NAME
MarpaX::Languages::C::AST - Translate a C source to an AST
VERSION
version 0.36
SYNOPSIS
use strict;
use warnings FATAL => 'all';
use MarpaX::Languages::C::AST;
use Log::Log4perl qw/:easy/;
use Log::Any::Adapter;
use Log::Any qw/$log/;
use Data::Dumper;
#
# Init log
#
our $defaultLog4perlConf = '
log4perl.rootLogger = WARN, Screen
log4perl.appender.Screen = Log::Log4perl::Appender::Screen
log4perl.appender.Screen.stderr = 0
log4perl.appender.Screen.layout = PatternLayout
log4perl.appender.Screen.layout.ConversionPattern = %d %-5p %6P %m{chomp}%n
';
Log::Log4perl::init(\$defaultLog4perlConf);
Log::Any::Adapter->set('Log4perl');
#
# Parse C
#
my $cSourceCode = '
typedef struct s1_ {int i1;} x1, y1;
struct x1 {x1 i2;};
x1 x;
';
my $cAstObject = MarpaX::Languages::C::AST->new();
$log->infof('%s', $cAstObject->parse(\$cSourceCode));
DESCRIPTION
This module translates C source into an AST tree. To assist further
process of the AST tree, the nodes of the AST are blessed according to
the C grammar you have selected. (The default is 'ISO-ANSI-C-2011'.) If
you want to enable logging, be aware that this module is a Log::Any
thingy.
This module implements the full syntax, as well as those specification
constraints which are syntactic in nature: Associativity of nested
if-then-else statements is according to the C standards, as is the
treatment of names as typedefs, enums, or variable identifiers.
The C standards contain many constraints that are non-syntactic.
MarpaX::Languages::C::AST does not implement these, leaving them for AST
post-process. One example of a non-syntactic constraint is the
requirement that labeled statements within a function be unique. Another
is the requirement that declarations include at most one storage class
specifier.
SUBROUTINES/METHODS
new($class, %options)
Instantiate a new object. Takes as parameter an optional hash of options
that can be:
grammarName
Name of a grammar. Default is 'ISO-ANSI-C-2011'.
typedef
An array reference to a list of known typedefs, injected at top
scope before parsing start. This option should *not* be used unless
you pass a C source that is incomplete. Typically something that has
not gone through a preprocessor. Default is [] i.e. empty list.
enum
An array reference to a list of known enums, injected at top scope
before parsing start. Alike for typedef, this option should *not* be
used unless you pass a C source that is incomplete. Typically
something that has not gone through a preprocessor. Default is []
i.e. empty list.
lazy
A flag saying the parser to inject automatically all allowed
alternatives when the grammar reaches a
TYPEDEF_NAME/ENUMERATION_CONSTANT/IDENTIFIER ambiguity. This option
should be used in practice only when you are parsing a source code
not pre-processed. Please note that *if* lazy mode is on, there
might be several parse tree values. In such a case, unless the
option $optionalArrayOfValuesb of the value() method is true, the
first of the parse tree values will be returned. If more than one
alternative is accepted, the lexemeCallback (see below) will be, in
order of preference, either TYPEDEF_NAME, ENUMERATION_CONSTANT or
IDENTIFIER. The lazy mode can produce more than one parse tree
value. The options typedef and enum (see upper) can be used to help
lazy mode choose between TYPEDEF_NAME and ENUMERATION_CONSTANT,
while IDENTIFIER will always be pushed as an alternative. Default is
a false value.
start
A string giving the starting point of the grammar. This should be
used when you know that the source code to parse is not a full valid
source, but a portion of if. This requires knowledge of the grammar
rules. Default is empty string: '', i.e. let the grammar apply its
default start rule.
Please note that giving another value but 'translationUnit' will
emit warnings from the grammar, saying that some rules are not
reachable.
logInfo
Reference to an array of lexemes for which a log of level INFO will
be issued.
lexemeCallback
Array reference containing a CODE ref and optional arguments. This
callback will be trigerred like this: &$CODE(@arguments,
$lexemeHashp), where $lexemeHashp is a reference to a hash
describing current lexeme:
name
Name of the lexeme. You have to refer to the grammar used to get
its definition, although this is usually self-explanatory.
start
G1 (Marpa term) start location.
length
Length of the lexeme
line
Line number in the source being parsed.
column
Column number in the source being parsed.
value
String containing lexeme value.
parse($self, $sourcep)
Do the parsing. Takes as parameter the reference to a C source code.
Returns $self, so that chaining with value method will be natural, i.e.
parse()->value().
scope($self)
Returns the MarpaX::Languages::C::AST::Scope object.
value($self, $optionalArrayOfValuesb)
Return the blessed value. Takes as optional parameter a flag saying if
the return value should be an array of all values or not. If this flag
is false, the module will croak if there more than one parse tree value.
If this flag is true, a reference to an array of values will be
returned, even if there is a single parse tree value.
INCOMPATIBILITIES
Since version 0.30, the c2ast.pl script is named c2ast (i.e. without
extension).
NOTES
C code can have inline ASM code. The GCC Inline Assembly is fully
supported, any other is falling into a heuristic that should catch
everything needed. CL inline assemblies have been targetted in
particular.
SEE ALSO
Log::Any, Marpa::R2
SUPPORT
Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker at
T>. You will be notified automatically of any progress on your issue.
Source Code
This is open source software. The code repository is available for
public review and contribution under the terms of the license.
AUTHOR
Jean-Damien Durand <jeandamiendurand@free.fr>
CONTRIBUTORS
* Jeffrey Kegler <JKEGL@cpan.org>
* Jeffrey Kegler <jkegl@cpan.org>
* jddurand <jeandamiendurand@free.fr>
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by Jean-Damien Durand.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.