erl_lint
The Erlang Code Linter
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.
Functions
module(AbsForms) -> {ok,Warnings} | {error,Errors,Warnings}
module(AbsForms, FileName) -> {ok,Warnings} | {error,Errors,Warnings}
module(AbsForms, FileName, CompileOptions) -> {ok,Warnings} | {error,Errors,Warnings}
AbsForms = [term()]
FileName = FileName2 = atom() | string()
Warnings = Errors = [{Filename2,[ErrorInfo]}]
ErrorInfo = see separate description below.
CompileOptions = [term()]
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(3).
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(3), or parser erl_parse(3) 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) -> bool()
Expr = term()
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) -> Chars
ErrorDescriptor = errordesc()
Chars = [char() | Chars]
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)