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quotewords.al
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1997-03-29
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# NOTE: Derived from lib/Text/ParseWords.pm. Changes made here will be lost.
package Text::ParseWords;
sub quotewords {
# "ewords() works by simply jamming all of @lines into a single
# string in $_ and then pulling off words a bit at a time until $_
# is exhausted.
#
# The inner "for" loop builds up each word (or $field) one $snippet
# at a time. A $snippet is a quoted string, a backslashed character,
# or an unquoted string. We fall out of the "for" loop when we reach
# the end of $_ or when we hit a delimiter. Falling out of the "for"
# loop, we push the $field we've been building up onto the list of
# @words we'll be returning, and then loop back and pull another word
# off of $_.
#
# The first two cases inside the "for" loop deal with quoted strings.
# The first case matches a double quoted string, removes it from $_,
# and assigns the double quoted string to $snippet in the body of the
# conditional. The second case handles single quoted strings. In
# the third case we've found a quote at the current beginning of $_,
# but it didn't match the quoted string regexps in the first two cases,
# so it must be an unbalanced quote and we croak with an error (which can
# be caught by eval()).
#
# The next case handles backslashed characters, and the next case is the
# exit case on reaching the end of the string or finding a delimiter.
#
# Otherwise, we've found an unquoted thing and we pull of characters one
# at a time until we reach something that could start another $snippet--
# a quote of some sort, a backslash, or the delimiter. This one character
# at a time behavior was necessary if the delimiter was going to be a
# regexp (love to hear it if you can figure out a better way).
local($delim, $keep, @lines) = @_;
local(@words,$snippet,$field,$_);
$_ = join('', @lines);
while ($_) {
$field = '';
for (;;) {
$snippet = '';
if (s/^"(([^"\\]|\\[\\"])*)"//) {
$snippet = $1;
$snippet = "\"$snippet\"" if ($keep);
}
elsif (s/^'(([^'\\]|\\[\\'])*)'//) {
$snippet = $1;
$snippet = "'$snippet'" if ($keep);
}
elsif (/^["']/) {
croak "Unmatched quote";
}
elsif (s/^\\(.)//) {
$snippet = $1;
$snippet = "\\$snippet" if ($keep);
}
elsif (!$_ || s/^$delim//) {
last;
}
else {
while ($_ && !(/^$delim/ || /^['"\\]/)) {
$snippet .= substr($_, 0, 1);
substr($_, 0, 1) = '';
}
}
$field .= $snippet;
}
push(@words, $field);
}
@words;
}
1;