ljr/wcmtools/s2/S2/NodeAssignExpr.pm

102 lines
2.3 KiB
Perl
Executable File

#!/usr/bin/perl
#
package S2::NodeAssignExpr;
use strict;
use S2::Node;
use S2::NodeCondExpr;
use vars qw($VERSION @ISA);
$VERSION = '1.0';
@ISA = qw(S2::Node);
sub new {
my ($class, $n) = @_;
my $node = new S2::Node;
bless $node, $class;
}
sub canStart {
my ($class, $toker) = @_;
S2::NodeCondExpr->canStart($toker);
}
sub parse {
my ($class, $toker) = @_;
my $n = new S2::NodeAssignExpr;
$n->{'lhs'} = parse S2::NodeCondExpr $toker;
$n->addNode($n->{'lhs'});
if ($toker->peek() == $S2::TokenPunct::ASSIGN) {
$n->{'op'} = $toker->peek();
$n->eatToken($toker);
} else {
return $n->{'lhs'};
}
$n->{'rhs'} = parse S2::NodeAssignExpr $toker;
$n->addNode($n->{'rhs'});
return $n;
}
sub getType {
my ($this, $ck, $wanted) = @_;
my $lt = $this->{'lhs'}->getType($ck, $wanted);
my $rt = $this->{'rhs'}->getType($ck, $lt);
if ($lt->isReadOnly()) {
S2::error($this, "Left-hand side of assignment is a read-only value.");
}
if (! $this->{'lhs'}->isa('S2::NodeTerm') ||
! $this->{'lhs'}->isLValue()) {
S2::error($this, "Left-hand side of assignment must be an lvalue.");
}
if ($this->{'lhs'}->isBuiltinProperty($ck)) {
S2::error($this, "Can't assign to built-in properties.");
}
return $lt if $ck->typeIsa($rt, $lt);
# types don't match, but maybe class for left hand side has
# a constructor which takes a string.
if ($rt->equals($S2::Type::STRING) && $ck->isStringCtor($lt)) {
$rt = $this->{'rhs'}->getType($ck, $lt); # FIXME: can remove this line?
return $lt if $lt->equals($rt);
}
S2::error($this, "Can't assign type " . $rt->toString . " to " . $lt->toString);
}
sub asS2 {
my ($this, $o) = @_;
$this->{'lhs'}->asS2($o);
if ($this->{'op'}) {
$o->write(" = ");
$this->{'rhs'}->asS2($o);
}
}
sub asPerl {
my ($this, $bp, $o) = @_;
die "INTERNAL ERROR: no op?" unless $this->{'op'};
$this->{'lhs'}->asPerl($bp, $o);
my $need_notags = $bp->untrusted() &&
$this->{'lhs'}->isProperty() &&
$this->{'lhs'}->getType()->equals($S2::Type::STRING);
$o->write(" = ");
$o->write("S2::notags(") if $need_notags;
$this->{'rhs'}->asPerl($bp, $o);
$o->write(")") if $need_notags;
}