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 that are not recommended.

       The errors detected include:

         * Redefined and undefined functions

         * Unbound and unsafe variables

         * Illegal record use

       The warnings detected include:

         * Unused functions and imports

         * Unused variables

         * Variables imported into matches

         * Variables exported from if/case/receive

         * Variables shadowed in funs and list comprehensions

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

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

DATA TYPES

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

       error_description() = term()

EXPORTS

       format_error(ErrorDescriptor) -> io_lib:chars()

              Types:

                 ErrorDescriptor = error_description()

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

       is_guard_test(Expr) -> boolean()

              Types:

                 Expr = erl_parse:abstract_expr()

              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.

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

              Checks all the forms in a module for errors. It returns:

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

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

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

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

              [{FileName2,[ErrorInfo]}]

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

ERROR INFORMATION

       ErrorInfo  is  the standard ErrorInfo structure that is returned from all I/O modules. The
       format is as follows:

       {ErrorLine, Module, ErrorDescriptor}

       A string describing the error is obtained with the following call:

       Module:format_error(ErrorDescriptor)

SEE ALSO

       epp(3erl), erl_parse(3erl)