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1 | package Fatal; |
2 | ||
3b825e41 | 3 | use 5.006_001; |
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4 | use Carp; |
5 | use strict; | |
17f410f9 | 6 | our($AUTOLOAD, $Debug, $VERSION); |
e92e55da | 7 | |
b0cb64b6 | 8 | $VERSION = 1.03; |
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9 | |
10 | $Debug = 0 unless defined $Debug; | |
11 | ||
12 | sub import { | |
13 | my $self = shift(@_); | |
14 | my($sym, $pkg); | |
91c7a880 | 15 | my $void = 0; |
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16 | $pkg = (caller)[0]; |
17 | foreach $sym (@_) { | |
91c7a880 GS |
18 | if ($sym eq ":void") { |
19 | $void = 1; | |
20 | } | |
21 | else { | |
22 | &_make_fatal($sym, $pkg, $void); | |
23 | } | |
e92e55da MB |
24 | } |
25 | }; | |
26 | ||
27 | sub AUTOLOAD { | |
28 | my $cmd = $AUTOLOAD; | |
29 | $cmd =~ s/.*:://; | |
30 | &_make_fatal($cmd, (caller)[0]); | |
31 | goto &$AUTOLOAD; | |
32 | } | |
33 | ||
34 | sub fill_protos { | |
35 | my $proto = shift; | |
36 | my ($n, $isref, @out, @out1, $seen_semi) = -1; | |
37 | while ($proto =~ /\S/) { | |
38 | $n++; | |
39 | push(@out1,[$n,@out]) if $seen_semi; | |
40 | push(@out, $1 . "{\$_[$n]}"), next if $proto =~ s/^\s*\\([\@%\$\&])//; | |
41 | push(@out, "\$_[$n]"), next if $proto =~ s/^\s*([*\$&])//; | |
42 | push(@out, "\@_[$n..\$#_]"), last if $proto =~ s/^\s*(;\s*)?\@//; | |
43 | $seen_semi = 1, $n--, next if $proto =~ s/^\s*;//; # XXXX ???? | |
44 | die "Unknown prototype letters: \"$proto\""; | |
45 | } | |
46 | push(@out1,[$n+1,@out]); | |
47 | @out1; | |
48 | } | |
49 | ||
50 | sub write_invocation { | |
91c7a880 | 51 | my ($core, $call, $name, $void, @argvs) = @_; |
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52 | if (@argvs == 1) { # No optional arguments |
53 | my @argv = @{$argvs[0]}; | |
54 | shift @argv; | |
91c7a880 | 55 | return "\t" . one_invocation($core, $call, $name, $void, @argv) . ";\n"; |
e92e55da MB |
56 | } else { |
57 | my $else = "\t"; | |
58 | my (@out, @argv, $n); | |
59 | while (@argvs) { | |
60 | @argv = @{shift @argvs}; | |
61 | $n = shift @argv; | |
62 | push @out, "$ {else}if (\@_ == $n) {\n"; | |
63 | $else = "\t} els"; | |
64 | push @out, | |
91c7a880 | 65 | "\t\treturn " . one_invocation($core, $call, $name, $void, @argv) . ";\n"; |
e92e55da MB |
66 | } |
67 | push @out, <<EOC; | |
68 | } | |
69 | die "$name(\@_): Do not expect to get ", scalar \@_, " arguments"; | |
70 | EOC | |
71 | return join '', @out; | |
72 | } | |
73 | } | |
74 | ||
75 | sub one_invocation { | |
91c7a880 | 76 | my ($core, $call, $name, $void, @argv) = @_; |
e92e55da | 77 | local $" = ', '; |
91c7a880 GS |
78 | if ($void) { |
79 | return qq/(defined wantarray)?$call(@argv): | |
80 | $call(@argv) || croak "Can't $name(\@_)/ . | |
81 | ($core ? ': $!' : ', \$! is \"$!\"') . '"' | |
82 | } else { | |
83 | return qq{$call(@argv) || croak "Can't $name(\@_)} . | |
84 | ($core ? ': $!' : ', \$! is \"$!\"') . '"'; | |
85 | } | |
e92e55da MB |
86 | } |
87 | ||
88 | sub _make_fatal { | |
91c7a880 | 89 | my($sub, $pkg, $void) = @_; |
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90 | my($name, $code, $sref, $real_proto, $proto, $core, $call); |
91 | my $ini = $sub; | |
92 | ||
93 | $sub = "${pkg}::$sub" unless $sub =~ /::/; | |
94 | $name = $sub; | |
95 | $name =~ s/.*::// or $name =~ s/^&//; | |
91c7a880 | 96 | print "# _make_fatal: sub=$sub pkg=$pkg name=$name void=$void\n" if $Debug; |
e92e55da MB |
97 | croak "Bad subroutine name for Fatal: $name" unless $name =~ /^\w+$/; |
98 | if (defined(&$sub)) { # user subroutine | |
99 | $sref = \&$sub; | |
100 | $proto = prototype $sref; | |
101 | $call = '&$sref'; | |
102 | } elsif ($sub eq $ini) { # Stray user subroutine | |
103 | die "$sub is not a Perl subroutine" | |
104 | } else { # CORE subroutine | |
105 | $proto = eval { prototype "CORE::$name" }; | |
106 | die "$name is neither a builtin, nor a Perl subroutine" | |
107 | if $@; | |
108 | die "Cannot make a non-overridable builtin fatal" | |
109 | if not defined $proto; | |
110 | $core = 1; | |
111 | $call = "CORE::$name"; | |
112 | } | |
113 | if (defined $proto) { | |
114 | $real_proto = " ($proto)"; | |
115 | } else { | |
116 | $real_proto = ''; | |
117 | $proto = '@'; | |
118 | } | |
119 | $code = <<EOS; | |
120 | sub$real_proto { | |
121 | local(\$", \$!) = (', ', 0); | |
122 | EOS | |
123 | my @protos = fill_protos($proto); | |
91c7a880 | 124 | $code .= write_invocation($core, $call, $name, $void, @protos); |
e92e55da MB |
125 | $code .= "}\n"; |
126 | print $code if $Debug; | |
2ba6ecf4 GS |
127 | { |
128 | no strict 'refs'; # to avoid: Can't use string (...) as a symbol ref ... | |
129 | $code = eval("package $pkg; use Carp; $code"); | |
130 | die if $@; | |
db376a24 | 131 | no warnings; # to avoid: Subroutine foo redefined ... |
2ba6ecf4 GS |
132 | *{$sub} = $code; |
133 | } | |
e92e55da MB |
134 | } |
135 | ||
136 | 1; | |
137 | ||
138 | __END__ | |
139 | ||
140 | =head1 NAME | |
141 | ||
142 | Fatal - replace functions with equivalents which succeed or die | |
143 | ||
144 | =head1 SYNOPSIS | |
145 | ||
146 | use Fatal qw(open close); | |
147 | ||
148 | sub juggle { . . . } | |
149 | import Fatal 'juggle'; | |
150 | ||
151 | =head1 DESCRIPTION | |
152 | ||
153 | C<Fatal> provides a way to conveniently replace functions which normally | |
59d9ee20 | 154 | return a false value when they fail with equivalents which raise exceptions |
e92e55da | 155 | if they are not successful. This lets you use these functions without |
59d9ee20 GS |
156 | having to test their return values explicitly on each call. Exceptions |
157 | can be caught using C<eval{}>. See L<perlfunc> and L<perlvar> for details. | |
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158 | |
159 | The do-or-die equivalents are set up simply by calling Fatal's | |
160 | C<import> routine, passing it the names of the functions to be | |
161 | replaced. You may wrap both user-defined functions and overridable | |
162 | CORE operators (except C<exec>, C<system> which cannot be expressed | |
163 | via prototypes) in this way. | |
164 | ||
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165 | If the symbol C<:void> appears in the import list, then functions |
166 | named later in that import list raise an exception only when | |
167 | these are called in void context--that is, when their return | |
168 | values are ignored. For example | |
169 | ||
170 | use Fatal qw/:void open close/; | |
171 | ||
172 | # properly checked, so no exception raised on error | |
173 | if(open(FH, "< /bogotic") { | |
174 | warn "bogo file, dude: $!"; | |
175 | } | |
176 | ||
177 | # not checked, so error raises an exception | |
178 | close FH; | |
179 | ||
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180 | =head1 AUTHOR |
181 | ||
182 | Lionel.Cons@cern.ch | |
183 | ||
184 | prototype updates by Ilya Zakharevich ilya@math.ohio-state.edu | |
185 | ||
186 | =cut |