[p5sagit/p5-mst-13.2.git] / t / comp / fold.t

#!./perl

BEGIN {
    chdir 't';
    @INC = '../lib';
    require './test.pl';
}
use strict;
use warnings;

plan (8);

# Historically constant folding was performed by evaluating the ops, and if
# they threw an exception compilation failed. This was seen as buggy, because
# even illegal constants in unreachable code would cause failure. So now
# illegal expressions are reported at runtime, if the expression is reached,
# making constant folding consistent with many other languages, and purely an
# optimisation rather than a behaviour change.

my $a;
$a = eval '$b = 0/0 if 0; 3';
is ($a, 3);
is ($@, "");

my $b = 0;
$a = eval 'if ($b) {return sqrt -3} 3';
is ($a, 3);
is ($@, "");

$a = eval q{
	$b = eval q{if ($b) {return log 0} 4};
 	is ($b, 4);
	is ($@, "");
	5;
};
is ($a, 5);
is ($@, "");
Commit	Line	Data
a5871da3	1	#!./perl
	2
	3	BEGIN {
	4	chdir 't';
	5	@INC = '../lib';
	6	require './test.pl';
	7	}
	8	use strict;
	9	use warnings;
	10
	11	plan (8);
	12
	13	# Historically constant folding was performed by evaluating the ops, and if
	14	# they threw an exception compilation failed. This was seen as buggy, because
	15	# even illegal constants in unreachable code would cause failure. So now
	16	# illegal expressions are reported at runtime, if the expression is reached,
	17	# making constant folding consistent with many other languages, and purely an
	18	# optimisation rather than a behaviour change.
	19
	20	my $a;
	21	$a = eval '$b = 0/0 if 0; 3';
	22	is ($a, 3);
	23	is ($@, "");
	24
	25	my $b = 0;
	26	$a = eval 'if ($b) {return sqrt -3} 3';
	27	is ($a, 3);
	28	is ($@, "");
	29
	30	$a = eval q{
	31	$b = eval q{if ($b) {return log 0} 4};
	32	is ($b, 4);
	33	is ($@, "");
	34	5;
	35	};
	36	is ($a, 5);
	37	is ($@, "");
	38