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0111154e Z |
1 | warn "Legacy library @{[(caller(0))[6]]} will be removed from the Perl core distribution in the next major release. Please install it from the CPAN distribution Perl4::CoreLibs. It is being used at @{[(caller)[1]]}, line @{[(caller)[2]]}.\n"; |
2 | ||
99b89507 LW |
3 | # exceptions.pl |
4 | # tchrist@convex.com | |
a6d71656 GS |
5 | # |
6 | # This library is no longer being maintained, and is included for backward | |
7 | # compatibility with Perl 4 programs which may require it. | |
25209816 S |
8 | # This legacy library is deprecated and will be removed in a future |
9 | # release of perl. | |
a6d71656 GS |
10 | # |
11 | # In particular, this should not be used as an example of modern Perl | |
12 | # programming techniques. | |
25209816 | 13 | |
99b89507 LW |
14 | # Here's a little code I use for exception handling. It's really just |
15 | # glorfied eval/die. The way to use use it is when you might otherwise | |
16 | # exit, use &throw to raise an exception. The first enclosing &catch | |
17 | # handler looks at the exception and decides whether it can catch this kind | |
18 | # (catch takes a list of regexps to catch), and if so, it returns the one it | |
19 | # caught. If it *can't* catch it, then it will reraise the exception | |
20 | # for someone else to possibly see, or to die otherwise. | |
21 | # | |
22 | # I use oddly named variables in order to make darn sure I don't conflict | |
23 | # with my caller. I also hide in my own package, and eval the code in his. | |
24 | # | |
25 | # The EXCEPTION: prefix is so you can tell whether it's a user-raised | |
26 | # exception or a perl-raised one (eval error). | |
27 | # | |
28 | # --tom | |
29 | # | |
30 | # examples: | |
31 | # if (&catch('/$user_input/', 'regexp', 'syntax error') { | |
32 | # warn "oops try again"; | |
33 | # redo; | |
34 | # } | |
35 | # | |
36 | # if ($error = &catch('&subroutine()')) { # catches anything | |
37 | # | |
38 | # &throw('bad input') if /^$/; | |
39 | ||
40 | sub catch { | |
41 | package exception; | |
42 | local($__code__, @__exceptions__) = @_; | |
43 | local($__package__) = caller; | |
44 | local($__exception__); | |
45 | ||
46 | eval "package $__package__; $__code__"; | |
47 | if ($__exception__ = &'thrown) { | |
48 | for (@__exceptions__) { | |
49 | return $__exception__ if /$__exception__/; | |
50 | } | |
51 | &'throw($__exception__); | |
52 | } | |
53 | } | |
54 | ||
55 | sub throw { | |
56 | local($exception) = @_; | |
57 | die "EXCEPTION: $exception\n"; | |
58 | } | |
59 | ||
60 | sub thrown { | |
61 | $@ =~ /^(EXCEPTION: )+(.+)/ && $2; | |
62 | } | |
63 | ||
64 | 1; |