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Add is_inf and is_nan functions to builtin:: #22059

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Add is_inf and is_nan functions to builtin:: #22059

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30 changes: 30 additions & 0 deletions builtin.c
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Original file line number Diff line number Diff line change
Expand Up @@ -99,6 +99,20 @@ XS(XS_builtin_inf)
XSRETURN_NV(NV_INF);
}

XS(XS_builtin_is_inf);
XS(XS_builtin_is_inf)
{
dXSARGS;
SV *val = ST(0);
if(items != 1)
croak_xs_usage(cv, "val");
SvGETMAGIC(val);
if(SvNOK(val) && Perl_isinf(SvNV(val)))
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The NOK check seems non-perlish to me, it also breaks overloads:

tony@venus:.../git/perl6$ ./perl -Ilib ../22059.pl 
Built-in function 'builtin::inf' is experimental at ../22059.pl line 6.
Built-in function 'builtin::is_inf' is experimental at ../22059.pl line 11.
Built-in function 'builtin::is_inf' is experimental at ../22059.pl line 13.

1

1
tony@venus:.../git/perl6$ cat ../22059.pl
use v5.38;
use builtin qw(is_inf inf);
use POSIX();

package Foo {
  use overload '0+' => sub { inf };
}

my $x = bless {}, "Foo";

say is_inf($x);
say POSIX::isinf($x);
say is_inf("Inf");
say POSIX::isinf("Inf");

XSRETURN_YES;
else
XSRETURN_NO;
}

XS(XS_builtin_nan);
XS(XS_builtin_nan)
{
Expand All @@ -109,6 +123,20 @@ XS(XS_builtin_nan)
XSRETURN_NV(NV_NAN);
}

XS(XS_builtin_is_nan);
XS(XS_builtin_is_nan)
{
dXSARGS;
SV *val = ST(0);
if(items != 1)
croak_xs_usage(cv, "val");
SvGETMAGIC(val);
if(SvNOK(val) && Perl_isnan(SvNV(val)))
XSRETURN_YES;
else
XSRETURN_NO;
}

enum {
BUILTIN_CONST_FALSE,
BUILTIN_CONST_TRUE,
Expand Down Expand Up @@ -550,6 +578,8 @@ static const struct BuiltinFuncDescriptor builtins[] = {

/* unary functions */
{ "is_bool", NO_BUNDLE, &XS_builtin_func1_scalar, &ck_builtin_func1, OP_IS_BOOL, true },
{ "is_inf", NO_BUNDLE, &XS_builtin_is_inf, &ck_builtin_func1, 0, true },
{ "is_nan", NO_BUNDLE, &XS_builtin_is_nan, &ck_builtin_func1, 0, true },
{ "weaken", SHORTVER(5,39), &XS_builtin_func1_void, &ck_builtin_func1, OP_WEAKEN, false },
{ "unweaken", SHORTVER(5,39), &XS_builtin_func1_void, &ck_builtin_func1, OP_UNWEAKEN, false },
{ "is_weak", SHORTVER(5,39), &XS_builtin_func1_scalar, &ck_builtin_func1, OP_IS_WEAK, false },
Expand Down
23 changes: 22 additions & 1 deletion lib/builtin.pm
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@@ -1,4 +1,4 @@
package builtin 0.014;
package builtin 0.015;

use strict;
use warnings;
Expand Down Expand Up @@ -154,6 +154,17 @@ This function is currently B<experimental>.

Returns the floating-point infinity value.

=head2 is_inf

$inf = is_inf($val);

This function is currently B<experimental>.

Returns true when given the postive or negative floating-point infinity values,
false if not. A floating-point infinity value can be generated when certain
floating-point operations are performed, based on platform-specific floating
point handling.

=head2 nan

$num = nan;
Expand All @@ -162,6 +173,16 @@ This function is currently B<experimental>.

Returns the floating-point "Not-a-Number" value.

=head2 is_nan

$nan = is_nan($val);

This function is currently B<experimental>.

Returns true when given the floating-point "Not-A-Number" value, false if not.
The floating-point NaN value can be generated when certain floating-point
operations are performed, based on platform-specific floating point handling.

=head2 weaken

weaken($ref);
Expand Down
36 changes: 34 additions & 2 deletions lib/builtin.t
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Expand Up @@ -51,15 +51,17 @@ package FetchStoreCounter {
is(prototype(\&builtin::is_bool), '$', 'is_bool prototype');
}

# float constants
# floats
{
use builtin qw( inf nan );
use builtin qw( inf nan is_inf is_nan is_bool );

ok(inf, 'inf is true');
ok(inf > 1E10, 'inf is bigger than 1E10');
ok(inf == inf, 'inf is equal to inf');
ok(inf == inf + 1, 'inf is equal to inf + 1');

ok(inf != -inf, 'inf is not equal to -inf');

# Invoke the real XSUB
my $inf = ( \&builtin::inf )->();
ok($inf == $inf + 1, 'inf returned by real xsub');
Expand All @@ -68,6 +70,36 @@ package FetchStoreCounter {

my $nan = ( \&builtin::nan )->();
ok($nan != $nan, 'NaN returned by real xsub');

# Test is_inf and is_nan from various sources
ok(is_inf(inf), 'is_inf(inf) is true');
ok(is_inf(-inf), 'is_inf(-inf) is true');
ok(is_nan(nan), 'is_nan(nan) is true');

ok(is_inf($inf), 'is_inf(inf) from xsub is true');
ok(is_inf($inf), 'is_inf(inf) from xsub is true');
ok(is_nan($nan), 'is_nan(nan) from xsub is true');

ok(is_nan(1*(inf-inf)), 'is_nan is true for calculated nan');
ok(is_inf(9**9**9), 'is_inf is true for calculated inf');

# Try some obvious variations that should fail.
ok(!is_nan($inf), 'is_nan(inf) is false');
ok(!is_inf($nan), 'is_inf(nan) is false');

# Strings that look like stringified floats should not pass
ok(!is_nan('NaN'), 'is_nan(\'NaN\') is false');
ok(!is_inf('inf'), 'is_inf(\'inf\') is false');

ok(!is_nan(0), 'is_nan(0) is false');
ok(!is_inf(0), 'is_inf(0) is false');

ok(!is_nan(0.0), 'is_nan(0.0) is false');
ok(!is_inf(0.0), 'is_inf(0.0) is false');

# Ensure that is_nan and is_inf return real bools
ok(is_bool(is_nan($nan)), 'is_nan returns bool');
ok(is_bool(is_inf($inf)), 'is_inf returns bool');
}

# weakrefs
Expand Down