StreamParser
StreamParser is a Ruby Module to help build fast and efficent parsers.
Installation
Add gem 'stream_parser' to your Gemfile or install via RubyGems (gem install stream_parser)
Usage Example:
Below is an example to extract all quoted strings from a string:
class QuotedStringFinder
include StreamParser
def parse
@stack = []
@results = []
while !eos?
case @stack.last
when :double_quoted_string
if scan_until('"') # Can only use pre_match is there is a match
@results << pre_match
@stack.pop
end
when :single_quoted_string
if scan_until("'") # Can only use pre_match is there is a match
@results << pre_match
@stack.pop
end
else
scan_until(/['"]/)
if match == '"'
@stack << :double_quoted_string
elsif match == "'"
@stack << :single_quoted_string
end
end
end
raise SyntaxError.new("Unbalanced Quotes in string") if !@stack.empty?
@results
end
end
QuotedStringFinder.parse(%q{Here "are" a few 'examples' for "you"})
# => ["are", "examples", "you"]
QuotedStringFinder.parse(%q{Here "ar})
# => SyntaxError "Unbalanced Quotes in string"Although we grab quoted values ourselfs in this example there is a quoted_value helper as well as a
StreamParser::HTML which provides additional helpers such as next_tag, scan_for_tag, next_end_tag and others.