Ruby/Racc: パースに失敗した位置（行、桁）を得る - Qiita

# parser.y class Parser rule program: "a" "b" "c" "d" ";" { puts "program found" result = val } end ---- header TokenValue = Struct.new(:value, :pos) ---- inner def initialize(src, tokens) @src = src @tokens = tokens end def next_token @tokens.shift end def parse do_parse end def get_lineno_and_range(pos) lineno = 1 line_start = 0 range = nil @src.each_line do |line| next_line_start = line_start +