make function arguments readonly

2 files changed, 37 insertions, 0 deletions

diff --git a/t/basic.t b/t/basic.t
index 080c2cf..2b2104f 100644
--- a/t/basic.t
+++ b/t/basic.t
@@ -29,4 +29,9 @@ is(sum(1, 2, 3, 4), 10);
 
 ok(exists $Foo::{foo});
 
+fun empty ($bar, $baz) { }
+
+is(scalar(empty(1, 2)), undef);
+is_deeply([empty(1, 2)], []);
+
 done_testing;
diff --git a/t/readonly.t b/t/readonly.t
new file mode 100644
index 0000000..f0b82ea
--- /dev/null
+++ b/t/readonly.t
@@ -0,0 +1,32 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use Test::More;
+
+use Fun;
+
+my $thing = 1;
+
+fun foo ($bar) { $bar = 1 }
+
+ok(!eval { foo(); 1 });
+ok(!eval { foo(1); 1 });
+ok(!eval { foo($thing); 1 });
+ok(!eval { foo($thing + 1); 1 });
+
+fun bar ($baz) { $baz }
+
+ok(eval { bar(); 1 });
+ok(eval { bar(1); 1 });
+ok(eval { bar($thing); 1 });
+ok(eval { bar($thing + 1); 1 });
+
+ok(eval { $thing = 2; 1 });
+is($thing, 2);
+
+fun baz ($quux) { $_[0] = 1 }
+
+ok(eval { baz($thing); 1 });
+is($thing, 1);
+
+done_testing;