NAME

       erl_lint - The Erlang Code Linter

DESCRIPTION

       This  module is used to check Erlang code for illegal syntax and other bugs. It also warns
       against coding practices which are not recommended.

       The errors detected include:

         * redefined and undefined functions

         * unbound and unsafe variables

         * illegal record usage.

       Warnings include:

         * unused functions and imports

         * unused variables

         * variables imported into matches

         * variables exported from if/case/receive

         * variables shadowed in lambdas and list comprehensions.

       Some of the warnings are optional, and can be turned on by giving the appropriate  option,
       described below.

       The functions in this module are invoked automatically by the Erlang compiler and there is
       no reason to invoke these functions separately unless you have  written  your  own  Erlang
       compiler.

DATA TYPES

       error_info() = {erl_scan:line(), module(), error_description()}

       error_description() = term()

EXPORTS

       module(AbsForms) -> {ok, Warnings} | {error, Errors, Warnings}

       module(AbsForms, FileName) ->
                 {ok, Warnings} | {error, Errors, Warnings}

       module(AbsForms, FileName, CompileOptions) ->
                 {ok, Warnings} | {error, Errors, Warnings}

              Types:

                 AbsForms = [erl_parse:abstract_form()]
                 FileName = atom() | string()
                 CompileOptions = [compile:option()]
                 Warnings = [{file:filename(), [ErrorInfo]}]
                 Errors = [{FileName2 :: file:filename(), [ErrorInfo]}]
                 ErrorInfo = error_info()

              This function checks all the forms in a module for errors. It returns:

                {ok,Warnings}:
                  There were no errors in the module.

                {error,Errors,Warnings}:
                  There were errors in the module.

              Since  this  module  is of interest only to the maintainers of the compiler, and to
              avoid having the same description in two places  to  avoid  the  usual  maintenance
              nightmare,  the elements of Options that control the warnings are only described in
              compile(3erl).

              The AbsForms of a module which comes from a file that  is  read  through  epp,  the
              Erlang  pre-processor,  can come from many files. This means that any references to
              errors must include the file name (see epp(3erl), or parser  erl_parse(3erl)).  The
              warnings and errors returned have the following format:

                  [{FileName2,[ErrorInfo]}]

              The  errors  and  warnings are listed in the order in which they are encountered in
              the forms. This means that the errors from one file may  be  split  into  different
              entries in the list of errors.

       is_guard_test(Expr) -> boolean()

              Types:

                 Expr = erl_parse:abstract_expr()

              This  function  tests  if  Expr  is  a  legal  guard  test.  Expr is an Erlang term
              representing the abstract form for  the  expression.  erl_parse:parse_exprs(Tokens)
              can be used to generate a list of Expr.

       format_error(ErrorDescriptor) -> io_lib:chars()

              Types:

                 ErrorDescriptor = error_description()

              Takes an ErrorDescriptor and returns a string which describes the error or warning.
              This function is usually called implicitly when processing an  ErrorInfo  structure
              (see below).

ERROR INFORMATION

       The  ErrorInfo  mentioned above is the standard ErrorInfo structure which is returned from
       all IO modules. It has the following format:

           {ErrorLine, Module, ErrorDescriptor}

       A string which describes the error is obtained with the following call:

           Module:format_error(ErrorDescriptor)

SEE ALSO

       erl_parse(3erl), epp(3erl)