Commit | Line | Data |
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1 | #!./perl |
2 | |
3 | BEGIN { |
4 | chdir 't'; |
5 | @INC = '../lib'; |
6 | require './test.pl'; |
7 | } |
8 | use strict; |
9 | use warnings; |
10 | |
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11 | plan (13); |
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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 | |
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20 | |
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21 | my $a; |
22 | $a = eval '$b = 0/0 if 0; 3'; |
23 | is ($a, 3); |
24 | is ($@, ""); |
25 | |
26 | my $b = 0; |
27 | $a = eval 'if ($b) {return sqrt -3} 3'; |
28 | is ($a, 3); |
29 | is ($@, ""); |
30 | |
31 | $a = eval q{ |
32 | $b = eval q{if ($b) {return log 0} 4}; |
33 | is ($b, 4); |
34 | is ($@, ""); |
35 | 5; |
36 | }; |
37 | is ($a, 5); |
38 | is ($@, ""); |
39 | |
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40 | # warn and die hooks should be disabled during constant folding |
41 | |
42 | { |
43 | my $c = 0; |
44 | local $SIG{__WARN__} = sub { $c++ }; |
45 | local $SIG{__DIE__} = sub { $c+= 2 }; |
46 | eval q{ |
47 | is($c, 0, "premature warn/die: $c"); |
48 | my $x = "a"+5; |
49 | is($c, 1, "missing warn hook"); |
50 | is($x, 5, "a+5"); |
51 | $c = 0; |
52 | $x = 1/0; |
53 | }; |
54 | like ($@, qr/division/, "eval caught division"); |
55 | is($c, 2, "missing die hook"); |
56 | } |