source: perl/lib/BarnOwl/Completion/Context.pm @ e97c5d05

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Last change on this file since e97c5d05 was e97c5d05, checked in by David Benjamin <davidben@mit.edu>, 12 years ago
Implement a shift_words method on completion contexts. This allows completion methods to easily pass on the remainder of a command-line to another completer if appropriate.
  • Property mode set to 100644
File size: 4.0 KB
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1use warnings;
2use strict;
3
4=head1 NAME
5
6BarnOwl::Completion::Context
7
8=head1 DESCRIPTION
9
10BarnOwl::Completion::Context is the context that is passed to a
11completion function by BarnOwl. It contains information on the text
12being completed.
13
14=head1 METHODS
15
16=head2 line
17
18The entire command-line currently being completed.
19
20=head2 point
21
22The index of the cursor in C<line>, in the range C<[0,len($line)]>.
23
24=head2 words
25
26The current command-line, tokenized according to BarnOwl's
27tokenization rules, as an array reference.
28
29=head2 word
30
31The current word the point is sitting in, as an index into C<words>.
32
33=head2 word_point
34
35The index of the point within C<$words->[$word]>.
36
37=cut
38
39package BarnOwl::Completion::Context;
40
41use base qw(Class::Accessor::Fast);
42use Carp qw(croak);
43
44__PACKAGE__->mk_ro_accessors(qw(line point words word word_point
45                                word_start word_end));
46
47sub new {
48    my $class = shift;
49    my $before_point = shift;
50    my $after_point = shift;
51
52    my $line  = $before_point . $after_point;
53    my $point = length ($before_point);
54    my ($words, $word, $word_point,
55        $word_start, $word_end) = tokenize($line, $point);
56
57    my $self = {
58        line  => $line,
59        point => $point,
60        words => $words,
61        word  => $word,
62        word_point => $word_point,
63        word_start => $word_start,
64        word_end   => $word_end
65       };
66    return bless($self, $class);
67}
68
69=head2 shift_words N
70
71Returns a new C<Context> object, with the leading C<N> words
72stripped. All fields are updated as appopriate. If C<N> > C<<
73$self->word >>, C<croak>s with an error message.
74
75=cut
76
77sub shift_words {
78    my $self = shift;
79    my $n    = shift;
80
81    if($n > $self->word) {
82        croak "Context::shift: Unable to shift $n words";
83    }
84
85    my $before = substr($self->line, 0, $self->point);
86    my $after  = substr($self->line, $self->point);
87
88    return BarnOwl::Completion::Context->new(BarnOwl::skiptokens($before, $n),
89                                             $after);
90}
91
92=for doc
93
94Ideally, this should use the same codepath we use to /actually/
95tokenize commands, but for now, make sure this is kept in sync with
96owl_parseline in util.c
97
98Unlike owl_parseline, we always return a result, even in the presence
99of parse errors, since we may be called on incomplete command-lines.
100
101The owl_parseline rules are:
102
103* Tokenize on ' ' and '\t'
104* ' and " are quote characters
105* \ has no effect
106
107=cut
108
109my $boring = qr{[^'" \t]};
110my $quote  = qr{['"]};
111my $space  = qr{[ \t]};
112
113sub tokenize {
114    my $line = shift;
115    my $point = shift;
116
117    my @words = ();
118    my $cword = 0;
119    my $cword_start;
120    my $cword_end;
121    my $word_point;
122
123    my $word = '';
124    my $wstart = 0;
125    my $skipped = 0;
126
127    pos($line) = 0;
128    while(pos($line) < length($line)) {
129        if($line =~ m{\G ($boring+) }gcx) {
130            $word .= $1;
131        } elsif ($line =~ m{\G ($quote)}gcx) {
132            my $chr = $1;
133            $skipped++ if pos($line) > $point;
134            if($line =~ m{\G ([^$chr]*) $chr}gcx) {
135                $word .= $1;
136                $skipped++ if pos($line) > $point;
137            } else {
138                $word .= substr($line, pos($line));
139                pos($line) = length($line);
140            }
141        }
142
143        if ($line =~ m{\G ($space+|$)}gcx) {
144            my $wend = pos($line) - length($1);
145            push @words, $word;
146            $cword++ unless $wend >= $point;
147            if(($wend >= $point) && !defined($word_point)) {
148                $word_point = length($word) - ($wend - $point) + $skipped;
149                $cword_start = $wstart;
150                $cword_end   = $wend;
151            }
152            $word = '';
153            $wstart = pos($line);
154            $skipped = 0;
155        }
156    }
157
158    if(length($word)) { die("Internal error, leftover=$word"); }
159
160    unless(defined($word_point)) {
161        $word_point = 0;
162        $cword_start = $cword_end = $point;
163        push @words, '' if $point > 0;
164    }
165
166    return (\@words, $cword, $word_point, $cword_start, $cword_end);
167}
168
1691;
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