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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
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