-spec category(Token) -> category() when Token :: token().

Returns the category of Token.

-spec column(Token) -> erl_anno:column() | undefined when Token :: token().

Returns the column of Token's collection of annotations.

-spec end_location(Token) -> erl_anno:location() | undefined when Token :: token().

Returns the end location of the text of Token's collection of annotations. If there is no text, undefined is returned.

-spec format_error(ErrorDescriptor) -> string() when ErrorDescriptor :: error_description().

Uses an ErrorDescriptor and returns a string that describes the error or warning. This function is usually called implicitly when an ErrorInfo structure is processed (see section Error Information).

-spec line(Token) -> erl_anno:line() when Token :: token().

Returns the line of Token's collection of annotations.

-spec location(Token) -> erl_anno:location() when Token :: token().

Returns the location of Token's collection of annotations.

-spec reserved_word(Atom :: atom()) -> boolean().

Returns true if Atom is an Erlang reserved word, otherwise false.

-spec string(String) -> Return
          when
              String :: string(),
              Return ::
                  {ok, Tokens :: tokens(), EndLocation} |
                  {error, ErrorInfo :: error_info(), ErrorLocation},
              EndLocation :: erl_anno:location(),
              ErrorLocation :: erl_anno:location().

Equivalent to string(String, 1)

-spec string(String, StartLocation) -> Return
          when
              String :: string(),
              Return ::
                  {ok, Tokens :: tokens(), EndLocation} |
                  {error, ErrorInfo :: error_info(), ErrorLocation},
              StartLocation :: erl_anno:location(),
              EndLocation :: erl_anno:location(),
              ErrorLocation :: erl_anno:location().

Equivalent to string(String, StartLocation, [])

-spec string(String, StartLocation, Options) -> Return
          when
              String :: string(),
              Options :: options(),
              Return ::
                  {ok, Tokens :: tokens(), EndLocation} |
                  {error, ErrorInfo :: error_info(), ErrorLocation},
              StartLocation :: erl_anno:location(),
              EndLocation :: erl_anno:location(),
              ErrorLocation :: erl_anno:location().

Takes the list of characters String and tries to scan (tokenize) them.

Returns one of the following:

• {ok, Tokens, EndLocation} - Tokens are the Erlang tokens from String. EndLocation is the first location after the last token.

• {error, ErrorInfo, ErrorLocation} - An error occurred. ErrorLocation is the first location after the erroneous token.

StartLocation indicates the initial location when scanning starts. If StartLocation is a line, Anno, EndLocation, and ErrorLocation are lines. If StartLocation is a pair of a line and a column, Anno takes the form of an opaque compound data type, and EndLocation and ErrorLocation are pairs of a line and a column. The token annotations contain information about the column and the line where the token begins, as well as the text of the token (if option text is specified), all of which can be accessed by calling column/1, line/1, location/1, and text/1.

A token is a tuple containing information about syntactic category, the token annotations, and the terminal symbol. For punctuation characters (such as ; and |) and reserved words, the category and the symbol coincide, and the token is represented by a two-tuple. Three-tuples have one of the following forms:

• {atom, Anno, atom()}
• {char, Anno, char()}
• {comment, Anno, string()}
• {float, Anno, float()}
• {integer, Anno, integer()}
• {var, Anno, atom()}
• {white_space, Anno, string()}

Valid options:

• {reserved_word_fun, reserved_word_fun()} - A callback function that is called when the scanner has found an unquoted atom. If the function returns true, the unquoted atom itself becomes the category of the token. If the function returns false, atom becomes the category of the unquoted atom.

• return_comments - Return comment tokens.

• return_white_spaces - Return white space tokens. By convention, a newline character, if present, is always the first character of the text (there cannot be more than one newline in a white space token).

• return - Short for [return_comments, return_white_spaces].

• text - Include the token text in the token annotation. The text is the part of the input corresponding to the token. See also text_fun.

• {text_fun, text_fun()} - A callback function used to determine whether the full text for the token shall be included in the token annotation. Arguments of the function are the category of the token and the full token string. This is only used when text is not present. If neither are present the text will not be saved in the token annotation.

• {compiler_internal, term()} - Pass compiler-internal options to the scanner. The set of internal options understood by the scanner should be considered experimental and can thus be changed at any time without prior warning.

  The following options are currently understood:

  • ssa_checks - Tokenizes source code annotations used for encoding tests on the BEAM SSA code produced by the compiler.

-spec symbol(Token) -> symbol() when Token :: token().

Returns the symbol of Token.

-spec text(Token) -> erl_anno:text() | undefined when Token :: token().

Returns the text of Token's collection of annotations. If there is no text, undefined is returned.

-spec tokens(Continuation, CharSpec, StartLocation) -> Return
          when
              Continuation :: return_cont() | [],
              CharSpec :: char_spec(),
              StartLocation :: erl_anno:location(),
              Return ::
                  {done, Result :: tokens_result(), LeftOverChars :: char_spec()} |
                  {more, Continuation1 :: return_cont()}.

Equivalent to tokens(Continuation, CharSpec, StartLocation, [])

-spec tokens(Continuation, CharSpec, StartLocation, Options) -> Return
          when
              Continuation :: return_cont() | [],
              CharSpec :: char_spec(),
              StartLocation :: erl_anno:location(),
              Options :: options(),
              Return ::
                  {done, Result :: tokens_result(), LeftOverChars :: char_spec()} |
                  {more, Continuation1 :: return_cont()}.

This is the re-entrant scanner, which scans characters until either a dot ('.' followed by a white space) or eof is reached.

It returns:

• {done, Result, LeftOverChars} - Indicates that there is sufficient input data to get a result. Result is:

  • {ok, Tokens, EndLocation} - The scanning was successful. Tokens is the list of tokens including dot.

  • {eof, EndLocation} - End of file was encountered before any more tokens.

  • {error, ErrorInfo, EndLocation} - An error occurred. LeftOverChars is the remaining characters of the input data, starting from EndLocation.

• {more, Continuation1} - More data is required for building a term. Continuation1 must be passed in a new call to tokens/3,4 when more data is available.

The CharSpec eof signals end of file. LeftOverChars then takes the value eof as well.

For a description of the options, see string/3.