bionic (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 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)