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1 | package Function::Parameters::Info; |
2 | |
3 | use v5.14.0; |
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4 | use warnings; |
5 | |
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6 | our $VERSION = '0.04'; |
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7 | |
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8 | # If Moo isn't loaded yet but Moose is, avoid pulling in Moo and fall back to Moose |
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9 | my $Moo; |
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10 | BEGIN { |
11 | if ($INC{'Moose.pm'} && !$INC{'Moo.pm'}) { |
12 | $Moo = 'Moose'; |
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13 | } else { |
14 | require Moo; |
15 | $Moo = 'Moo'; |
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16 | } |
17 | $Moo->import; |
18 | } |
19 | |
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20 | { |
21 | package Function::Parameters::Param; |
22 | |
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23 | BEGIN { $Moo->import; } |
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24 | use overload |
25 | fallback => 1, |
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26 | '""' => sub { $_[0]->name }, |
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27 | ; |
28 | |
29 | has $_ => (is => 'ro') for qw(name type); |
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30 | |
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31 | __PACKAGE__->meta->make_immutable; |
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32 | } |
33 | |
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34 | my @pn_ro = glob '{positional,named}_{required,optional}'; |
35 | |
36 | for my $attr (qw[keyword invocant slurpy], map "_$_", @pn_ro) { |
37 | has $attr => ( |
38 | is => 'ro', |
39 | ); |
40 | } |
41 | |
42 | for my $gen (join "\n", map "sub $_ { \@{\$_[0]->_$_} }", @pn_ro) { |
43 | eval "$gen\n1" or die $@; |
44 | } |
45 | |
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46 | sub args_min { |
47 | my $self = shift; |
48 | my $r = 0; |
49 | $r++ if defined $self->invocant; |
50 | $r += $self->positional_required; |
51 | $r += $self->named_required * 2; |
52 | $r |
53 | } |
54 | |
55 | sub args_max { |
56 | my $self = shift; |
57 | return 0 + 'Inf' if defined $self->slurpy || $self->named_required || $self->named_optional; |
58 | my $r = 0; |
59 | $r++ if defined $self->invocant; |
60 | $r += $self->positional_required; |
61 | $r += $self->positional_optional; |
62 | $r |
63 | } |
64 | |
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65 | __PACKAGE__->meta->make_immutable; |
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66 | |
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67 | 'ok' |
68 | |
69 | __END__ |
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70 | |
71 | =encoding UTF-8 |
72 | |
73 | =head1 NAME |
74 | |
75 | Function::Parameters::Info - Information about parameter lists |
76 | |
77 | =head1 SYNOPSIS |
78 | |
79 | use Function::Parameters; |
80 | |
81 | fun foo($x, $y, :$hello, :$world = undef) {} |
82 | |
83 | my $info = Function::Parameters::info \&foo; |
84 | my $p0 = $info->invocant; # undef |
85 | my @p1 = $info->positional_required; # ('$x', '$y') |
86 | my @p2 = $info->positional_optional; # () |
87 | my @p3 = $info->named_required; # ('$hello') |
88 | my @p4 = $info->named_optional; # ('$world') |
89 | my $p5 = $info->slurpy; # undef |
90 | my $min = $info->args_min; # 4 |
91 | my $max = $info->args_max; # inf |
92 | |
93 | my $invocant = Function::Parameters::info(method () { 42 })->invocant; # '$self' |
94 | |
95 | my $slurpy = Function::Parameters::info(fun {})->slurpy; # '@_' |
96 | |
97 | =head1 DESCRIPTION |
98 | |
99 | L<C<Function::Parameters::info>|Function::Parameters/Introspection> returns |
100 | objects of this class to describe parameter lists of functions. The following |
101 | methods are available: |
102 | |
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103 | =head2 $info->invocant |
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104 | |
105 | Returns the name of the variable into which the first argument is |
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106 | L<C<shift>|perlfunc/shift>ed automatically, or C<undef> if no such thing |
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107 | exists. This will usually return C<'$self'> for methods. |
108 | |
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109 | =head2 $info->positional_required |
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110 | |
111 | Returns a list of the names of the required positional parameters (or a count |
112 | in scalar context). |
113 | |
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114 | =head2 $info->positional_optional |
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115 | |
116 | Returns a list of the names of the optional positional parameters (or a count |
117 | in scalar context). |
118 | |
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119 | =head2 $info->named_required |
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120 | |
121 | Returns a list of the names of the required named parameters (or a count |
122 | in scalar context). |
123 | |
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124 | =head2 $info->named_optional |
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125 | |
126 | Returns a list of the names of the optional named parameters (or a count |
127 | in scalar context). |
128 | |
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129 | =head2 $info->slurpy |
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130 | |
131 | Returns the name of the final array or hash that gobbles up all remaining |
132 | arguments, or C<undef> if no such thing exists. |
133 | |
134 | As a special case, functions defined without an explicit parameter list (i.e. |
135 | without C<( )>) will return C<'@_'> here because they accept any number of |
136 | arguments. |
137 | |
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138 | =head2 $info->args_min |
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139 | |
140 | Returns the minimum number of arguments this function requires. This is |
141 | computed as follows: Invocant and required positional parameters count 1 each. |
142 | Optional parameters don't count. Required named parameters count 2 each (key + |
143 | value). Slurpy parameters don't count either because they accept empty lists. |
144 | |
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145 | =head2 $info->args_max |
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146 | |
147 | Returns the maximum number of arguments this function accepts. This is computed |
148 | as follows: If there is any named or slurpy parameter, the result is C<Inf>. |
149 | Otherwise the result is the sum of all invocant and positional parameters. |
150 | |
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151 | =head2 Experimental feature: Types |
152 | |
153 | All the methods described above actually return parameter objects wherever the |
154 | description says "name". These objects have two methods: C<name>, which |
155 | returns the name of the parameter (as a plain string), and C<type>, which |
156 | returns the corresponding type constraint object (or undef if there was no type |
157 | specified). |
158 | |
159 | This should be invisible if you don't use types because the objects also |
160 | L<overload|overload> stringification to call C<name>. That is, if you treat |
161 | parameter objects like strings, they behave like strings (i.e. their names). |
162 | |
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163 | =head1 SEE ALSO |
164 | |
165 | L<Function::Parameters> |
166 | |
167 | =head1 AUTHOR |
168 | |
169 | Lukas Mai, C<< <l.mai at web.de> >> |
170 | |
171 | =head1 COPYRIGHT & LICENSE |
172 | |
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173 | Copyright 2013 Lukas Mai. |
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174 | |
175 | This program is free software; you can redistribute it and/or modify it |
176 | under the terms of either: the GNU General Public License as published |
177 | by the Free Software Foundation; or the Artistic License. |
178 | |
179 | See http://dev.perl.org/licenses/ for more information. |
180 | |
181 | =cut |