1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58
|
require 'strscan'
module Journey
class Scanner
def initialize
@ss = nil
end
def scan_setup str
@ss = StringScanner.new str
end
def eos?
@ss.eos?
end
def pos
@ss.pos
end
def pre_match
@ss.pre_match
end
def next_token
return if @ss.eos?
until token = scan || @ss.eos?; end
token
end
private
def scan
case
# /
when text = @ss.scan(/\//)
[:SLASH, text]
when text = @ss.scan(/\*/)
[:STAR, text]
when text = @ss.scan(/\(/)
[:LPAREN, text]
when text = @ss.scan(/\)/)
[:RPAREN, text]
when text = @ss.scan(/\|/)
[:OR, text]
when text = @ss.scan(/\./)
[:DOT, text]
when text = @ss.scan(/:\w+/)
[:SYMBOL, text]
when text = @ss.scan(/[\w%\-~]+/)
[:LITERAL, text]
# any char
when text = @ss.scan(/./)
[:LITERAL, text]
end
end
end
end
|