erl_parse

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erl_parse The Erlang Parser

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(3)).

Parse tree for Erlang clause.

Parse tree for Erlang expression.

Parse tree for Erlang form.

Parse an Erlang form

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 Erlang expressions

This function parses Tokens as if it were a list of expressions. It returns:

{ok, ExprList}

The parsing was successful. ExprList is a list of the abstract forms of the parsed expressions.

{error, ErrorInfo}

An error occurred.

Parse an Erlang term

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 Format an error descriptor ErrorDescriptor = error_description() 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).

Generate a list of tokens for an expression

This function generates a list of tokens representing the abstract form AbsTerm of an expression. Optionally, it appends MoreTokens.

Convert abstract form to an Erlang 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.

Convert an Erlang term into an abstract form

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)