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:
Warnings include:
if
/case
/receive
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.
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 = [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}
{error,Errors,Warnings}
The elements of Options
selecting optional warnings
are as follows:
{warn_format, Verbosity}
io:format
and similar
functions. Verbosity
selects the amount of
warnings: 0 = no warnings; 1 = warnings for invalid
format strings and incorrect number of arguments; 2 =
warnings also when the validity could not be checked
(for example, when the format string argument is a
variable). The default verbosity is 1. Verbosity 0 can
also be selected by the option nowarn_format
.
warn_unused_vars
nowarn_unused_vars
.
warn_export_vars
nowarn_export_vars
.
warn_shadow_vars
nowarn_shadow_vars
.
warn_unused_import
nowarn_unused_import
.
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.
Types:
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) -> string()
Types:
ErrorDescriptor = errordesc()
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).
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:
apply(Module, format_error, ErrorDescriptor)