############################################################################

# Copyright (c) 1998 Enno Derksen

# All rights reserved.

# This program is free software; you can redistribute it and/or modify it

# under the same terms as Perl itself. 

############################################################################

#

# Extra functionality that is not part of the XQL spec

#

package XML::XQL;

use strict;

BEGIN 

{

    die "don't use/require XML::XQL::Plus, either use/require XML::XQL or XML::XQL::Strict" unless $XML::XQL::Included;

};

defineComparisonOperators

(

 "=~"		=> \&XML::XQL::match_oper,

 "!~"		=> \&XML::XQL::no_match_oper,

 "match"	=> \&XML::XQL::match_oper,

 "no_match"	=> \&XML::XQL::no_match_oper,

 "isa"		=> \&XML::XQL::isa_oper,

 "can"		=> \&XML::XQL::can_oper,

);

sub match_oper

{

    my ($node, $expr) = @_;

    return [] if isEmptyList ($node);

#?? can this happen?

    my $str = $node->xql_toString;

    $expr = prepareRvalue ($expr->solve ([$node]));

    return [] if isEmptyList ($expr);

#?? can this happen?

    $expr = $expr->xql_toString;

    croak "bad search pattern '$expr' for =~" unless $expr =~ m!^\s*[m/]!o;

    my $res = eval "\$str =~ $expr";

    croak "bad search pattern '$expr' for =~ operator: $@"  if ($@);

    $res;

}

sub no_match_oper

{

    my ($node, $expr) = @_;

    return [] if isEmptyList ($node);

#?? can this happen?

    my $str = $node->xql_toString;

    $expr = prepareRvalue ($expr->solve ([$node]));

    return [] if isEmptyList ($expr);

#?? can this happen?

    $expr = $expr->xql_toString;

    croak "bad search pattern '$expr' for !~" unless $expr =~ m!^\s*[m/]!o;

    my $res = eval "\$str !~ $expr";

    croak "bad search pattern '$expr' for !~ operator: $@"  if ($@);

    $res;

}

sub isa_oper

{

    my ($node, $expr) = @_;

    return [] if isEmptyList ($node);

#?? can this happen?

    $expr = prepareRvalue ($expr->solve ([$node]));

    return [] if isEmptyList ($expr);

#?? can this happen?

    $expr = $expr->xql_toString;

    # Expand "number" to "XML::XQL::Number" etc.

    $expr = expandType ($expr);

#?? I don't think empty lists are possible here. If so, add "[]" as expr

    ref($node) and $node->isa ($expr);

}

#

# Not sure how useful this is, unless it supports XQL functions/methods...

#

sub can_oper

{

    my ($node, $expr) = @_;

    return [] if isEmptyList ($node);

#?? can this happen?

    $expr = prepareRvalue ($expr->solve ([$node]));

    return [] if isEmptyList ($expr);

#?? can this happen?

    $expr = $expr->xql_toString;

    ref ($node) and $node->can ($expr);

}

sub once

{

    my ($context, $list, $expr) = @_;

    $expr->solve ($context, $list);

}

sub xql_eval

{

    my ($context, $list, $query, $type) = @_;

#   return [] if @$list == 0;

    $query = toList ($query->solve ($context, $list));

    return [] unless @$query;

    if (defined $type)

    {

	$type = prepareRvalue ($type->solve ($context, $list));

	$type = isEmptyList ($type) ? "Text" : $type->xql_toString;

	# Expand "number" to "XML::XQL::Number" etc.

	$type = expandType ($type);

    }

    else

    {

	$type = "XML::XQL::Text";

    }

    my @result = ();

    for my $val (@$query)

    {

	$val = $val->xql_toString;

	$val = eval $val;

#print "eval result=$val\n";

#?? check result?

	push @result, eval "new $type (\$val)" if defined $val;

    }

    \@result;

}

sub subst

{

    my ($context, $list, $query, $expr, $repl, $mod, $mode) = @_;

#?? not sure?

    return [] if @$list == 0;

    $expr = prepareRvalue ($expr->solve ($context, $list));

    return [] if isEmptyList ($expr);

    $expr = $expr->xql_toString;

    $repl = prepareRvalue ($repl->solve ($context, $list));

    return [] if isEmptyList ($repl);

    $repl = $repl->xql_toString;

    if (defined $mod)

    {

	$mod = prepareRvalue ($mod->solve ($context, $list));

	$mod = isEmptyList ($mod) ? "" : $mod->xql_toString;

    }

    if (defined $mode)

    {

	$mode = prepareRvalue ($mode->solve ($context, $list));

	$mode = isEmptyList ($mode) ? 0 : $mode->xql_toString;

    }

    else

    {

	$mode = 0;	# default mode: use textBlocks for Elements

    }

    my @result = ();

    my $nodes = toList ($query->solve ($context, $list));

    for my $node (@$nodes)

    {

	if ($mode == 0 && $node->xql_nodeType == 1)	# 1: Element node

	{

	    # For Element nodes, replace text in consecutive text blocks

	    # Note that xql_rawtextBlocks, returns the blocks in reverse order,

	    # so that the indices of nodes within previous blocks don't need

	    # to be adjusted when a replacement occurs.

	    my $block_matched = 0;

	    BLOCK: for my $block ($node->xql_rawTextBlocks)

	    {

		my $str = $block->[2];

		my $result = eval "\$str =~ s/\$expr/\$repl/$mod";

		croak "bad subst expression s/$expr/$repl/$mod: $@" if ($@);

		next BLOCK unless $result;

		$block_matched++;

		$node->xql_replaceBlockWithText ($block->[0], $block->[1], $str);

	    }

	    # Return the input parameter only if a substitution occurred

	    push @result, $node if $block_matched;

	}

	else

	{

	    my $str = $node->xql_toString;

	    next unless defined $str;

	    my $result = eval "\$str =~ s/\$expr/\$repl/$mod";

	    croak "bad subst expression s/$expr/$repl/$mod: $@" if ($@);

	    next unless $result;

#print "result=$result for str[$str] =~ s/$expr/$repl/$mod\n";

	    # Return the input parameter only if a substitution occurred

	    $node->xql_setValue ($str);

	    push @result, $node;

	}

	# xql_setValue will actually change the value of the node for an Attr,

	# Text, CDataSection, EntityRef or Element

    }

    \@result;

}

#?? redo match - what should it return?

sub match

{

    my ($context, $list, $query, $repl, $mod) = @_;

    return [] if @$list == 0;

    $query = prepareRvalue ($query->solve ($context, $list));

    return [] if isEmptyList ($query);

    $query = $query->xql_toString;

    if (defined $mod)

    {

	$mod = prepareRvalue ($mod->solve ($context, $list));

	$mod = isEmptyList ($mod) ? "" : $mod->xql_toString;

    }

    my $str = $list->[0]->xql_toString;

    return [] unless defined $str;

    my (@matches) = ();

    eval "\@matches = (\$str =~ /\$query/$mod)";

    croak "bad match expression m/$query/$mod" if ($@);

#?? or should I map undef to XML::XQL::Text("") ?

    @matches = map { defined($_) ? new XML::XQL::Text ($_) : [] } @matches;

    \@matches;

}

sub xql_map

{

    my ($context, $list, $query, $code) = @_;

#?? not sure?

    return [] if @$list == 0;

    $code = prepareRvalue ($code->solve ($context, $list));

    return [] if isEmptyList ($code);

    $code = $code->xql_toString;

    my @result = ();

    my $nodes = toList ($query->solve ($context, $list));

    for my $node (@$nodes)

    {

	my $str = $node->xql_toString;

	next unless defined $str;

	my (@mapresult) = ($str);

#?? NOTE: the $code should

	eval "\@mapresult = map { $code } (\$str)";

	croak "bad map expression '$code' ($@)" if ($@);

	# Return the input parameter only if a change occurred

	next unless $mapresult[0] eq $str;

	# xql_setValue will actually change the value of the node for an Attr,

	# Text, CDataSection, EntityRef or Element

	$node->xql_setValue ($str);

	push @result, $node;

    }

    \@result;

}

sub xql_new

{

    my ($type, @arg) = @_;

    # Expand "number" to "XML::XQL::Number" etc.

    $type = expandType ($type);

    my $obj = eval "new $type (\@arg)";

    $@ ? [] : $obj;	# return empty list on exception

}

my $DOM_PARSER;	# used by xql_document (below)

sub setDocParser

{

    $DOM_PARSER = shift;

}

sub xql_document

{

    my ($docname) = @_;

    my $parser = $DOM_PARSER ||= new XML::DOM::Parser;

    my $doc;

    eval

    {

	$doc = $parser->parsefile ($docname);

    };

    if ($@)

    {

	warn "xql_document: could not read XML file [$docname]: $@";

    }

    return defined $doc ? $doc : [];

}

#----------- XQL+ methods --------------------------------------------

sub DOM_nodeType

{

    my ($context, $list) = @_;

    return [] if @$list == 0;

    new XML::XQL::Number ($list->[0]->xql_DOM_nodeType, $list->[0]);

}

#----------- Perl Builtin Functions ----------------------------------

# Note that certain functions (like mkdir) are not considered "constant"

# because we don't want their invocation values cached. (We want the

# function to be called every time the Invocation is solved/evaluated.)

my %PerlFunc =

(

 # Format: 

 #  "funcName", => [ARGCOUNT, RETURN_TYPE [, CONSTANT = 0, [QUERY_ARG = 0]]]

 #-------- Arithmetic Functions

 "abs" => [1, "Number", 1], 

 "atan2" => [2, "Number", 1, -1], 

 "cos" => [1, "Number", 1], 

 "exp" => [1, "Number", 1], 

 "int" => [1, "Number", 1], 

 "log" => [1, "Number", 1], 

 "rand" => [[0, 1], "Number", 0, -1], 

 "sin" => [1, "Number", 1], 

 "sqrt" => [1, "Number", 1], 

 "srand" => [[0, 1], "Number", 0, -1], 

 "time" => [0, "Number", 0, -1], 

 #-------- Conversion Functions

 "chr" => [1, "Text", 1], 

# "gmtime" => [1, "List of Number", 1], 

 "hex" => [1, "Number", 1], 

# "localtime" => [1, "List of Number", 1], 

 "oct" => [1, "Number", 1], 

 "ord" => [1, "Text", 1], 

 "vec" => [3, "Number", 1], 

 "pack" => [[1, -1], "Text", 1, -1], #?? how should this work??

# "unpack" => [2, "List of ?", 1], 

 #-------- String Functions

 "chomp" => [1, "Text", 1], 

 "chop" => [1, "Text", 1], 

 "crypt" => [2, "Text", 1], 

 "lindex" => [[2, 3], "Number", 1],	# "index" is already taken by XQL

 "length" => [1, "Number", 1], 

 "lc" => [1, "Text", 1], 

 "lcfirst" => [1, "Text", 1], 

 "quotemeta" => [1, "Text", 1], 

 "rindex" => [[2, 3], "Number", 1], 

 "substr" => [[2, 3], "Text", 1], 

 "uc" => [1, "Text", 1], 

 "ucfirst" => [1, "Text", 1], 

 "reverse" => [1, "Text", 1], 

 "sprintf" => [[1, -1], "Text", 1, -1],

 #-------- Array Functions

 "join" => [[1, -1], "Text", 1], 

# "split" => [[2, 3], "List of Text", 1], 

 #-------- File Functions

 "chmod" => [2, "Boolean", 0, 1],

 "chown" => [3, "Boolean", 0, 2],

 "link" => [2, "Number", 0, -1],		#?? no return value

# "lstat" => [1, "List of Number"], 

 "mkdir" => [2, "Boolean"],		#?? or is 1 arg also allowed?

 "readlink" => [1, "Text"], 

 "rename" => [2, "Boolean", 0, -1],

 "rmdir" => [1, "Boolean"],

# "stat" => [1, "List of Number"], 

 "symlink" => [2, "Boolean", 0, -1],

 "unlink" => [1, "Boolean"],

 "utime" => [3, "Boolean", 0, 2],

 "truncate" => [2, "Number"],		#?? no return value

 #-------- System Interaction

 "exit" => [[0, 1], "Number"], 

# "glob" => [1, "List of Text"], 

 "system" => [[1, -1], "Number", 0, -1], 

# "times" => [0, "List of Number"],

 #-------- Miscellaneous

 "defined" => [1, "Boolean"],	# is this useful??

 "dump" => [[0, 1], "Number", 0, -1], 

 "ref" => [1, "Text"],

);

#?? die, warn, croak (etc.), 

#?? file test (-X), tr// (same as y//)

#?? array functions, sort

# Generate wrapper for Perl builtin function on the fly

sub generatePerlWrapper

{

    my ($name) = @_;

    my $args = $PerlFunc{$name};

    return undef unless defined $args;	# not found

    my ($argCount, $returnType, $const, $queryArg) = @$args;

    my $funcName = $name;

    if ($name eq "lindex")	# "index" is already taken

    {

	$funcName = "index";

    }    

    generateFunction ($name, $funcName, $returnType, $argCount, 0, $const, 

		      $queryArg);

    $Func{$name};

}

#?? Inline functions, do they make sense? E.g. 'elem!sub("code", "arg1")'

#?? Normally, user should use defineFunction, but if most of them have

#?? a lot of common code, I could provide the pre- and post-code.

#?? After processing the user-supplied code block, how should I convert the

#?? user's result back to an Invocation result. E.g. do I get a single value

#?? or a list back?

defineFunction ("eval",  \&XML::XQL::xql_eval,		[1, 2]);

defineFunction ("subst", \&XML::XQL::subst,		[3, 5], 1);

defineFunction ("s",	 \&XML::XQL::subst,		[3, 5], 1);

defineFunction ("match", \&XML::XQL::match,		[1, 2]);

defineFunction ("m",     \&XML::XQL::match,		[1, 2]);

defineFunction ("map",   \&XML::XQL::xql_map,		2,      1);

defineFunction ("once",  \&XML::XQL::once,		1,      1);

defineMethod ("DOM_nodeType", \&XML::XQL::DOM_nodeType, 0, 0);

generateFunction ("new", "XML::XQL::xql_new", "*", [1, -1], 1, 0, 1);

generateFunction ("document", "XML::XQL::xql_document", "*", 1, 1, 0, 0);

# doc() is an alias for document() 

defineFunction ("doc", \&XML::XQL::xql_wrap_document, 1, 1);

#------------------------------------------------------------------------------

# The following functions were found in the XPath spec.

# Found in XPath but not (yet) implemented in XML::XQL:

# - type casting (string, number, boolean) - Not sure if needed...

#   Note that string() converts booleans to 'true' and 'false', but our

#   internal type casting converts it to perl values '0' and '1'...

# - math (+,-,*,mod,div) - Use eval() for now

# - last(), position() - Similar to end() and index() except they're 1-based

# - local-name(node-set?), namespace-uri(node-set?)

# - name(node-set?) - Can we pass a node-set in XQL?

# - lang(string)

sub xpath_concat	{ join ("", @_) }

sub xpath_starts_with	{ $_[0] =~ /^\Q$_[1]\E/ }

# ends-with is not part of XPath

sub xpath_ends_with	{ $_[0] =~ /\Q$_[1]\E$/ }

sub xpath_contains	{ $_[0] =~ /\Q$_[1]\E/ }

# The following methods don't know about NaN, +/-Infinity or -0.

sub xpath_floor		{ use POSIX; POSIX::floor ($_[0]) }

sub xpath_ceiling	{ use POSIX; POSIX::ceil ($_[0]) }

sub xpath_round  	{ use POSIX; POSIX::floor ($_[0] + 0.5) }

# Note that the start-index is 1-based in XPath

sub xpath_substring	

{ 

    defined $_[2] ? substr ($_[0], $_[1] - 1, $_[2]) 

		  : substr ($_[0], $_[1] - 1) 

}

sub xpath_substring_before	

{

    my $i = index ($_[0], $_[1]); 

    $i == -1 ? undef : substr ($_[0], 0, $i) 

}

sub xpath_substring_after	

{ 

    my $i = index ($_[0], $_[1]);

    $i == -1 ? undef : substr ($_[0], $i + length($_[1])) 

}

# Note that d,c,s are tr/// modifiers. Also can't use open delimiters i.e. {[(<

my @TR_DELIMITERS = split //, "/!%^&*)-_=+|~]}'\";:,.>/?abefghijklmnopqrtuvwxyz";

sub xpath_translate

{

    my ($str, $from, $to) = @_;

    my $delim;

    for my $d (@TR_DELIMITERS)

    {

	if (index ($from, $d) == -1 && index ($to, $d) == -1)

	{

	    $delim = $d;

	    last;

	}

    }

    die "(xpath_)translate: can't find suitable 'tr' delimiter"