state $foo if 0 shouldn't warn. Spotted by Abigail.

[p5sagit/p5-mst-13.2.git] / t / op / state.t

diff --git a/t/op/state.t b/t/op/state.t
index 987cf6e..f7db804 100644 (file)
--- a/t/op/state.t
+++ b/t/op/state.t
@@ -1,4 +1,5 @@
 #!./perl -w
+# tests state variables
 
 BEGIN {
     chdir 't' if -d 't';
@@ -7,32 +8,41 @@ BEGIN {
 }
 
 use strict;
+use feature "state";
 
-plan tests => 19;
+plan tests => 38;
 
 ok( ! defined state $uninit, q(state vars are undef by default) );
 
+# basic functionality
+
 sub stateful {
     state $x;
     state $y = 1;
     my $z = 2;
-    return ($x++, $y++, $z++);
+    state ($t) //= 3;
+    return ($x++, $y++, $z++, $t++);
 }
 
-my ($x, $y, $z) = stateful();
+my ($x, $y, $z, $t) = stateful();
 is( $x, 0, 'uninitialized state var' );
 is( $y, 1, 'initialized state var' );
 is( $z, 2, 'lexical' );
+is( $t, 3, 'initialized state var, list syntax' );
 
-($x, $y, $z) = stateful();
+($x, $y, $z, $t) = stateful();
 is( $x, 1, 'incremented state var' );
 is( $y, 2, 'incremented state var' );
 is( $z, 2, 'reinitialized lexical' );
+is( $t, 4, 'incremented state var, list syntax' );
 
-($x, $y, $z) = stateful();
+($x, $y, $z, $t) = stateful();
 is( $x, 2, 'incremented state var' );
 is( $y, 3, 'incremented state var' );
 is( $z, 2, 'reinitialized lexical' );
+is( $t, 5, 'incremented state var, list syntax' );
+
+# in a nested block
 
 sub nesting {
     state $foo = 10;
@@ -50,6 +60,8 @@ is( $y, 13, 'inner state var' );
 is( $x, 12, 'outer state var' );
 is( $y, 14, 'inner state var' );
 
+# in a closure
+
 sub generator {
     my $outer;
     # we use $outer to generate a closure
@@ -63,3 +75,86 @@ my $f2 = generator();
 is( $f2->(), 1, 'generator 2' );
 is( $f1->(), 3, 'generator 1 again' );
 is( $f2->(), 2, 'generator 2 once more' );
+
+# with ties
+{
+    package countfetches;
+    our $fetchcount = 0;
+    sub TIESCALAR {bless {}};
+    sub FETCH { ++$fetchcount; 18 };
+    tie my $y, "countfetches";
+    sub foo { state $x = $y; $x++ }
+    ::is( foo(), 18, "initialisation with tied variable" );
+    ::is( foo(), 19, "increments correctly" );
+    ::is( foo(), 20, "increments correctly, twice" );
+    ::is( $fetchcount, 1, "fetch only called once" );
+}
+
+# state variables are shared among closures
+
+sub gen_cashier {
+    my $amount = shift;
+    state $cash_in_store = 0;
+    return {
+       add => sub { $cash_in_store += $amount },
+       del => sub { $cash_in_store -= $amount },
+       bal => sub { $cash_in_store },
+    };
+}
+
+gen_cashier(59)->{add}->();
+gen_cashier(17)->{del}->();
+is( gen_cashier()->{bal}->(), 42, '$42 in my drawer' );
+
+# stateless assignment to a state variable
+
+sub stateless {
+    state $reinitme = 42;
+    ++$reinitme;
+}
+is( stateless(), 43, 'stateless function, first time' );
+is( stateless(), 44, 'stateless function, second time' );
+
+# array state vars
+
+sub stateful_array {
+    state @x;
+    push @x, 'x';
+    return $#x;
+}
+
+my $xsize = stateful_array();
+is( $xsize, 0, 'uninitialized state array' );
+
+$xsize = stateful_array();
+is( $xsize, 1, 'uninitialized state array after one iteration' );
+
+# hash state vars
+
+sub stateful_hash {
+    state %hx;
+    return $hx{foo}++;
+}
+
+my $xhval = stateful_hash();
+is( $xhval, 0, 'uninitialized state hash' );
+
+$xhval = stateful_hash();
+is( $xhval, 1, 'uninitialized state hash after one iteration' );
+
+# Recursion
+
+sub noseworth {
+    my $level = shift;
+    state $recursed_state = 123;
+    is($recursed_state, 123, "state kept through recursion ($level)");
+    noseworth($level - 1) if $level;
+}
+noseworth(2);
+
+# Assignment return value
+
+sub pugnax { my $x = state $y = 42; $y++; $x; }
+
+is( pugnax(), 42, 'scalar state assignment return value' );
+is( pugnax(), 43, 'scalar state assignment return value' );