package SQL::Translator;
#-----------------------------------------------------
-# $Id: Translator.pm,v 1.3 2002-03-07 14:11:40 dlc Exp $
-#
-# File : SQL/Translator.pm
-# Programmer : Ken Y. Clark, kclark@logsoft.com
-# Created : 2002/02/27
-# Purpose : convert schema from one database to another
+# $Id: Translator.pm,v 1.3.2.1 2002-03-07 14:14:48 dlc Exp $
#-----------------------------------------------------
+# Copyright (C) 2002 Ken Y. Clark <kycl4rk@users.sourceforge.net>,
+# darren chamberlain <darren@cpan.org>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; version 2.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+# 02111-1307 USA
+# -------------------------------------------------------------------
+
+=head1 NAME
+
+SQL::Translator - convert schema from one database to another
+
+=head1 SYNOPSIS
+
+ use SQL::Translator;
+ my $translator = SQL::Translator->new;
+ my $output = $translator->translate(
+ parser => 'mysql',
+ producer => 'oracle',
+ file => $file,
+ ) or die $translator->error;
+ print $output;
+
+=head1 DESCRIPTION
+
+This module attempts to simplify the task of converting one database
+create syntax to another through the use of Parsers and Producers.
+The idea is that any Parser can be used with any Producer in the
+conversion process. So, if you wanted PostgreSQL-to-Oracle, you could
+just write the PostgreSQL parser and use an existing Oracle producer.
+
+Currently, the existing parsers use Parse::RecDescent, and the
+producers are just printing formatted output of the parsed data
+structure. New parsers don't necessarily have to use
+Parse::RecDescent, however, as long as the data structure conforms to
+what the producers are expecting. With this separation of code, it is
+hoped that developers will find it easy to add more database dialects
+by using what's written, writing only what they need, and then
+contributing their parsers or producers back to the project.
+
+=cut
use strict;
-use vars qw( $VERSION );
-$VERSION = (qw$Revision: 1.3 $)[-1];
+use vars qw($VERSION $DEFAULT_SUB $DEBUG);
+$VERSION = sprintf "%d.%02d", q$Revision: 1.3.2.1 $ =~ /(\d+)\.(\d+)/;
+$DEBUG = 1 unless defined $DEBUG;
-use Data::Dumper;
+$DEFAULT_SUB = sub { $_[0] } unless defined $DEFAULT_SUB;
+*isa = \&UNIVERSAL::isa;
-use SQL::Translator::Parser::MySQL;
-use SQL::Translator::Parser::Sybase;
-use SQL::Translator::Producer::Oracle;
-use SQL::Translator::Producer::XML;
+=head1 CONSTRUCTOR
-#
-# These are the inputs we can parse.
-#
-my %parsers = (
- mysql => 'MySQL',
- sybase => 'Sybase',
-);
+The constructor is called B<new>, and accepts a hash of options.
+Valid options are:
-#
-# These are the formats we can produce.
-#
-my %producers = (
- oracle => 'Oracle',
- xml => 'XML',
-);
+=over 4
+
+=item parser (aka from)
+
+=item producer (aka to)
+
+=item filename
+
+=back
+
+All options are, well, optional; these attributes can be set via
+instance methods.
+
+=cut
+
+# {{{ new
-#-----------------------------------------------------
sub new {
-#
-# Makes a new object. Intentionally made very bare as
-# it is used by all subclasses (unless they override,
-# of course).
-#
my $class = shift;
- my %args = @_;
- my $self = { %args };
- return bless $self, $class;
-}
+ my $args = isa($_[0], 'HASH') ? shift : { @_ };
+ my $self = bless { } => $class;
-#-----------------------------------------------------
-sub error {
-#
-# Return the last error.
-#
- return shift()->{'error'} || '';
+ #
+ # Set the parser and producer. If a 'parser' or 'from' parameter
+ # is passed in, use that as the parser; if a 'producer' or 'to'
+ # parameter is passed in, use that as the producer; both default
+ # to $DEFAULT_SUB.
+ #
+ $self->parser( $args->{'parser'} || $args->{'from'} || $DEFAULT_SUB);
+ $self->producer($args->{'producer'} || $args->{'to'} || $DEFAULT_SUB);
+
+ #
+ # Clear the error
+ #
+ $self->error_out("");
+
+ return $self;
}
+# }}}
-#-----------------------------------------------------
-sub error_out {
-#
-# Record the error and return undef.
-#
+=head1 METHODS
+
+
+=head2 B<producer>
+
+The B<producer> method is an accessor/mutator, used to retrieve or
+define what subroutine is called to produce the output. A subroutine
+defined as a producer subroutine will be invoked as a function (not a
+method) and passed a data structure as its only argument. It is
+expected that the function transform the data structure to the output
+format, and return a string.
+
+When defining a producer, one of three things can be passed
+in: A full module name (e.g., My::Groovy::Parser), a module name
+relative to the SQL::Translator::Producer namespace (e.g., MySQL), or
+a reference to an anonymous subroutine. If a full module name is
+passed in, it is treated as a package, and a function called
+"transform" will be invoked as $modulename::transform.
+
+ my $tr = SQL::Translator->new;
+
+ # This will invoke My::Groovy::Producer::transform($data)
+ $tr->producer("My::Groovy::Producer");
+
+ # This will invoke SQL::Translator::Producer::Sybase::transform($data)
+ $tr->producer("Sybase");
+
+ # This will inoke the referenced subroutine directly
+ $tr->producer(\&my_producer);
+
+=cut
+# TODO Make mod_perl-like assumptions about the name being passed in:
+# try to load the module; if that fails, pop off the last piece
+# (everything after the last ::) and try to load that; if that loads,
+# use the popped off piece as the function name, and not transform.
+
+# {{{ producer
+sub producer {
my $self = shift;
- if ( my $error = shift ) {
- $self->{'error'} = $error;
+ if (@_) {
+ my $producer = shift;
+ if ($producer =~ /::/) {
+ load($producer) or die "Can't load $producer: $@";
+ $self->{'producer'} = \&{ "$producer\::'producer'" };
+ $self->debug("Got 'producer': $producer\::'producer'");
+ } elsif (isa($producer, 'CODE')) {
+ $self->{'producer'} = $producer;
+ $self->debug("Got 'producer': code ref");
+ } else {
+ my $Pp = sprintf "SQL::Translator::Producer::$producer";
+ load($Pp) or die "Can't load $Pp: $@";
+ $self->{'producer'} = \&{ "$Pp\::translate" };
+ $self->debug("Got producer: $Pp");
+ }
+ # At this point, $self->{'producer'} contains a subroutine
+ # reference that is ready to run!
}
- return;
+ return $self->{'producer'};
+};
+# }}}
+
+=head2 B<parser>
+
+The B<parser> method defines or retrieves a subroutine that will be
+called to perform the parsing. The basic idea is the same as that of
+B<producer> (see above), except the default subroutine name is
+"parse", and will be invoked as $module_name::parse. Also, the parser
+subroutine will be passed a string containing the entirety of the data
+to be parsed.
+
+ # Invokes SQL::Translator::Parser::MySQL::parse()
+ $tr->parser("MySQL");
+
+ # Invokes My::Groovy::Parser::parse()
+ $tr->parser("My::Groovy::Parser");
+
+ # Invoke an anonymous subroutine directly
+ $tr->parser(sub {
+ my $dumper = Data::Dumper->new([ $_[0] ], [ "SQL" ]);
+ $dumper->Purity(1)->Terse(1)->Deepcopy(1);
+ return $dumper->Dump;
+ });
+
+=cut
+
+# {{{ parser
+sub parser {
+ my $self = shift;
+ if (@_) {
+ my $parser = shift;
+ if ($parser =~ /::/) {
+ load($parser) or die "Can't load $parser: $@";
+ $self->{'parser'} = \&{ "$parser\::parse" };
+ $self->debug("Got parser: $parser\::parse");
+ } elsif (isa($parser, 'CODE')) {
+ $self->{'parser'} = $parser;
+ $self->debug("Got parser: code ref");
+ } else {
+ my $Pp = "SQL::Translator::Parser::$parser";
+ load($Pp) or die "Can't load $Pp: $@";
+ $self->{'parser'} = \&{ "$Pp\::parse" };
+ $self->debug("Got parser: $Pp");
+ }
+ # At this point, $self->{$pp} contains a subroutine
+ # reference that is ready to run!
+ }
+ return $self->{'parser'};
}
+# }}}
-#-----------------------------------------------------
+=head2 B<translate>
+
+The B<translate> method calls the subroutines referenced by the
+B<parser> and B<producer> data members (described above). It accepts
+as arguments a number of things, in key => value format, including
+(potentially) a parser and a producer (they are passed directly to the
+B<parser> and B<producer> methods).
+
+Here is how the parameter list to B<translate> is parsed:
+
+=over
+
+=item *
+
+1 argument means it's the data to be parsed; which could be a string
+(filename), a reference to a GLOB (filehandle from which to read a
+string), a refernce to a scalar (a string stored in memory), or a
+reference to a hash (which means the same thing as below).
+
+ # Parse the file /path/to/datafile
+ my $output = $tr->translate("/path/to/datafile");
+
+ # The same thing:
+ my $fh = IO::File->new("/path/to/datafile");
+ my $output = $tr->translate($fh);
+
+ # Again, the same thing:
+ my $fh = IO::File->new("/path/to/datafile");
+ my $data = { local $/; <$fh> };
+ my $output = $tr->translate(\$data);
+
+=item *
+
+> 1 argument means its a hash of things, and it might be setting a
+parser, producer, or datasource (this key is named "filename" or
+"file" if it's a file, or "data" for a GLOB or SCALAR reference).
+
+ # As above, parse /path/to/datafile, but with different producers
+ for my $prod ("MySQL", "XML", "Sybase") {
+ print $tr->translate(
+ producer => $prod,
+ filename => "/path/to/datafile",
+ );
+ }
+
+ # The filename hash key could also be:
+ datasource => $fh,
+
+ # or
+ datasource => \$data,
+
+You get the idea.
+
+=back
+
+=cut
+
+# {{{ translate
sub translate {
-#
-# Translates any number of given files.
-#
- my ( $self, %args ) = @_;
- my $from = $args{'from'} || '';
- my $to = $args{'to'} || '';
- my $input = $args{'input'} || [];
- my $verbose = $args{'verbose'} || 0;
- my $no_comments = $args{'no_comments'} || 0;
-
- if ( exists $parsers{ $from } ) {
- $self->{'from'} = $from;
- warn "Using parser '$from.'\n" if $verbose;
+ my $self = shift;
+ my ($args, $parser, $producer);
+
+ if (@_ == 1) {
+ if (isa($_[0], 'HASH')) {
+ # Passed a hashref
+ $args = $_[0];
+ }
+ elsif (isa($_[0], 'GLOB')) {
+ # passed a filehandle; slurp it
+ local $/;
+ $args = { data => <$_[0]> };
+ }
+ elsif (isa($_[0], 'SCALAR')) {
+ # passed a ref to a string; deref it
+ $args = { data => ${$_[0]} };
+ }
+ else {
+ # Not a ref, it's a filename
+ $args = { filename => $_[0] };
+ }
}
else {
- my $msg = "The parsers '$from' is not valid.\n" .
- "Please choose from the following list:\n";
- $msg .= " $_\n" for sort keys %parsers;
- return $self->error_out( $msg );
+ # Should we check if @_ % 2, or just eat the errors if they occur?
+ $args = { @_ };
}
- if ( exists $producers{ $to } ) {
- $self->{'to'} = $to;
- warn "Using producer '$to.'\n" if $verbose;
+ if ((defined $args->{'filename'} ||
+ defined $args->{'file'} ) && not $args->{'data'}) {
+ local *FH;
+ local $/;
+
+ open FH, $args->{'filename'} or die $!;
+ $args->{'data'} = <FH>;
+ close FH or die $!;
}
- else {
- my $msg = "The producer '$to' is not valid.\n" .
- "Please choose from the following list:\n";
- $msg .= " $_\n" for sort keys %producers;
- return $self->error_out( $msg );
+
+ #
+ # Last chance to bail out; if there's nothing in the data
+ # key of %args, back out.
+ #
+ return unless defined $args->{'data'};
+
+ #
+ # Local reference to the parser subroutine
+ #
+ if ($parser = ($args->{'parser'} || $args->{'from'})) {
+ $self->parser($parser);
+ } else {
+ $parser = $self->parser;
}
#
- # Slurp the entire text file we're parsing.
+ # Local reference to the producer subroutine
#
- my $parser = $self->parser;
- my $producer = $self->producer;
- my $data;
- for my $file ( @$input ) {
- warn "Parsing file '$file.'\n" if $verbose;
- open my $fh, $file or return $self->error_out( "Can't read $file: $!" );
- local $/;
- $data = $parser->parse( <$fh> );
+ if ($producer = ($args->{'producer'} || $args->{'to'})) {
+ $self->producer($producer);
+ } else {
+ $producer = $self->producer;
}
- warn "Data =\n", Dumper( $data ) if $verbose;
- my $output = $producer->translate( $data );
+ #
+ # Execute the parser, then execute the producer with that output
+ #
+ my $translated = $parser->($args->{'data'});
+
+ return $producer->($translated);
}
+# }}}
+
+=head2 B<error>
+The error method returns the last error.
+
+=cut
+
+# {{{ error
#-----------------------------------------------------
-sub parser {
+sub error {
#
-# Figures out which module to load based on the "from" argument
+# Return the last error.
#
+ return shift()->{'error'} || '';
+}
+# }}}
+
+=head2 B<error_out>
+
+Record the error and return undef. The error can be retrieved by
+calling programs using $tr->error.
+
+For Parser or Producer writers, primarily.
+
+=cut
+
+# {{{ error_out
+sub error_out {
my $self = shift;
- unless ( $self->{'parser'} ) {
- my $parser_module =
- 'SQL::Translator::Parser::'.$parsers{ $self->{'from'} };
- $self->{'parser'} = $parser_module->new;
+ if ( my $error = shift ) {
+ $self->{'error'} = $error;
}
- return $self->{'parser'};
+ return;
}
+# }}}
-#-----------------------------------------------------
-sub producer {
-#
-# Figures out which module to load based on the "to" argument
-#
+=head2 B<debug>
+
+If the global variable $SQL::Translator::DEBUG is set to a true value,
+then calls to $tr->debug($msg) will be carped to STDERR. If $DEBUG is
+not set, then this method does nothing.
+
+=cut
+
+# {{{ debug
+use Carp qw(carp);
+sub debug {
my $self = shift;
- unless ( $self->{'producer'} ) {
- my $from = $parsers{ $self->{'from'} };
- my $producer_module =
- 'SQL::Translator::Producer::'.$producers{ $self->{'to'} };
- $self->{'producer'} = $producer_module->new( from => $from );
- }
- return $self->{'producer'};
+ carp @_ if ($DEBUG);
}
+# }}}
+
+# {{{ load
+sub load {
+ my $module = do { my $m = shift; $m =~ s[::][/]g; "$m.pm" };
+ return 1 if $INC{$module};
+
+ eval { require $module };
+
+ return if ($@);
+ return 1;
+}
+# }}}
1;
+__END__
#-----------------------------------------------------
# Rescue the drowning and tie your shoestrings.
# Henry David Thoreau
#-----------------------------------------------------
-=head1 NAME
-
-SQL::Translator - convert schema from one database to another
-
-=head1 SYNOPSIS
+=head1 AUTHOR
- use SQL::Translator;
- my $translator = SQL::Translator->new;
- my $output = $translator->translate(
- from => 'mysql',
- to => 'oracle',
- file => $file,
- ) or die $translator->error;
- print $output;
+Ken Y. Clark, E<lt>kclark@logsoft.comE<gt>,
+darren chamberlain E<lt>darren@cpan.orgE<gt>
-=head1 DESCRIPTION
+=head1 COPYRIGHT
-This module attempts to simplify the task of converting one database
-create syntax to another through the use of Parsers and Producers.
-The idea is that any Parser can be used with any Producer in the
-conversion process. So, if you wanted PostgreSQL-to-Oracle, you could
-just write the PostgreSQL parser and use an existing Oracle producer.
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; version 2.
-Currently, the existing parsers use Parse::RecDescent, and the
-producers are just printing formatted output of the parsed data
-structure. New parsers don't necessarily have to use
-Parse::RecDescent, however, as long as the data structure conforms to
-what the producers are expecting. With this separation of code, it is
-hoped that developers will find it easy to add more database dialects
-by using what's written, writing only what they need, and then
-contributing their parsers or producers back to the project.
-
-=head1 AUTHOR
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
-Ken Y. Clark, kclark@logsoft.com
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+USA
=head1 SEE ALSO
-perl(1).
+L<perl>, L<Parse::RecDescent>
=cut
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