erl_parse(3erl) 					     Erlang Module Definition						   erl_parse(3erl)

NAME

       erl_parse - The Erlang Parser

DESCRIPTION

       This  module  is the basic Erlang parser which converts tokens into the abstract form of either forms (i.e., top-level constructs), expres-
       sions, 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(3erl) ).

EXPORTS

       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} :
		  The parsing was successful. AbsForm is the abstract form of the parsed form.

		{error, ErrorInfo} :
		  An error occurred.

       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} :
		  The parsing was successful. Expr_list is a list of the abstract forms of the parsed expressions.

		{error, ErrorInfo} :
		  An error occurred.

       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} :
		  The parsing was successful. Term is the Erlang term corresponding to the token list.

		{error, ErrorInfo} :
		  An error occurred.

       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
	      .

       normalise(AbsTerm) -> Data

	      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 .

       abstract(Data) -> AbsTerm

	      Types  Data = AbsTerm = term()

	      Converts the Erlang data structure Data into an abstract form of type AbsTerm . This is the inverse of normalise/1 .

ERROR INFORMATION

       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:

	   Module:format_error(ErrorDescriptor)

SEE ALSO

       io(3erl) , erl_scan(3erl) , ERTS User's Guide

Ericsson AB							   stdlib 1.17.3						   erl_parse(3erl)