<commit_before># Copyright (C) 2008, The Perl Foundation.
# $Id$

=head1 NAME

docs/pdds/draft/pdd29_compiler_tools.pod - Parrot Compiler Tools

=head1 VERSION

$Revision$

=head1 MAINTAINER

<NAME>" Coleda
<NAME>

=head1 ABSTRACT

This PDD specifies the Parrot Compiler Tools (PCT).

=head1 SYNOPSIS


=head1 DESCRIPTION


=head1 IMPLEMENTATION


=head1 ATTACHMENTS


=head1 REFERENCES

docs/pdd26_ast.pod


=cut

__END__
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End:<commit_msg>[pdd29] give pdd29 a first swing<commit_after># Copyright (C) 2008, The Perl Foundation.
# $Id$

=head1 NAME

docs/pdds/draft/pdd29_compiler_tools.pod - Parrot Compiler Tools

=head1 VERSION

$Revision$

=head1 MAINTAINER

<NAME>" Coleda
<NAME>

=head1 ABSTRACT

This PDD specifies the Parrot Compiler Tools (PCT).

=head1 SYNOPSIS

Creating a PCT-based compiler can be done as follows:

 .sub 'onload' :anon :load :init
     load_bytecode 'PCT.pbc'
     $P0 = get_hll_global ['PCT'], 'HLLCompiler'
     $P1 = $P0.'new'()
     $P1.'language'('Foo')
     $P1.'parsegrammar'('Foo::Grammar')
     $P1.'parseactions'('Foo::Grammar::Actions')
 .end

 .sub 'main' :main
     .param pmc args
     $P0 = compreg 'Foo'
     $P1 = $P0.'command_line'(args)
 .end

{{ this is the most important part; is this enough? }}

The Parrot distribution contains a Perl script to generate a compiler
stub, containing all necessary files. This generated compiler will
compile out of the box. It is highly suggested to use this script to
get started with the PCT.
The script is located in C<tools/dev/mk_language_shell.pl>.

{{ Not sure whether the mk_language_shell.pl script should be mentioned long term }}


Running the compiler is then done as follows:

 $ parrot foo.pbc [--target=[parse|past|post|pir]] <file>

{{ other options? }}

=head1 DESCRIPTION

The Parrot Compiler Tools are specially designed to easily create a
compiler targeting the Parrot Virtual Machine. The tools themselves
run on Parrot, which implies that no other external programs are
needed.

The PCT is a set of libraries and programs, to:

=over 4

=item * create a parser

=item * create an intermediate data structure (Abstract Syntax Tree)

=item * generate executable code (Parrot Intermediate Representation)

=back



=head1 IMPLEMENTATION

The PCT is made up of the following libraries and programs:

=over 4

=item * Parrot Grammar Engine (PGE)

=item * Parrot Abstract Syntax Tree (PAST) classes

=item * Parrot Opcode Syntax Tree (POST) classes

=item * PCT::HLLCompiler class

=item * PCT::Grammar class

=back

Although strictly speaking it is not part of the PCT, the
Not Quite Perl (6) (NQP) language is typically used in all PCT-based
compilers. NQP is a subset of the Perl 6 language, and is a
high-level language as an alternative for PIR.

=head2 Compilation phases

A PCT-based compiler has by default four compilation phases, or
I<transformations>. Phases can be removed and added through the API of
the C<HLLCompiler> class. These are:

=over 4

=item * source to parse tree

The source is read, parsed and stored in a parse tree.

=item * parse tree to PAST

The parse tree is converted into a Parrot Abstract Syntax Tree.

=item * PAST to POST

The PAST is converted into a Parrot Opcode Syntax Tree.

=item * POST to PIR

The POST is converted into executable Parrot Intermediate Representation.

=back

=head3 Source to Parse Tree

{{ XXX }}

=head3 Parse tree to PAST

{{ XXX }}

=head3 PAST to POST

{{ XXX }}

=head3 POST to PIR

{{ XXX }}

=head2 Parrot Grammar Engine

The Parrot Grammar Engine (PGE) is a component that I<executes> regular
expressions. Besides I<classic> regular expressions, it also understands
Perl 6 Rules. Such rules are special regular expressions to define a grammar.

=head2 PCT::Grammar

The class C<PCT::Grammar> is a built-in grammar class that can be used as
a parent class for a custom grammar. This class defines a number of rules and
tokens that are inherited by child classes. Note that the concept of C<class>
and C<grammar> are equivalent.

The following rules are predefined:

{{ is this necessary, or just a reference to the file? }}

=over 4

=item ident

=item ws

=back

=head2 PCT::HLLCompiler

All PCT-based compilers use a HLLCompiler object as a compiler driver.
This object invokes the different compiler phases.

=head3 HLLCompiler API Methods

{{ TODO: complete this }}

=over 4

=item commandline_prompt

$P0.'commandline_prompt'($S0)

sets the string in C<$S0> as a commandline prompt on the compiler in C<$P0>.
The prompt is the text that is shown on the commandline before a command is
entered when the compiler is started in interactive mode.

=item commandline_banner

$P0.'commandline_banner'($S0)

sets the string in C<$S0> as a commandline banner on the compiler in C<$P0>.
The banner is the first text that is shown when the compiler is started in
interactive mode. This can be used for a copyright notice or other information.

=back


=head1 ATTACHMENTS

None.

=head1 REFERENCES

docs/pdd26_ast.pod

http://dev.perl.org/perl6/doc/design/syn/S05.html

=cut

__END__
Local Variables:
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