| 1 | =head1 NAME |
1 | =head1 NAME |
| 2 | |
2 | |
| 3 | Coro - create and manage coroutines |
3 | Coro - create and manage simple coroutines |
| 4 | |
4 | |
| 5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
| 6 | |
6 | |
| 7 | use Coro; |
7 | use Coro; |
| 8 | |
8 | |
| 9 | $new = new Coro sub { |
9 | $new = new Coro sub { |
| 10 | print "in coroutine, switching back\n"; |
10 | print "in coroutine, switching back\n"; |
| 11 | $Coro::main->resume; |
11 | $new->transfer($main); |
| 12 | print "in coroutine again, switching back\n"; |
12 | print "in coroutine again, switching back\n"; |
| 13 | $Coro::main->resume; |
13 | $new->transfer($main); |
| 14 | }; |
14 | }; |
| 15 | |
15 | |
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16 | $main = new Coro; |
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17 | |
| 16 | print "in main, switching to coroutine\n"; |
18 | print "in main, switching to coroutine\n"; |
| 17 | $new->resume; |
19 | $main->transfer($new); |
| 18 | print "back in main, switch to coroutine again\n"; |
20 | print "back in main, switch to coroutine again\n"; |
| 19 | $new->resume; |
21 | $main->transfer($new); |
| 20 | print "back in main\n"; |
22 | print "back in main\n"; |
| 21 | |
23 | |
| 22 | =head1 DESCRIPTION |
24 | =head1 DESCRIPTION |
| 23 | |
25 | |
| 24 | This module implements coroutines. Coroutines, similar to continuations, |
26 | This module implements coroutines. Coroutines, similar to continuations, |
| … | |
… | |
| 41 | |
43 | |
| 42 | require XSLoader; |
44 | require XSLoader; |
| 43 | XSLoader::load Coro, $VERSION; |
45 | XSLoader::load Coro, $VERSION; |
| 44 | } |
46 | } |
| 45 | |
47 | |
| 46 | =item $main |
48 | =item $coro = new [$coderef [, @args]] |
| 47 | |
49 | |
| 48 | This coroutine represents the main program. |
50 | Create a new coroutine and return it. The first C<transfer> call to this |
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51 | coroutine will start execution at the given coderef. If, the subroutine |
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52 | returns it will be executed again. |
| 49 | |
53 | |
| 50 | =item $current |
54 | If the coderef is omitted this function will create a new "empty" |
| 51 | |
55 | coroutine, i.e. a coroutine that cannot be transfered to but can be used |
| 52 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
56 | to save the current coroutine in. |
| 53 | |
57 | |
| 54 | =cut |
58 | =cut |
| 55 | |
59 | |
| 56 | $main = $current = _newprocess { |
60 | sub new { |
| 57 | # never being called |
61 | my $class = $_[0]; |
| 58 | }; |
62 | my $proc = $_[1] || sub { die "tried to transfer to an empty coroutine" }; |
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63 | bless _newprocess { |
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64 | do { |
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65 | eval { &$proc }; |
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66 | if ($@) { |
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67 | $error_msg = $@; |
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68 | $error_coro = _newprocess { }; |
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69 | &transfer($error_coro, $error); |
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70 | } |
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71 | } while (1); |
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72 | }, $class; |
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73 | } |
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74 | |
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75 | =item $prev->transfer($next) |
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76 | |
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77 | Save the state of the current subroutine in $prev and switch to the |
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78 | coroutine saved in $next. |
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79 | |
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80 | =cut |
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81 | |
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82 | # I call the _transfer function from a perl function |
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83 | # because that way perl saves all important things on |
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84 | # the stack. |
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85 | sub transfer { |
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86 | _transfer($_[0], $_[1]); |
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87 | } |
| 59 | |
88 | |
| 60 | =item $error, $error_msg, $error_coro |
89 | =item $error, $error_msg, $error_coro |
| 61 | |
90 | |
| 62 | This coroutine will be called on fatal errors. C<$error_msg> and |
91 | This coroutine will be called on fatal errors. C<$error_msg> and |
| 63 | C<$error_coro> return the error message and the error-causing coroutine, |
92 | C<$error_coro> return the error message and the error-causing coroutine |
| 64 | respectively. |
93 | (NOT an object) respectively. This API might change. |
| 65 | |
94 | |
| 66 | =cut |
95 | =cut |
| 67 | |
96 | |
| 68 | $error_msg = |
97 | $error_msg = |
| 69 | $error_coro = undef; |
98 | $error_coro = undef; |
| 70 | |
99 | |
| 71 | $error = _newprocess { |
100 | $error = _newprocess { |
| 72 | print STDERR "FATAL: $error_msg\nprogram aborted\n"; |
101 | print STDERR "FATAL: $error_msg\nprogram aborted\n"; |
| 73 | exit 250; |
102 | exit 50; |
| 74 | }; |
103 | }; |
| 75 | |
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| 76 | =item $coro = new $coderef [, @args] |
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| 77 | |
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| 78 | Create a new coroutine and return it. The first C<resume> call to this |
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| 79 | coroutine will start execution at the given coderef. If it returns it |
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| 80 | should return a coroutine to switch to. If, after returning, the coroutine |
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| 81 | is C<resume>d again it starts execution again at the givne coderef. |
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| 82 | |
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| 83 | =cut |
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| 84 | |
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| 85 | sub new { |
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| 86 | my $class = $_[0]; |
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| 87 | my $proc = $_[1]; |
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| 88 | bless _newprocess { |
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| 89 | do { |
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| 90 | eval { &$proc->resume }; |
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| 91 | if ($@) { |
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| 92 | ($error_msg, $error_coro) = ($@, $current); |
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| 93 | $error->resume; |
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| 94 | } |
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| 95 | } while (1); |
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| 96 | }, $class; |
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| 97 | } |
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| 98 | |
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| 99 | =item $coro->resume |
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| 100 | |
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| 101 | Resume execution at the given coroutine. |
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| 102 | |
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| 103 | =cut |
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| 104 | |
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| 105 | my $prev; |
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| 106 | |
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| 107 | # I call the _transfer function from a pelr function |
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| 108 | # because that way perl saves all important things on |
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| 109 | # the stack. |
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| 110 | sub resume { |
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| 111 | $prev = $current; $current = $_[0]; |
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| 112 | _transfer($prev, $current); |
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| 113 | } |
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| 114 | |
104 | |
| 115 | 1; |
105 | 1; |
| 116 | |
106 | |
| 117 | =back |
107 | =back |
| 118 | |
108 | |
