# autoconf -- create `configure' using m4 macros# Copyright (C) 2001, 2002 Free Software Foundation, Inc.# 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; either version 2, or (at your option)# any later version.# 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.# This file is basically Perl 5.6's Class::Struct, but made compatible# with Perl 5.5.  If someday this has to be updated, be sure to rename# all the occurrences of Class::Struct into Autom4te::Struct, otherwise# if we `use' a Perl module (e.g., File::stat) that uses Class::Struct,# we would have two packages defining the same symbols.  Boom.package Autom4te::Struct;## See POD after __END__use 5.005_03;use strict;use vars qw(@ISA @EXPORT $VERSION);use Carp;require Exporter;@ISA = qw(Exporter);@EXPORT = qw(struct);$VERSION = '0.58';## Tested on 5.002 and 5.003 without class membership tests:my $CHECK_CLASS_MEMBERSHIP = ($] >= 5.003_95);my $print = 0;sub printem {    if (@_) { $print = shift }    else    { $print++ }}{    package Autom4te::Struct::Tie_ISA;    sub TIEARRAY {        my $class = shift;        return bless [], $class;    }    sub STORE {        my ($self, $index, $value) = @_;        Autom4te::Struct::_subclass_error();    }    sub FETCH {        my ($self, $index) = @_;        $self->[$index];    }    sub FETCHSIZE {        my $self = shift;        return scalar(@$self);    }    sub DESTROY { }}sub struct {    # Determine parameter list structure, one of:    #   struct( class => [ element-list ])    #   struct( class => { element-list })    #   struct( element-list )    # Latter form assumes current package name as struct name.    my ($class, @decls);    my $base_type = ref $_[1];    if ( $base_type eq 'HASH' ) {        $class = shift;        @decls = %{shift()};        _usage_error() if @_;    }    elsif ( $base_type eq 'ARRAY' ) {        $class = shift;        @decls = @{shift()};        _usage_error() if @_;    }    else {        $base_type = 'ARRAY';        $class = (caller())[0];        @decls = @_;    }    _usage_error() if @decls % 2 == 1;    # Ensure we are not, and will not be, a subclass.    my $isa = do {        no strict 'refs';        \@{$class . '::ISA'};    };    _subclass_error() if @$isa;    tie @$isa, 'Autom4te::Struct::Tie_ISA';    # Create constructor.    croak "function 'new' already defined in package $class"        if do { no strict 'refs'; defined &{$class . "::new"} };    my @methods = ();    my %refs = ();    my %arrays = ();    my %hashes = ();    my %classes = ();    my $got_class = 0;    my $out = '';    $out = "{\n  package $class;\n  use Carp;\n  sub new {\n";    $out .= "    my (\$class, \%init) = \@_;\n";    $out .= "    \$class = __PACKAGE__ unless \@_;\n";    my $cnt = 0;    my $idx = 0;    my( $cmt, $name, $type, $elem );    if( $base_type eq 'HASH' ){        $out .= "    my(\$r) = {};\n";        $cmt = '';    }    elsif( $base_type eq 'ARRAY' ){        $out .= "    my(\$r) = [];\n";    }    while( $idx < @decls ){        $name = $decls[$idx];        $type = $decls[$idx+1];        push( @methods, $name );        if( $base_type eq 'HASH' ){            $elem = "{'${class}::$name'}";        }        elsif( $base_type eq 'ARRAY' ){            $elem = "[$cnt]";            ++$cnt;            $cmt = " # $name";        }        if( $type =~ /^\*(.)/ ){            $refs{$name}++;            $type = $1;        }        my $init = "defined(\$init{'$name'}) ? \$init{'$name'} :";        if( $type eq '@' ){            $out .= "    croak 'Initializer for $name must be array reference'\n";            $out .= "        if defined(\$init{'$name'}) && ref(\$init{'$name'}) ne 'ARRAY';\n";            $out .= "    \$r->$elem = $init [];$cmt\n";            $arrays{$name}++;        }        elsif( $type eq '%' ){            $out .= "    croak 'Initializer for $name must be hash reference'\n";            $out .= "        if defined(\$init{'$name'}) && ref(\$init{'$name'}) ne 'HASH';\n";            $out .= "    \$r->$elem = $init {};$cmt\n";            $hashes{$name}++;        }        elsif ( $type eq '$') {            $out .= "    \$r->$elem = $init undef;$cmt\n";        }        elsif( $type =~ /^\w+(?:::\w+)*$/ ){            $init = "defined(\$init{'$name'}) ? \%{\$init{'$name'}} : ()";            $out .= "    croak 'Initializer for $name must be hash reference'\n";            $out .= "        if defined(\$init{'$name'}) && ref(\$init{'$name'}) ne 'HASH';\n";            $out .= "    \$r->$elem = '${type}'->new($init);$cmt\n";            $classes{$name} = $type;            $got_class = 1;        }        else{            croak "'$type' is not a valid struct element type";        }        $idx += 2;    }    $out .= "    bless \$r, \$class;\n  }\n";    # Create accessor methods.    my( $pre, $pst, $sel );    $cnt = 0;    foreach $name (@methods){        if ( do { no strict 'refs'; defined &{$class . "::$name"} } ) {            carp "function '$name' already defined, overrides struct accessor method";        }        else {            $pre = $pst = $cmt = $sel = '';            if( defined $refs{$name} ){                $pre = "\\(";                $pst = ")";                $cmt = " # returns ref";            }            $out .= "  sub $name {$cmt\n    my \$r = shift;\n";            if( $base_type eq 'ARRAY' ){                $elem = "[$cnt]";                ++$cnt;            }            elsif( $base_type eq 'HASH' ){                $elem = "{'${class}::$name'}";            }            if( defined $arrays{$name} ){                $out .= "    my \$i;\n";                $out .= "    \@_ ? (\$i = shift) : return \$r->$elem;\n";                $sel = "->[\$i]";            }            elsif( defined $hashes{$name} ){                $out .= "    my \$i;\n";                $out .= "    \@_ ? (\$i = shift) : return \$r->$elem;\n";                $sel = "->{\$i}";            }            elsif( defined $classes{$name} ){                if ( $CHECK_CLASS_MEMBERSHIP ) {                    $out .= "    croak '$name argument is wrong class' if \@_ && ! UNIVERSAL::isa(\$_[0], '$classes{$name}');\n";                }            }            $out .= "    croak 'Too many args to $name' if \@_ > 1;\n";            $out .= "    \@_ ? ($pre\$r->$elem$sel = shift$pst) : $pre\$r->$elem$sel$pst;\n";            $out .= "  }\n";        }    }    $out .= "}\n1;\n";    print $out if $print;    my $result = eval $out;    carp $@ if $@;}sub _usage_error {    confess "struct usage error";}sub _subclass_error {    croak 'struct class cannot be a subclass (@ISA not allowed)';}1; # for require__END__=head1 NAMEAutom4te::Struct - declare struct-like datatypes as Perl classes=head1 SYNOPSIS    use Autom4te::Struct;            # declare struct, based on array:    struct( CLASS_NAME => [ ELEMENT_NAME => ELEMENT_TYPE, ... ]);            # declare struct, based on hash:    struct( CLASS_NAME => { ELEMENT_NAME => ELEMENT_TYPE, ... });    package CLASS_NAME;    use Autom4te::Struct;            # declare struct, based on array, implicit class name:    struct( ELEMENT_NAME => ELEMENT_TYPE, ... );    package Myobj;    use Autom4te::Struct;            # declare struct with four types of elements:    struct( s => '$', a => '@', h => '%', c => 'My_Other_Class' );    $obj = new Myobj;               # constructor                                    # scalar type accessor:    $element_value = $obj->s;           # element value    $obj->s('new value');               # assign to element                                    # array type accessor:    $ary_ref = $obj->a;                 # reference to whole array    $ary_element_value = $obj->a(2);    # array element value    $obj->a(2, 'new value');            # assign to array element                                    # hash type accessor:    $hash_ref = $obj->h;                # reference to whole hash    $hash_element_value = $obj->h('x'); # hash element value    $obj->h('x', 'new value');        # assign to hash element                                    # class type accessor:    $element_value = $obj->c;           # object reference    $obj->c->method(...);               # call method of object    $obj->c(new My_Other_Class);        # assign a new object=head1 DESCRIPTIONC<Autom4te::Struct> exports a single function, C<struct>.Given a list of element names and types, and optionallya class name, C<struct> creates a Perl 5 class that implementsa "struct-like" data structure.The new class is given a constructor method, C<new>, for creatingstruct objects.Each element in the struct data has an accessor method, which isused to assign to the element and to fetch its value.  Thedefault accessor can be overridden by declaring a C<sub> of thesame name in the package.  (See Example 2.)Each element's type can be scalar, array, hash, or class.