn.".
Function definitions are source code forms.
See also: function_arity/1, function_clauses/1, function_name/1,
is_form/1.
-spec function_arity(syntaxTree()) -> arity().
Returns the arity of a function node.
The result is the number of parameter patterns in the first clause of the function; subsequent clauses are ignored.
An exception is thrown if function_clauses(Node)
returns an empty list, or if the first element of that list is not a syntax tree
C of type clause such that clause_patterns(C) is a
nonempty list.
See also: clause/3, clause_patterns/1, function/2, function_clauses/1.
-spec function_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of clause subtrees of a function node.
See also: function/2.
-spec function_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a function node.
See also: function/2.
-spec function_type(syntaxTree()) -> syntaxTree().
Equivalent to function_type(any_arity, Type).
-spec function_type(any_arity | [syntaxTree()], syntaxTree()) -> syntaxTree().
Creates an abstract function type.
If Arguments is [T1, ..., Tn] and it occurs within a function
specification, the result represents "(T1, ...Tn) -> Return";
otherwise it represents "fun((T1, ...Tn) -> Return)". If
Arguments is any_arity, it represents "fun((...) -> Return)".
Note that the erl_parse representation is identical for
"FunctionType" and "fun(FunctionType)".
See also: function_type_arguments/1, function_type_return/1.
-spec function_type_arguments(syntaxTree()) -> any_arity | [syntaxTree()].
Returns the argument types subtrees of a function_type node.
If Node represents "fun((...) -> Return)", any_arity is
returned; otherwise, if Node represents "(T1, ...Tn) -> Return" or "fun((T1, ...Tn) -> Return)", [T1, ..., Tn] is
returned.
See also: function_type/1, function_type/2.
-spec function_type_return(syntaxTree()) -> syntaxTree().
Returns the return type subtrees of a function_type node.
See also: function_type/1, function_type/2.
-spec generator(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract list generator.
The result represents "Pattern <- Body".
See also: binary_comp/2, generator_body/1, generator_pattern/1,
map_comp/2, list_comp/2.
-spec generator_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a generator node.
See also: generator/2.
-spec generator_pattern(syntaxTree()) -> syntaxTree().
Returns the pattern subtree of a generator node.
See also: generator/2.
-spec get_ann(syntaxTree()) -> [term()].
Returns the list of user annotations associated with a syntax tree.
For a newly created node, this is the empty list. The annotations may be any terms.
See also: get_attrs/1, set_ann/2.
-spec get_attrs(syntaxTree()) -> syntaxTreeAttributes().
Returns a representation of the attributes associated with a syntax tree node.
The attributes are all the extra information that can be attached to a node.
Currently, this includes position information, source code comments, and user
annotations. The result of this function cannot be inspected directly; only
attached to another node (see set_attrs/2).
For accessing individual attributes, see get_pos/1, get_ann/1,
get_precomments/1 and get_postcomments/1.
See also: get_ann/1, get_pos/1, get_postcomments/1, get_precomments/1,
set_attrs/2.
-spec get_pos(syntaxTree()) -> annotation_or_location().
Returns the annotation (see //stdlib/erl_anno) associated with
Node.
By default, all new tree nodes have their associated position
information set to the integer zero. Use
//stdlib/erl_anno:location/1 or
//stdlib/erl_anno:line/1 to get the position information.
See also: get_attrs/1, set_pos/2.
-spec get_postcomments(syntaxTree()) -> [syntaxTree()].
Returns the associated post-comments of a node.
This is a possibly empty list of abstract comments, in top-down textual order. When the code is formatted, post-comments are typically displayed to the right of and/or below the node. For example:
{foo, X, Y} % Post-comment of tupleIf possible, the comment should be moved past any following separator characters on the same line, rather than placing the separators on the following line. For example:
foo([X | Xs], Y) ->
foo(Xs, bar(X)); % Post-comment of 'bar(X)' node
...(where the comment is moved past the rightmost ")" and the ";").
See also: comment/2, get_attrs/1, get_precomments/1,
set_postcomments/2.
-spec get_precomments(syntaxTree()) -> [syntaxTree()].
Returns the associated pre-comments of a node.
This is a possibly empty list of abstract comments, in top-down textual order. When the code is formatted, pre-comments are typically displayed directly above the node. For example:
% Pre-comment of function
foo(X) -> {bar, X}.If possible, the comment should be moved before any preceding separator characters on the same line. For example:
foo([X | Xs]) ->
% Pre-comment of 'bar(X)' node
[bar(X) | foo(Xs)];
...(where the comment is moved before the "[").
See also: comment/2, get_attrs/1, get_postcomments/1,
set_precomments/2.
-spec has_comments(syntaxTree()) -> boolean().
Yields false if the node has no associated comments, and true otherwise.
Note: This is equivalent to
(get_precomments(Node) == []) and (get_postcomments(Node) == []), but
potentially more efficient.
See also: get_postcomments/1, get_precomments/1, remove_comments/1.
-spec if_expr([syntaxTree()]) -> syntaxTree().
Creates an abstract if-expression.
If Clauses is [C1, ..., Cn], the result represents "if C1; ...; Cn end". More exactly, if each Ci represents "() Gi -> Bi",
then the result represents "if G1 -> B1; ...; Gn -> Bn end".
See also: case_expr/2, clause/3, if_expr_clauses/1.
-spec if_expr_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of clause subtrees of an if_expr node.
See also: if_expr/1.
-spec implicit_fun(syntaxTree()) -> syntaxTree().
Creates an abstract "implicit fun" expression.
The result represents "fun Name". Name should represent either
F/A or M:F/A
See also: arity_qualifier/2, implicit_fun/2, implicit_fun/3,
implicit_fun_name/1, module_qualifier/2.
-spec implicit_fun(syntaxTree(), none | syntaxTree()) -> syntaxTree().
Creates an abstract "implicit fun" expression.
If Arity is none, this is equivalent to
implicit_fun(Name), otherwise it is equivalent
to implicit_fun(arity_qualifier(Name, Arity)).
(This is a utility function.)
See also: implicit_fun/1, implicit_fun/3.
-spec implicit_fun(none | syntaxTree(), syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract module-qualified "implicit fun" expression.
If Module is none, this is equivalent to implicit_fun(Name, Arity), otherwise it is equivalent to
implicit_fun(module_qualifier(Module, arity_qualifier(Name, Arity)).
(This is a utility function.)
See also: implicit_fun/1, implicit_fun/2.
-spec implicit_fun_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of an implicit_fun node.
If Node represents "fun N/A" or "fun M:N/A", then the
result is the subtree representing "N/A" or "M:N/A", respectively.
See also: arity_qualifier/2, implicit_fun/1, module_qualifier/2.
-spec infix_expr(syntaxTree(), syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract infix operator expression.
The result represents "Left Operator Right".
See also: infix_expr_left/1, infix_expr_operator/1, infix_expr_right/1,
prefix_expr/2.
-spec infix_expr_left(syntaxTree()) -> syntaxTree().
Returns the left argument subtree of an infix_expr node.
See also: infix_expr/3.
-spec infix_expr_operator(syntaxTree()) -> syntaxTree().
Returns the operator subtree of an infix_expr node.
See also: infix_expr/3.
-spec infix_expr_right(syntaxTree()) -> syntaxTree().
Returns the right argument subtree of an infix_expr node.
See also: infix_expr/3.
-spec integer(integer()) -> syntaxTree().
Creates an abstract integer literal.
The lexical representation is the canonical decimal numeral of Value.
See also: integer_literal/1, integer_value/1, is_integer/2.
-spec integer_literal(syntaxTree()) -> string().
Returns the numeral string represented by an integer node.
See also: integer/1.
-spec integer_range_type(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract range type.
The result represents "Low .. High".
See also: integer_range_type_high/1, integer_range_type_low/1.
-spec integer_range_type_high(syntaxTree()) -> syntaxTree().
Returns the high limit of an integer_range_type node.
See also: integer_range_type/2.
-spec integer_range_type_low(syntaxTree()) -> syntaxTree().
Returns the low limit of an integer_range_type node.
See also: integer_range_type/2.
-spec integer_value(syntaxTree()) -> integer().
Returns the value represented by an integer node.
See also: integer/1.
-spec is_atom(syntaxTree(), atom()) -> boolean().
Returns true if Node has type atom and represents Value, otherwise
false.
See also: atom/1.
-spec is_char(syntaxTree(), char()) -> boolean().
Returns true if Node has type char and represents Value, otherwise
false.
See also: char/1.
-spec is_form(syntaxTree()) -> boolean().
Returns true if Node is a syntax tree representing a so-called "source code
form", otherwise false.
Forms are the Erlang source code units which, placed in sequence, constitute an Erlang program. Current form types are:
attributecommenterror_markereof_markerform_listfunctionwarning_markertext
See also: attribute/2, comment/2, eof_marker/0, error_marker/1,
form_list/1, function/2, type/1, warning_marker/1.
-spec is_integer(syntaxTree(), integer()) -> boolean().
Returns true if Node has type integer and represents Value, otherwise
false.
See also: integer/1.
-spec is_leaf(syntaxTree()) -> boolean().
Returns true if Node is a leaf node, otherwise false.
The currently recognised leaf node types are:
atomcharcommenteof_markererror_markerfloatfun_typeintegerniloperatorstringtextunderscorevariablewarning_marker
A node of type map_expr is a leaf node if and only if it has no argument and
no fields. A node of type map_type is a leaf node if and only if it has no
fields (any_size). A node of type tuple is a leaf node if and only if its
arity is zero. A node of type tuple_type is a leaf node if and only if it has
no elements (any_size).
Note: not all literals are leaf nodes, and vice versa. For example, tuples with nonzero arity and nonempty lists may be literals, but are not leaf nodes. Variables, on the other hand, are leaf nodes but not literals.
See also: is_literal/1, type/1.
-spec is_list_skeleton(syntaxTree()) -> boolean().
Returns true if Node has type list or nil, otherwise false.
-spec is_literal(syntaxTree()) -> boolean().
Returns true if Node represents a literal term, otherwise false.
This function returns true if and only if the value of
concrete(Node) is defined.
See also: abstract/1, concrete/1.
-spec is_proper_list(syntaxTree()) -> boolean().
Returns true if Node represents a proper list, and false otherwise.
A proper list is a list skeleton either on the form "[]" or "[E1, ..., En]", or "[... | Tail]" where recursively Tail also
represents a proper list.
Note
Since
Nodeis a syntax tree, the actual run-time values corresponding to its subtrees can often be partially or completely unknown. For example, ifNoderepresents "[... | Ns]" (whereNsis a variable), the function will returnfalsebecause it is not known whetherNswill be bound to a list at run-time. Conversely, ifNoderepresents, for example, "[1, 2, 3]" or "[A | []]", the function will returntrue.
See also: list/2.
-spec is_string(syntaxTree(), string()) -> boolean().
Returns true if Node has type string and represents Value, otherwise
false.
See also: string/1.
-spec is_tree(syntaxTree()) -> boolean().
For special purposes only. Returns true if Tree is an abstract syntax tree
and false otherwise.
Note
This function yields
falsefor all "old-style"erl_parse-compatible "parse trees".
See also: tree/2.
-spec join_comments(syntaxTree(), syntaxTree()) -> syntaxTree().
Appends the comments of Source to the current comments of Target.
Note: This is equivalent to
add_postcomments(get_postcomments(Source), add_precomments(get_precomments(Source), Target)),
but potentially more efficient.
See also: add_postcomments/2, add_precomments/2, comment/2,
get_postcomments/1, get_precomments/1.
-spec list([syntaxTree()]) -> syntaxTree().
Equivalent to list(List, none).
-spec list([syntaxTree()], none | syntaxTree()) -> syntaxTree().
Constructs an abstract list skeleton.
The result has type list or nil. If List is a nonempty list
[E1, ..., En], the result has type list and represents either
"[E1, ..., En]" if Tail is none, or otherwise "[E1, ..., En | Tail]". If List is the empty list, Tail must be none,
and in that case the result has type nil and represents "[]" (see
nil/0).
The difference between lists as semantic objects (built up of individual "cons" and "nil" terms) and the various syntactic forms for denoting lists may be bewildering at first. This module provides functions both for exact control of the syntactic representation as well as for the simple composition and deconstruction in terms of cons and head/tail operations.
Note
In
list(Elements, none), the "nil" list terminator is implicit and has no associated information (seeget_attrs/1). However, in the seemingly equivalentlist(Elements, Tail)whereTailhas the typenil, the list terminator subtreeTailmay have attached attributes such as position, comments, and annotations, which will be preserved in the result.
See also: compact_list/1, cons/2, get_attrs/1, is_list_skeleton/1,
is_proper_list/1, list/1, list_elements/1, list_head/1, list_length/1,
list_prefix/1, list_suffix/1, list_tail/1, nil/0, normalize_list/1.
-spec list_comp(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract list comprehension.
If Body is [E1, ..., En], the result represents "[Template || E1, ..., En]".
See also: generator/2, list_comp_body/1, list_comp_template/1.
-spec list_comp_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a list_comp node.
See also: list_comp/2.
-spec list_comp_template(syntaxTree()) -> syntaxTree().
Returns the template subtree of a list_comp node.
See also: list_comp/2.
-spec list_elements(syntaxTree()) -> [syntaxTree()].
Returns the list of element subtrees of a list skeleton.
Node must represent a proper list. For example, if Node represents
"[X1, X2 | [X3, X4 | []]", then
list_elements(Node) yields the list [X1, X2, X3, X4].
See also: is_proper_list/1, list/2.
-spec list_head(syntaxTree()) -> syntaxTree().
Returns the head element subtree of a list node.
If Node represents "[Head ...]", the result will represent "Head".
See also: cons/2, list/2, list_tail/1.
-spec list_length(syntaxTree()) -> non_neg_integer().
Returns the number of element subtrees of a list skeleton.
Node must represent a proper list. For example, if Node represents
"[X1 | [X2, X3 | [X4, X5, X6]]]", then
list_length(Node) returns the integer 6.
Note
This is equivalent to
length(list_elements(Node)), but potentially more efficient.
See also: is_proper_list/1, list/2, list_elements/1.
-spec list_prefix(syntaxTree()) -> [syntaxTree()].
Returns the prefix element subtrees of a list node.
If Node represents "[E1, ..., En]" or "[E1, ..., En | Tail]", the returned value is [E1, ..., En].
See also: list/2.
-spec list_suffix(syntaxTree()) -> none | syntaxTree().
Returns the suffix subtree of a list node, if one exists.
If Node represents "[E1, ..., En | Tail]", the returned value is
Tail. Otherwise, if Node represents "[E1, ..., En]", none is
returned.
Note
Even if this function returns a
Tailthat is notnone, the type ofTailcan benilif the tail has been given explicitly and the list skeleton has not been compacted (seecompact_list/1).
See also: compact_list/1, list/2, nil/0.
-spec list_tail(syntaxTree()) -> syntaxTree().
Returns the tail of a list node.
If Node represents a single-element list "[E]", then the result
has type nil, representing "[]". If Node represents "[E1, E2 ...]", the result will represent "[E2 ...]", and if Node
represents "[Head | Tail]", the result will represent
"Tail".
See also: cons/2, list/2, list_head/1.
-spec macro(syntaxTree()) -> syntaxTree().
Equivalent to macro(Name, none).
-spec macro(syntaxTree(), none | [syntaxTree()]) -> syntaxTree().
Creates an abstract macro application.
If Arguments is none, the result represents "?Name",
otherwise, if Arguments is [A1, ..., An], the result represents
"?Name(A1, ..., An)".
Notes: if Arguments is the empty list, the result will thus represent
"?Name()", including a pair of matching parentheses.
The only syntactical limitation imposed by the preprocessor on the arguments to
a macro application (viewed as sequences of tokens) is that they must be
balanced with respect to parentheses, brackets, begin ... end, case ... end,
and so on. The text node type can be used to represent arguments which are not
regular Erlang constructs.
See also: macro/1, macro_arguments/1, macro_name/1, text/1.
-spec macro_arguments(syntaxTree()) -> none | [syntaxTree()].
Returns the list of argument subtrees of a macro node, if any.
If Node represents "?Name", none is returned. Otherwise, if
Node represents "?Name(A1, ..., An)", [A1, ..., An] is
returned.
See also: macro/2.
-spec macro_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a macro node.
See also: macro/2.
-spec make_tree(atom(), [[syntaxTree()]]) -> syntaxTree().
Creates a syntax tree with the given type and subtrees.
Type must be a node type name (see type/1) that does not denote a
leaf node type (see is_leaf/1). Groups must be a nonempty list
of groups of syntax trees, representing the subtrees of a node of the
given type, in left-to-right order as they would occur in the printed
program text, grouped by category as done by subtrees/1.
The result of
copy_attrs(Node, make_tree(type(Node), subtrees(Node))) (see
update_tree/2) represents the same source code text as the original Node,
assuming that subtrees(Node) yields a nonempty list. However,
it does not necessarily have the same data representation as Node.
See also: copy_attrs/2, is_leaf/1, subtrees/1, type/1,
update_tree/2.
-spec map_comp(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract map comprehension.
If Body is [E1, ..., En], the result represents "#{Template || E1, ..., En}".
See also: generator/2, map_comp_body/1, map_comp_template/1.
-spec map_comp_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a map_comp node.
See also: map_comp/2.
-spec map_comp_template(syntaxTree()) -> syntaxTree().
Returns the template subtree of a map_comp node.
See also: map_comp/2.
-spec map_expr([syntaxTree()]) -> syntaxTree().
Equivalent to map_expr(none, Fields).
-spec map_expr(none | syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract map expression.
If Fields is [F1, ..., Fn], then if Argument is none, the
result represents "#{F1, ..., Fn}", otherwise it represents
"Argument#{F1, ..., Fn}".
See also: map_expr/1, map_expr_argument/1, map_expr_fields/1,
map_field_assoc/2, map_field_exact/2.
-spec map_expr_argument(syntaxTree()) -> none | syntaxTree().
Returns the argument subtree of a map_expr node, if any.
If Node represents "#{...}", none is returned. Otherwise, if
Node represents "Argument#{...}", Argument is returned.
See also: map_expr/2.
-spec map_expr_fields(syntaxTree()) -> [syntaxTree()].
Returns the list of field subtrees of a map_expr node.
See also: map_expr/2.
-spec map_field_assoc(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract map assoc field.
The result represents "Name => Value".
See also: map_expr/2, map_field_assoc_name/1, map_field_assoc_value/1.
-spec map_field_assoc_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a map_field_assoc node.
See also: map_field_assoc/2.
-spec map_field_assoc_value(syntaxTree()) -> syntaxTree().
Returns the value subtree of a map_field_assoc node.
See also: map_field_assoc/2.
-spec map_field_exact(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract map exact field.
The result represents "Name := Value".
See also: map_expr/2, map_field_exact_name/1, map_field_exact_value/1.
-spec map_field_exact_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a map_field_exact node.
See also: map_field_exact/2.
-spec map_field_exact_value(syntaxTree()) -> syntaxTree().
Returns the value subtree of a map_field_exact node.
See also: map_field_exact/2.
-spec map_generator(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract map_generator.
The result represents "Pattern <- Body".
See also: binary_comp/2, list_comp/2, map_comp/2, map_generator_body/1,
map_generator_pattern/1.
-spec map_generator_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a map_generator node.
See also: map_generator/2.
-spec map_generator_pattern(syntaxTree()) -> syntaxTree().
Returns the pattern subtree of a map_generator node.
See also: map_generator/2.
-spec map_type() -> syntaxTree().
Equivalent to map_type(any_size).
-spec map_type(any_size | [syntaxTree()]) -> syntaxTree().
Creates an abstract type map.
If Fields is [F1, ..., Fn], the result represents "#{F1, ..., Fn}"; otherwise, if Fields is any_size, it represents
"map/0".
See also: map_type_fields/1.
-spec map_type_assoc(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract map type assoc field.
The result represents "Name => Value".
See also: map_type/1, map_type_assoc_name/1, map_type_assoc_value/1.
-spec map_type_assoc_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a map_type_assoc node.
See also: map_type_assoc/2.
-spec map_type_assoc_value(syntaxTree()) -> syntaxTree().
Returns the value subtree of a map_type_assoc node.
See also: map_type_assoc/2.
-spec map_type_exact(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract map type exact field.
The result represents "Name := Value".
See also: map_type/1, map_type_exact_name/1, map_type_exact_value/1.
-spec map_type_exact_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a map_type_exact node.
See also: map_type_exact/2.
-spec map_type_exact_value(syntaxTree()) -> syntaxTree().
Returns the value subtree of a map_type_exact node.
See also: map_type_exact/2.
-spec map_type_fields(syntaxTree()) -> any_size | [syntaxTree()].
Returns the list of field subtrees of a map_type node.
If Node represents "map/0", any_size is returned; otherwise,
if Node represents "#{F1, ..., Fn}", [F1, ..., Fn] is
returned.
See also: map_type/0, map_type/1.
-spec match_expr(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract match-expression.
The result represents "Pattern = Body".
See also: match_expr_body/1, match_expr_pattern/1.
-spec match_expr_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a match_expr node.
See also: match_expr/2.
-spec match_expr_pattern(syntaxTree()) -> syntaxTree().
Returns the pattern subtree of a match_expr node.
See also: match_expr/2.
-spec maybe_expr([syntaxTree()]) -> syntaxTree().
Equivalent to maybe_expr(Body, none).
-spec maybe_expr([syntaxTree()], none | syntaxTree()) -> syntaxTree().
Creates an abstract maybe-expression.
If Body is [B1, ..., Bn], and OptionalElse is none, the result
represents "maybe B1, ..., Bn end". If Body is [B1, ..., Bn], and OptionalElse reprsents an else_expr node with clauses
[C1, ..., Cn], the result represents "maybe B1, ..., Bn else C1; ..., Cn end".
See clause for documentation on erl_parse clauses.
See also: maybe_expr_body/1, maybe_expr_else/1.
-spec maybe_expr_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a maybe_expr node.
See also: maybe_expr/2.
-spec maybe_expr_else(syntaxTree()) -> none | syntaxTree().
Returns the else subtree of a maybe_expr node.
See also: maybe_expr/2.
-spec maybe_match_expr(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract maybe-expression, as used in maybe blocks.
The result represents "Pattern ?= Body".
See also: maybe_expr/2, maybe_match_expr_body/1,
maybe_match_expr_pattern/1.
-spec maybe_match_expr_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a maybe_expr node.
See also: maybe_match_expr/2.
-spec maybe_match_expr_pattern(syntaxTree()) -> syntaxTree().
Returns the pattern subtree of a maybe_expr node.
See also: maybe_match_expr/2.
-spec meta(syntaxTree()) -> syntaxTree().
Creates a meta-representation of a syntax tree.
The result represents an Erlang expression "MetaTree" which, if
evaluated, will yield a new syntax tree representing the same source
code text as Tree (although the actual data representation may be
different). The expression represented by MetaTree is
implementation independent with regard to the data structures used
by the abstract syntax tree implementation. Comments attached to nodes
of Tree will be preserved, but other attributes are lost.
Any node in Tree whose node type is variable (see type/1), and whose list
of annotations (see get_ann/1) contains the atom meta_var, will remain
unchanged in the resulting tree, except that exactly one occurrence of
meta_var is removed from its annotation list.
The main use of the function meta/1 is to transform a
data structure Tree, which represents a piece of program code, into
a form that is representation independent when printed. For example,
suppose Tree represents a variable named "V". Then (assuming a
function print/1 for printing syntax trees), evaluating
print(abstract(Tree)) — simply using abstract/1 to map the actual
data structure onto a syntax tree representation — would output a
string that might look something like "{tree, variable, ..., "V", ...}", which is obviously dependent on the implementation of the
abstract syntax trees. This could, for example, be useful for caching
a syntax tree in a file. However, in some situations like in a program
generator generator (with two "generator"), it may be
unacceptable. Using print(meta(Tree)) instead would output a
representation independent syntax tree generating expression; in the
above case, something like "erl_syntax:variable("V")".
See also: abstract/1, get_ann/1, type/1.
-spec module_qualifier(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract module qualifier.
The result represents "Module:Body".
See also: module_qualifier_argument/1, module_qualifier_body/1.
-spec module_qualifier_argument(syntaxTree()) -> syntaxTree().
Returns the argument (the module) subtree of a module_qualifier node.
See also: module_qualifier/2.
-spec module_qualifier_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a module_qualifier node.
See also: module_qualifier/2.
-spec named_fun_expr(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract named fun-expression.
If Clauses is [C1, ..., Cn], the result represents "fun Name C1; ...; Name Cn end". More exactly, if each Ci
represents "(Pi1, ..., Pim) Gi -> Bi", then the result
represents "fun Name(P11, ..., P1m) G1 -> B1; ...; Name(Pn1, ..., Pnm) Gn -> Bn end".
See also: named_fun_expr_arity/1, named_fun_expr_clauses/1,
named_fun_expr_name/1.
-spec named_fun_expr_arity(syntaxTree()) -> arity().
Returns the arity of a named_fun_expr node.
The result is the number of parameter patterns in the first clause of the named fun-expression; subsequent clauses are ignored.
An exception is thrown if
named_fun_expr_clauses(Node) returns an empty
list, or if the first element of that list is not a syntax tree C of type
clause such that clause_patterns(C) is a nonempty
list.
See also: clause/3, clause_patterns/1, named_fun_expr/2,
named_fun_expr_clauses/1.
-spec named_fun_expr_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of clause subtrees of a named_fun_expr node.
See also: named_fun_expr/2.
-spec named_fun_expr_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a named_fun_expr node.
See also: named_fun_expr/2.
-spec normalize_list(syntaxTree()) -> syntaxTree().
Expands an abstract list skeleton to its most explicit form.
If Node represents "[E1, ..., En | Tail]", the result
represents "[E1 | ... [En | Tail1] ... ]", where Tail1 is
the result of normalize_list(Tail). If Node
represents "[E1, ..., En]", the result simply represents "[E1 | ... [En | []] ... ]". If Node does not represent a list
skeleton, Node itself is returned.
See also: compact_list/1, list/2.
-spec operator(atom() | string()) -> syntaxTree().
Creates an abstract operator.
The name of the operator is the character sequence represented by
Name. This is analogous to the print name of an atom, but an
operator is never written within single-quotes; for example, the
result of operator('++') represents "++" rather
than "'++'".
See also: atom/1, operator_literal/1, operator_name/1.
-spec operator_literal(syntaxTree()) -> string().
Returns the literal string represented by an operator node.
This is simply the operator name as a string.
See also: operator/1.
-spec operator_name(syntaxTree()) -> atom().
Returns the name of an operator node.
Note that the name is returned as an atom.
See also: operator/1.
-spec parentheses(syntaxTree()) -> syntaxTree().
Creates an abstract parenthesised expression.
The result represents "(Body)", independently of the context.
See also: parentheses_body/1.
-spec parentheses_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a parentheses node.
See also: parentheses/1.
-spec prefix_expr(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract prefix operator expression.
The result represents "Operator Argument".
See also: infix_expr/3, prefix_expr_argument/1, prefix_expr_operator/1.
-spec prefix_expr_argument(syntaxTree()) -> syntaxTree().
Returns the argument subtree of a prefix_expr node.
See also: prefix_expr/2.
-spec prefix_expr_operator(syntaxTree()) -> syntaxTree().
Returns the operator subtree of a prefix_expr node.
See also: prefix_expr/2.
-spec receive_expr([syntaxTree()]) -> syntaxTree().
Equivalent to receive_expr(Clauses, none, []).
-spec receive_expr([syntaxTree()], none | syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract receive-expression.
If Timeout is none, the result represents "receive C1; ...; Cn end" (the Action argument is ignored). Otherwise, if
Clauses is [C1, ..., Cn] and Action is [A1, ..., Am], the
result represents "receive C1; ...; Cn after Timeout -> A1, ..., Am end". More exactly, if each Ci represents "(Pi) Gi -> Bi", then the result represents "receive P1 G1 -> B1; ...; Pn Gn -> Bn ... end".
Note that in Erlang, a receive-expression must have at least one clause if no timeout part is specified.
See also: case_expr/2, clause/3, receive_expr/1,
receive_expr_action/1, receive_expr_clauses/1, receive_expr_timeout/1.
-spec receive_expr_action(syntaxTree()) -> [syntaxTree()].
Returns the list of action body subtrees of a receive_expr node.
If Node represents "receive C1; ...; Cn end", this is the
empty list.
See also: receive_expr/3.
-spec receive_expr_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of clause subtrees of a receive_expr node.
See also: receive_expr/3.
-spec receive_expr_timeout(syntaxTree()) -> none | syntaxTree().
Returns the timeout subtree of a receive_expr node, if any.
If Node represents "receive C1; ...; Cn end", none is
returned. Otherwise, if Node represents "receive C1; ...; Cn after Timeout -> ... end", Timeout is returned.
See also: receive_expr/3.
-spec record_access(syntaxTree(), syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract record field access expression.
The result represents "Argument#Type.Field".
See also: record_access_argument/1, record_access_field/1,
record_access_type/1, record_expr/3.
-spec record_access_argument(syntaxTree()) -> syntaxTree().
Returns the argument subtree of a record_access node.
See also: record_access/3.
-spec record_access_field(syntaxTree()) -> syntaxTree().
Returns the field subtree of a record_access node.
See also: record_access/3.
-spec record_access_type(syntaxTree()) -> syntaxTree().
Returns the type subtree of a record_access node.
See also: record_access/3.
-spec record_expr(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Equivalent to record_expr(none, Type, Fields).
-spec record_expr(none | syntaxTree(), syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract record expression.
If Fields is [F1, ..., Fn], then if Argument is none, the
result represents "#Type{F1, ..., Fn}", otherwise it
represents "Argument#Type{F1, ..., Fn}".
See also: record_access/3, record_expr/2, record_expr_argument/1,
record_expr_fields/1, record_expr_type/1, record_field/2,
record_index_expr/2.
-spec record_expr_argument(syntaxTree()) -> none | syntaxTree().
Returns the argument subtree of a record_expr node, if any.
If Node represents "#Type{...}", none is returned. Otherwise,
if Node represents "Argument#Type{...}", Argument is
returned.
See also: record_expr/3.
-spec record_expr_fields(syntaxTree()) -> [syntaxTree()].
Returns the list of field subtrees of a record_expr node.
See also: record_expr/3.
-spec record_expr_type(syntaxTree()) -> syntaxTree().
Returns the type subtree of a record_expr node.
See also: record_expr/3.
-spec record_field(syntaxTree()) -> syntaxTree().
Equivalent to record_field(Name, none).
-spec record_field(syntaxTree(), none | syntaxTree()) -> syntaxTree().
Creates an abstract record field specification.
If Value is none, the result represents simply "Name",
otherwise it represents "Name = Value".
See also: record_expr/3, record_field_name/1, record_field_value/1.
-spec record_field_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a record_field node.
See also: record_field/2.
-spec record_field_value(syntaxTree()) -> none | syntaxTree().
Returns the value subtree of a record_field node, if any.
If Node represents "Name", none is returned. Otherwise, if
Node represents "Name = Value", Value is returned.
See also: record_field/2.
-spec record_index_expr(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract record field index expression. The result represents
"#Type.Field".
Note
The function name
record_index/2is reserved by the Erlang compiler, which is why that name could not be used for this constructor.
See also: record_expr/3, record_index_expr_field/1,
record_index_expr_type/1.
-spec record_index_expr_field(syntaxTree()) -> syntaxTree().
Returns the field subtree of a record_index_expr node.
See also: record_index_expr/2.
-spec record_index_expr_type(syntaxTree()) -> syntaxTree().
Returns the type subtree of a record_index_expr node.
See also: record_index_expr/2.
-spec record_type(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract record type.
If Fields is [F1, ..., Fn], the result represents "#Name{F1, ..., Fn}".
See also: record_type_fields/1, record_type_name/1.
-spec record_type_field(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract record type field.
The result represents "Name :: Type".
See also: record_type_field_name/1, record_type_field_type/1.
-spec record_type_field_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a record_type_field node.
See also: record_type_field/2.
-spec record_type_field_type(syntaxTree()) -> syntaxTree().
Returns the type subtree of a record_type_field node.
See also: record_type_field/2.
-spec record_type_fields(syntaxTree()) -> [syntaxTree()].
Returns the fields subtree of a record_type node.
See also: record_type/2.
-spec record_type_name(syntaxTree()) -> syntaxTree().
Returns the name subtree of a record_type node.
See also: record_type/2.
-spec remove_comments(syntaxTree()) -> syntaxTree().
Clears the associated comments of Node.
Note: This is equivalent to
set_precomments(set_postcomments(Node, []), []), but
potentially more efficient.
See also: set_postcomments/2, set_precomments/2.
-spec revert(syntaxTree()) -> syntaxTree().
Returns an erl_parse-compatible representation of a syntax tree, if possible.
If Tree represents a well-formed Erlang program or expression, the conversion
should work without problems. Typically, is_tree/1 yields true if conversion
failed (that is, the result is still an abstract syntax tree), and false
otherwise.
The is_tree/1 test is not completely foolproof. For a few special
node types (for example arity_qualifier), if such a node occurs in a
context where it is not expected, it will be left unchanged as a
non-reverted subtree of the result. This can only happen if Tree
does not actually represent legal Erlang code.
See also: //stdlib/erl_parse, revert_forms/1.
Reverts a sequence of Erlang source code forms.
The sequence can be given either as a form_list syntax tree
(possibly nested), or as a list of "program form" syntax trees. If
successful, the corresponding flat list of erl_parse-compatible
syntax trees is returned (see revert/1). If some program form could
not be reverted, {error, Form} is thrown. Standalone comments in the
form sequence are discarded.
See also: form_list/1, is_form/1, revert/1.
-spec set_ann(syntaxTree(), [term()]) -> syntaxTree().
Sets the list of user annotations of Node to Annotations.
See also: add_ann/2, copy_ann/2, get_ann/1.
-spec set_attrs(syntaxTree(), syntaxTreeAttributes()) -> syntaxTree().
Sets the attributes of Node to Attributes.
See also: copy_attrs/2, get_attrs/1.
-spec set_pos(syntaxTree(), annotation_or_location()) -> syntaxTree().
Sets the position information of Node to Pos.
See also: copy_pos/2, get_pos/1.
-spec set_postcomments(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Sets the post-comments of Node to Comments.
Comments should be a possibly empty list of abstract comments, in
top-down textual order
See also: add_postcomments/2, comment/2, copy_comments/2,
get_postcomments/1, join_comments/2, remove_comments/1,
set_precomments/2.
-spec set_precomments(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Sets the pre-comments of Node to Comments.
Comments should be a possibly empty list of abstract comments, in
top-down textual order.
See also: add_precomments/2, comment/2, copy_comments/2,
get_precomments/1, join_comments/2, remove_comments/1,
set_postcomments/2.
-spec size_qualifier(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract size qualifier.
The result represents "Body:Size".
See also: size_qualifier_argument/1, size_qualifier_body/1.
-spec size_qualifier_argument(syntaxTree()) -> syntaxTree().
Returns the argument subtree (the size) of a size_qualifier node.
See also: size_qualifier/2.
-spec size_qualifier_body(syntaxTree()) -> syntaxTree().
Returns the body subtree of a size_qualifier node.
See also: size_qualifier/2.
-spec string(string()) -> syntaxTree().
Creates an abstract string literal.
The result represents "Text" (including the surrounding
double-quotes), where Text corresponds to the sequence of characters
in Value, but not representing a specific string literal.
For example, the result of string("x\ny") represents any and all
of "x\ny", "x\12y", "x\012y" and "x\^Jy"; see char/1.
See also: char/1, is_string/2, string_literal/1, string_literal/2,
string_value/1.
-spec string_literal(syntaxTree()) -> nonempty_string().
Returns the literal string represented by a string node.
This includes surrounding double-quote characters. Characters beyond 255 will be escaped.
See also: string/1.
-spec string_literal(syntaxTree(), encoding()) -> nonempty_string().
Returns the literal string represented by a string node.
This includes surrounding double-quote characters. Depending on the
encoding characters beyond 255 will be escaped (latin1) or copied as
is (utf8).
See also: string/1.
-spec string_value(syntaxTree()) -> string().
Returns the value represented by a string node.
See also: string/1.
-spec subtrees(syntaxTree()) -> [[syntaxTree()]].
Returns the grouped list of all subtrees of a syntax tree.
If Node is a leaf node (see is_leaf/1), this is the empty list,
otherwise the result is always a nonempty list, containing the lists
of subtrees of Node, in left-to-right order as they occur in the
printed program text, and grouped by category. Often, each group
contains only a single subtree.
Depending on the type of Node, the size of some groups may be
variable (for example, the group consisting of all the elements of a
tuple), while others always contain the same number of elements —
usually exactly one (for example, the group containing the argument
expression of a case-expression). Note, however, that the exact
structure of the returned list (for a given node type) should in
general not be depended upon, since it might be subject to change
without notice.
The function subtrees/1 and the constructor functions make_tree/2 and
update_tree/2 can be a great help if one wants to traverse a syntax tree,
visiting all its subtrees, but treat nodes of the tree in a uniform way in most
or all cases. Using these functions makes this simple, and also assures that
your code is not overly sensitive to extensions of the syntax tree data type,
because any node types not explicitly handled by your code can be left to a
default case.
For example:
postorder(F, Tree) ->
F(case subtrees(Tree) of
[] -> Tree;
List -> update_tree(Tree,
[[postorder(F, Subtree)
|| Subtree <- Group]
|| Group <- List])
end).maps the function F on Tree and all its subtrees, doing a post-order
traversal of the syntax tree. (Note the use of update_tree/2 to preserve node
attributes.) For a simple function like:
f(Node) ->
case type(Node) of
atom -> atom("a_" ++ atom_name(Node));
_ -> Node
end.the call postorder(fun f/1, Tree) will yield a new representation of Tree in
which all atom names have been extended with the prefix "a_", but nothing else
(including comments, annotations, and line numbers) has been changed.
See also: copy_attrs/2, is_leaf/1, make_tree/2, type/1.
-spec text(string()) -> syntaxTree().
Creates an abstract piece of source code text.
The result represents exactly the sequence of characters in
String. This is useful in cases where one wants full control of the
resulting output, such as the appearance of floating-point numbers or
macro definitions.
See also: text_string/1.
-spec text_string(syntaxTree()) -> string().
Returns the character sequence represented by a text node.
See also: text/1.
Equivalent to tree(Type, []).
For special purposes only. Creates an abstract syntax tree node with type tag
Type and associated data Data.
This function and the related is_tree/1 and data/1 provide a uniform way to
extend the set of erl_parse node types. The associated data is any term, whose
format may depend on the type tag.
Notes
Any nodes created outside of this module must have type tags distinct from those currently defined by this module; see
type/1for a complete list.The type tag of a syntax tree node may also be used as a primary tag by the
erl_parserepresentation; in that case, the selector functions for that node type must handle both the abstract syntax tree and theerl_parseform. The functiontype(T)should return the correct type tag regardless of the representation ofT, so that the user sees no difference betweenerl_syntaxanderl_parsenodes.
-spec try_after_expr([syntaxTree()], [syntaxTree()]) -> syntaxTree().
Equivalent to try_expr(Body, [], [], After).
-spec try_expr([syntaxTree()], [syntaxTree()]) -> syntaxTree().
Equivalent to try_expr(Body, [], Handlers).
-spec try_expr([syntaxTree()], [syntaxTree()], [syntaxTree()]) -> syntaxTree().
Equivalent to try_expr(Body, Clauses, Handlers, []).
-spec try_expr([syntaxTree()], [syntaxTree()], [syntaxTree()], [syntaxTree()]) -> syntaxTree().
Creates an abstract try-expression.
If Body is [B1, ..., Bn], Clauses is [C1, ..., Cj], Handlers
is [H1, ..., Hk], and After is [A1, ..., Am], the result
represents "try B1, ..., Bn of C1; ...; Cj catch H1; ...; Hk after A1, ..., Am end". More exactly, if each Ci represents "(CPi) CGi -> CBi", and each Hi represents "(HPi) HGi -> HBi", then the
result represents "try B1, ..., Bn of CP1 CG1 -> CB1; ...; CPj CGj -> CBj catch HP1 HG1 -> HB1; ...; HPk HGk -> HBk after A1, ..., Am end";
see case_expr/2. If Clauses is the empty list, the of ...
section is left out. If After is the empty list, the after ...
section is left out. If Handlers is the empty list, and After is
nonempty, the catch ... section is left out.
See also: case_expr/2, class_qualifier/2, clause/3, try_after_expr/2,
try_expr/2, try_expr/3, try_expr_after/1, try_expr_body/1,
try_expr_clauses/1, try_expr_handlers/1.
-spec try_expr_after(syntaxTree()) -> [syntaxTree()].
Returns the list of "after" subtrees of a try_expr node.
See also: try_expr/4.
-spec try_expr_body(syntaxTree()) -> [syntaxTree()].
Returns the list of body subtrees of a try_expr node.
See also: try_expr/4.
-spec try_expr_clauses(syntaxTree()) -> [syntaxTree()].
Returns the list of case-clause subtrees of a try_expr node. If Node
represents "try Body catch H1; ...; Hn end", the result is the empty
list.
See also: try_expr/4.
-spec try_expr_handlers(syntaxTree()) -> [syntaxTree()].
Returns the list of handler-clause subtrees of a try_expr node.
See also: try_expr/4.
-spec tuple([syntaxTree()]) -> syntaxTree().
Creates an abstract tuple.
If Elements is [X1, ..., Xn], the result represents "{X1, ..., Xn}".
Note
The Erlang language has distinct 1-tuples, meaning
{X}is always distinct fromXitself.
See also: tuple_elements/1, tuple_size/1.
-spec tuple_elements(syntaxTree()) -> [syntaxTree()].
Returns the list of element subtrees of a tuple node.
See also: tuple/1.
-spec tuple_size(syntaxTree()) -> non_neg_integer().
Returns the number of elements of a tuple node.
Note
This is equivalent to
length(tuple_elements(Node)), but potentially more efficient.
See also: tuple/1, tuple_elements/1.
-spec tuple_type() -> syntaxTree().
Equivalent to tuple_type(any_size).
-spec tuple_type(any_size | [syntaxTree()]) -> syntaxTree().
Creates an abstract type tuple.
If Elements is [T1, ..., Tn], the result represents "{T1, ..., Tn}"; otherwise, if Elements is any_size, it represents
"tuple/0".
See also: tuple_type_elements/1.
-spec tuple_type_elements(syntaxTree()) -> any_size | [syntaxTree()].
Returns the list of type element subtrees of a tuple_type node.
If Node represents "tuple/0", any_size is returned; otherwise,
if Node represents "{T1, ..., Tn}", [T1, ..., Tn] is returned.
See also: tuple_type/0, tuple_type/1.
-spec type(syntaxTree()) -> atom().
Returns the type tag of Node.
If Node does not represent a syntax tree, evaluation fails with
reason badarg. Node types currently defined by this module are:
applicationannotated_typearity_qualifieratomattributebinarybinary_fieldbitstring_typeblock_exprcase_exprcatch_exprcharclass_qualifierclausecommentconjunctionconstrained_function_typeconstraintdisjunctionelse_expreof_markererror_markerfloatform_listfun_exprfun_typefunctionfunction_typegeneratorif_exprimplicit_funinfix_exprintegerinteger_range_typelistlist_compmacromap_exprmap_field_assocmap_field_exactmap_typemap_type_assocmap_type_exactmatch_exprmaybe_exprmaybe_match_exprmodule_qualifiernamed_fun_exprniloperatorparenthesesprefix_exprreceive_exprrecord_accessrecord_exprrecord_fieldrecord_index_exprrecord_typerecord_type_fieldsize_qualifierstringtexttry_exprtupletuple_typetyped_record_fieldtype_applicationtype_unionunderscoreuser_type_applicationvariablewarning_marker
The user may (for special purposes) create additional nodes with other type
tags, using the tree/2 function.
Note: The primary constructor functions for a node type should always have the same name as the node type itself.
See also: annotated_type/2, application/3, arity_qualifier/2, atom/1,
attribute/2, binary/1, binary_field/2, bitstring_type/2, block_expr/1,
case_expr/2, catch_expr/1, char/1, class_qualifier/2, clause/3,
comment/2, conjunction/1, constrained_function_type/2, constraint/2,
disjunction/1, else_expr/1, eof_marker/0, error_marker/1, float/1,
form_list/1, fun_expr/1, fun_type/0, function/2, function_type/1,
function_type/2, generator/2, if_expr/1, implicit_fun/2, infix_expr/3,
integer/1, integer_range_type/2, list/2, list_comp/2, macro/2,
map_expr/2, map_field_assoc/2, map_field_exact/2, map_type/0,
map_type/1, map_type_assoc/2, map_type_exact/2, match_expr/2,
maybe_expr/1, maybe_expr/2, maybe_match_expr/2, module_qualifier/2,
named_fun_expr/2, nil/0, operator/1, parentheses/1, prefix_expr/2,
receive_expr/3, record_access/3, record_expr/2, record_field/2,
record_index_expr/2, record_type/2, record_type_field/2,
size_qualifier/2, string/1, text/1, tree/2, try_expr/3, tuple/1,
tuple_type/0, tuple_type/1, type_application/2, type_union/1,
typed_record_field/2, underscore/0, user_type_application/2, variable/1,
warning_marker/1.
-spec type_application(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract type application expression.
If Arguments is [T1, ..., Tn], the result represents
"TypeName(T1, ...Tn)".
See also: type_application/3, type_application_arguments/1,
type_application_name/1, user_type_application/2.
-spec type_application(none | syntaxTree(), syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract type application expression.
If Module is none, this is call is equivalent to
type_application(TypeName, Arguments),
otherwise it is equivalent to
type_application(module_qualifier(Module, TypeName), Arguments).
(This is a utility function.)
See also: module_qualifier/2, type_application/2.
-spec type_application_arguments(syntaxTree()) -> [syntaxTree()].
Returns the arguments subtrees of a type_application node.
See also: type_application/2.
-spec type_application_name(syntaxTree()) -> syntaxTree().
Returns the type name subtree of a type_application node.
See also: type_application/2.
-spec type_union([syntaxTree()]) -> syntaxTree().
Creates an abstract type union.
If Types is [T1, ..., Tn], the result represents "T1 | ... | Tn".
See also: type_union_types/1.
-spec type_union_types(syntaxTree()) -> [syntaxTree()].
Returns the list of type subtrees of a type_union node.
See also: type_union/1.
-spec typed_record_field(syntaxTree(), syntaxTree()) -> syntaxTree().
Creates an abstract typed record field specification.
The result represents "Field :: Type".
See also: typed_record_field_body/1, typed_record_field_type/1.
-spec typed_record_field_body(syntaxTree()) -> syntaxTree().
Returns the field subtree of a typed_record_field node.
See also: typed_record_field/2.
-spec typed_record_field_type(syntaxTree()) -> syntaxTree().
Returns the type subtree of a typed_record_field node.
See also: typed_record_field/2.
-spec underscore() -> syntaxTree().
Creates an abstract universal pattern ("_").
The lexical representation is a single underscore character. Note that this is not a variable, lexically speaking.
See also: variable/1.
-spec update_tree(syntaxTree(), [[syntaxTree()]]) -> syntaxTree().
Creates a syntax tree with the same type and attributes as the given tree.
This is equivalent to copy_attrs(Node, make_tree(type(Node), Groups)).
See also: copy_attrs/2, make_tree/2, type/1.
-spec user_type_application(syntaxTree(), [syntaxTree()]) -> syntaxTree().
Creates an abstract user type.
If Arguments is [T1, ..., Tn], the result represents
"TypeName(T1, ...Tn)".
See also: type_application/2, user_type_application_arguments/1,
user_type_application_name/1.
-spec user_type_application_arguments(syntaxTree()) -> [syntaxTree()].
Returns the arguments subtrees of a user_type_application node.
See also: user_type_application/2.
-spec user_type_application_name(syntaxTree()) -> syntaxTree().
Returns the type name subtree of a user_type_application node.
See also: user_type_application/2.
-spec variable(atom() | string()) -> syntaxTree().
Creates an abstract variable with the given name.
Name may be any atom or string that represents a lexically valid
variable name, but not a single underscore character; see
underscore/0.
Note
No check is performed to verify whether the character sequence represents a proper variable name, that is, whether its first character is an uppercase Erlang character, or whether it contains illegal characters such as control characters or whitespace.
See also: underscore/0, variable_literal/1, variable_name/1.
-spec variable_literal(syntaxTree()) -> string().
Returns the name of a variable node as a string.
See also: variable/1.
-spec variable_name(syntaxTree()) -> atom().
Returns the name of a variable node as an atom.
See also: variable/1.
-spec warning_marker(term()) -> syntaxTree().
Creates an abstract warning marker.
The result represents an occurrence of a possible problem in the
source code, with an associated Erlang I/O ErrorInfo structure given
by Error (see module //stdlib/io for details). Warning
markers are regarded as source code forms, but have no defined lexical
form.
Note
This is supported only for backwards compatibility with existing parsers and tools.
See also: eof_marker/0, error_marker/1, is_form/1,
warning_marker_info/1.
-spec warning_marker_info(syntaxTree()) -> term().
Returns the ErrorInfo structure of a warning_marker node.
See also: warning_marker/1.