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This module is the basic Erlang parser which converts tokens into the abstract form of either forms (i.e., top-level constructs), expressions, or terms. The Abstract Format is described in the ERTS User's Guide. Note that a token list must end with the dot token in order to be acceptable to the parse functions (see erl_scan).
parse_form(Tokens) -> {ok, AbsForm} | {error, ErrorInfo}
Types:
Tokens = [Token]
Token = {Tag,Line} | {Tag,Line,term()}
Tag = atom()
AbsForm = term()
ErrorInfo = see section Error Information below.
This function parses Tokens as if it were a form. It returns:
{ok, AbsForm}
AbsForm is the
abstract form of the parsed form.
{error, ErrorInfo}
parse_exprs(Tokens) -> {ok, Expr_list} | {error, ErrorInfo}
Types:
Tokens = [Token]
Token = {Tag,Line} | {Tag,Line,term()}
Tag = atom()
Expr_list = [AbsExpr]
AbsExpr = term()
ErrorInfo = see section Error Information below.
This function parses Tokens as if it were a list of expressions. It returns:
{ok, Expr_list}
Expr_list is a
list of the abstract forms of the parsed expressions.
{error, ErrorInfo}
parse_term(Tokens) -> {ok, Term} | {error, ErrorInfo}
Types:
Tokens = [Token]
Token = {Tag,Line} | {Tag,Line,term()}
Tag = atom()
Term = term()
ErrorInfo = see section Error Information below.
This function parses Tokens as if it were a term. It returns:
{ok, Term}
Term is
the Erlang term corresponding to the token list.
{error, ErrorInfo}
format_error(ErrorDescriptor) -> Chars
Types:
ErrorDescriptor = errordesc()
Chars = [char() | Chars]
Uses an ErrorDescriptor and returns a string
which describes the error. This function is usually called
implicitly when an ErrorInfo structure is processed
(see below).
tokens(AbsTerm) -> Tokens
tokens(AbsTerm, MoreTokens) -> Tokens
Types:
Tokens = MoreTokens = [Token]
Token = {Tag,Line} | {Tag,Line,term()}
Tag = atom()
AbsTerm = term()
ErrorInfo = see section Error Information below.
This function generates a list of tokens representing the abstract
form AbsTerm of an expression. Optionally, it appends
Moretokens.
Types:
AbsTerm = Data = term()
Converts the abstract form AbsTerm of a term into a
conventional Erlang data structure (i.e., the term itself).
This is the inverse of abstract/1.
Types:
Data = AbsTerm = term()
Converts the Erlang data structure Data into an
abstract form of type AbsTerm. This is the inverse of
normalise/1.
The ErrorInfo mentioned above is the standard
ErrorInfo structure which is returned from all IO
modules. It has the format:
{ErrorLine, Module, ErrorDescriptor}
A string which describes the error is obtained with the following call:
apply(Module, format_error, ErrorDescriptor)
io(3), erl_scan(3), ERTS User's Guide