instiki/lib/syntax/lang/yaml.rb

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2007-01-22 15:36:51 +01:00
require 'syntax'
module Syntax
# A simple implementation of an YAML lexer. It handles most cases. It is
# not a validating lexer.
class YAML < Tokenizer
# Step through a single iteration of the tokenization process. This will
# yield (potentially) many tokens, and possibly zero tokens.
def step
if bol?
case
when scan(/---(\s*.+)?$/)
start_group :document, matched
when scan(/(\s*)([a-zA-Z][-\w]*)(\s*):/)
start_group :normal, subgroup(1)
start_group :key, subgroup(2)
start_group :normal, subgroup(3)
start_group :punct, ":"
when scan(/(\s*)-/)
start_group :normal, subgroup(1)
start_group :punct, "-"
when scan(/\s*$/)
start_group :normal, matched
when scan(/#.*$/)
start_group :comment, matched
else
append getch
end
else
case
when scan(/[\n\r]+/)
start_group :normal, matched
when scan(/[ \t]+/)
start_group :normal, matched
when scan(/!+(.*?^)?\S+/)
start_group :type, matched
when scan(/&\S+/)
start_group :anchor, matched
when scan(/\*\S+/)
start_group :ref, matched
when scan(/\d\d:\d\d:\d\d/)
start_group :time, matched
when scan(/\d\d\d\d-\d\d-\d\d\s\d\d:\d\d:\d\d(\.\d+)? [-+]\d\d:\d\d/)
start_group :date, matched
when scan(/['"]/)
start_group :punct, matched
scan_string matched
when scan(/:\w+/)
start_group :symbol, matched
when scan(/[:]/)
start_group :punct, matched
when scan(/#.*$/)
start_group :comment, matched
when scan(/>-?/)
start_group :punct, matched
start_group :normal, scan(/.*$/)
append getch until eos? || bol?
return if eos?
indent = check(/ */)
start_group :string
loop do
line = check_until(/[\n\r]|\Z/)
break if line.nil?
if line.chomp.length > 0
this_indent = line.chomp.match( /^\s*/ )[0]
break if this_indent.length < indent.length
end
append scan_until(/[\n\r]|\Z/)
end
else
start_group :normal, scan_until(/(?=$|#)/)
end
end
end
private
def scan_string( delim )
regex = /(?=[#{delim=="'" ? "" : "\\\\"}#{delim}])/
loop do
text = scan_until( regex )
if text.nil?
start_group :string, scan_until( /\Z/ )
break
else
start_group :string, text unless text.empty?
end
case peek(1)
when "\\"
start_group :expr, scan(/../)
else
start_group :punct, getch
break
end
end
end
end
SYNTAX["yaml"] = YAML
end