trusty (3) erl_lint.3erl.gz

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)