1Long::Jump(3) User Contributed Perl Documentation Long::Jump(3)
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6 Long::Jump - Mechanism for returning to a specific point from a deeply
7 nested stack.
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10 This module essentially provides a multi-level return. You can mark a
11 spot with "setjump()" and then unwind the stack back to that point from
12 any nested stack frame by name using "longjump()". You can also provide
13 a list of return values.
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15 This is not quite a match for C's long jump, but it is "close enough".
16 It is safer than C's jump in that it only lets you escape frames by
17 going up the stack, you cannot jump in other ways.
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20 use Long::Jump qw/setjump longjump/;
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22 my $out = setjump foo => sub {
23 bar();
24 ...; # Will never get here
25 };
26 is($out, [qw/x y z/], "Got results of the long jump");
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28 $out = setjump foo => sub {
29 print "Not calling longjump";
30 };
31 is($out, undef, "longjump was not called so we got an undef response");
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33 sub bar {
34 baz();
35 return 'bar'; # Will never get here
36 }
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38 sub baz {
39 bat();
40 return 'baz'; # Will never get here
41 }
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43 sub bat {
44 my @out = qw/x y z/;
45 longjump foo => @out;
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47 return 'bat'; # Will never get here
48 }
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51 $out = setjump($NAME, sub { ... })
52 $out = setjump $NAME, sub { ... }
53 $out = setjump($NAME => sub { ... })
54 $out = setjump $NAME => sub { ... }
55 Set a named point to which you will return when calling
56 "longjump()". $out will be "undef" if "longjump()" was not called.
57 $out will be an arrayref if "longjump()" was called. The $out
58 arrayref will be empty, but present if "longjump()" is called
59 without any return values.
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61 The return value will always be false if "longjump" was not called,
62 and will always be true if it was called.
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64 You cannot nest multiple jump points with the same name, but you
65 can nest multiple jump points if they have unqiue names.
66 "longjump()" will always jump to the correct name.
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68 longjump($NAME)
69 longjump $NAME
70 longjump($NAME, @RETURN_LIST)
71 longjump($NAME => @RETURN_LIST)
72 longjump $NAME => @RETURN_LIST
73 Jump to the named point, optionally with values to return. This
74 will throw exceptions if you use an invalid $NAME, which includes
75 the case of calling it without a set jump point.
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78 The source code repository for Long-Jump can be found at
79 https://github.com/exodist/Long-Jump/.
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82 Chad Granum <exodist@cpan.org>
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85 Chad Granum <exodist@cpan.org>
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88 Copyright 2018 Chad Granum <exodist7@gmail.com>.
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90 This program is free software; you can redistribute it and/or modify it
91 under the same terms as Perl itself.
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93 See http://dev.perl.org/licenses/
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97perl v5.34.0 2021-07-22 Long::Jump(3)