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[perl5.git] / t / op / state.t
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952306ac 1#!./perl -w
ea84231e 2# tests state variables
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3
4BEGIN {
5 chdir 't' if -d 't';
6 @INC = '../lib';
7 require './test.pl';
8}
9
10use strict;
712d05cf 11use feature "state";
952306ac 12
ea84231e 13plan tests => 26;
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14
15ok( ! defined state $uninit, q(state vars are undef by default) );
16
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17# basic functionality
18
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19sub stateful {
20 state $x;
21 state $y = 1;
22 my $z = 2;
23 return ($x++, $y++, $z++);
24}
25
26my ($x, $y, $z) = stateful();
27is( $x, 0, 'uninitialized state var' );
28is( $y, 1, 'initialized state var' );
29is( $z, 2, 'lexical' );
30
31($x, $y, $z) = stateful();
32is( $x, 1, 'incremented state var' );
33is( $y, 2, 'incremented state var' );
34is( $z, 2, 'reinitialized lexical' );
35
36($x, $y, $z) = stateful();
37is( $x, 2, 'incremented state var' );
38is( $y, 3, 'incremented state var' );
39is( $z, 2, 'reinitialized lexical' );
40
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41# in a nested block
42
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43sub nesting {
44 state $foo = 10;
45 my $t;
46 { state $bar = 12; $t = ++$bar }
47 ++$foo;
48 return ($foo, $t);
49}
50
51($x, $y) = nesting();
52is( $x, 11, 'outer state var' );
53is( $y, 13, 'inner state var' );
54
55($x, $y) = nesting();
56is( $x, 12, 'outer state var' );
57is( $y, 14, 'inner state var' );
58
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59# in a closure
60
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61sub generator {
62 my $outer;
63 # we use $outer to generate a closure
64 sub { ++$outer; ++state $x }
65}
66
67my $f1 = generator();
68is( $f1->(), 1, 'generator 1' );
69is( $f1->(), 2, 'generator 1' );
70my $f2 = generator();
71is( $f2->(), 1, 'generator 2' );
72is( $f1->(), 3, 'generator 1 again' );
73is( $f2->(), 2, 'generator 2 once more' );
5d1e1362 74
ea84231e 75# with ties
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76{
77 package countfetches;
78 our $fetchcount = 0;
79 sub TIESCALAR {bless {}};
80 sub FETCH { ++$fetchcount; 18 };
81 tie my $y, "countfetches";
82 sub foo { state $x = $y; $x++ }
83 ::is( foo(), 18, "initialisation with tied variable" );
84 ::is( foo(), 19, "increments correctly" );
85 ::is( foo(), 20, "increments correctly, twice" );
86 ::is( $fetchcount, 1, "fetch only called once" );
87}
aa2c6373 88
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89# state variables are shared among closures
90
91sub gen_cashier {
92 my $amount = shift;
93 state $cash_in_store = 0;
94 return {
95 add => sub { $cash_in_store += $amount },
96 del => sub { $cash_in_store -= $amount },
97 bal => sub { $cash_in_store },
98 };
99}
100
101gen_cashier(59)->{add}->();
102gen_cashier(17)->{del}->();
103is( gen_cashier()->{bal}->(), 42, '$42 in my drawer' );
104
105# stateless assignment to a state variable
106
aa2c6373 107sub stateless {
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108 (state $reinitme) = 42;
109 ++$reinitme;
110}
111is( stateless(), 43, 'stateless function, first time' );
112is( stateless(), 43, 'stateless function, second time' );