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-rw-r--r--lib/irb/slex.rb279
1 files changed, 279 insertions, 0 deletions
diff --git a/lib/irb/slex.rb b/lib/irb/slex.rb
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+++ b/lib/irb/slex.rb
@@ -0,0 +1,279 @@
+#
+# irb-slex.rb - symple lex analizer
+# $Release Version: 0.6$
+# $Revision$
+# $Date$
+# by Keiju ISHITSUKA(Nippon Rational Inc.)
+#
+# --
+#
+#
+#
+
+require "e2mmap"
+
+class SLex
+ @RCS_ID='-$Id$-'
+
+ extend Exception2MessageMapper
+ def_exception :ErrNodeNothing, "node nothing"
+ def_exception :ErrNodeAlreadyExists, "node already exists"
+
+ class << self
+ attr :debug_level, TRUE
+ def debug?
+ debug_level > 0
+ end
+ end
+ @debug_level = 0
+
+ def initialize
+ @head = Node.new("")
+ end
+
+ def def_rule(token, preproc = nil, postproc = nil)
+ # print node.inspect, "\n" if SLex.debug?
+ postproc = proc if iterator?
+ node = create(token, preproc, postproc)
+ end
+
+ def def_rules(*tokens)
+ if iterator?
+ p = proc
+ end
+ for token in tokens
+ def_rule(token, nil, p)
+ end
+ end
+
+ def preporc(token, proc)
+ node = search(token)
+ node.preproc=proc
+ end
+
+ def postproc(token)
+ node = search(token, proc)
+ node.postproc=proc
+ end
+
+ def search(token)
+ @head.search(token.split(//))
+ end
+
+ def create(token, preproc = nil, postproc = nil)
+ @head.create_subnode(token.split(//), preproc, postproc)
+ end
+
+ def match(token)
+ case token
+ when Array
+ when String
+ token = token.split(//)
+ match(token.split(//))
+ else
+ return @head.match_io(token)
+ end
+ ret = @head.match(token)
+ printf "match end: %s:%s", ret, token.inspect if SLex.debug?
+ ret
+ end
+
+ def inspect
+ format("<SLex: @head = %s>", @head.inspect)
+ end
+
+ #----------------------------------------------------------------------
+ #
+ # class Node -
+ #
+ #----------------------------------------------------------------------
+ class Node
+ # if postproc no exist, this node is abstract node.
+ # if postproc isn't nil, this node is real node.
+ def initialize(preproc = nil, postproc = nil)
+ @Tree = {}
+ @preproc = preproc
+ @postproc = postproc
+ end
+
+ attr :preproc, TRUE
+ attr :postproc, TRUE
+
+ def search(chrs, opt = nil)
+ return self if chrs.empty?
+ ch = chrs.shift
+ if node = @Tree[ch]
+ node.search(chrs, opt)
+ else
+ if opt
+ chrs.unshift ch
+ self.create_subnode(chrs)
+ else
+ SLex.fail ErrNodeNothing
+ end
+ end
+ end
+
+ def create_subnode(chrs, preproc = nil, postproc = nil)
+ if chrs.empty?
+ if @postproc
+ p node
+ SLex.fail ErrNodeAlreadyExists
+ else
+ print "Warn: change abstruct node to real node\n" if SLex.debug?
+ @preproc = preproc
+ @postproc = postproc
+ end
+ return self
+ end
+
+ ch = chrs.shift
+ if node = @Tree[ch]
+ if chrs.empty?
+ if node.postproc
+ p node
+ p self
+ p ch
+ p chrs
+ SLex.fail ErrNodeAlreadyExists
+ else
+ print "Warn: change abstruct node to real node\n" if SLex.debug?
+ node.preproc = preproc
+ node.postproc = postproc
+ end
+ else
+ node.create_subnode(chrs, preproc, postproc)
+ end
+ else
+ if chrs.empty?
+ node = Node.new(preproc, postproc)
+ else
+ node = Node.new
+ node.create_subnode(chrs, preproc, postproc)
+ end
+ @Tree[ch] = node
+ end
+ node
+ end
+
+ #
+ # chrs: String
+ # character array
+ # io It must have getc()/ungetc(), and ungetc() can be
+ # called any number of times.
+ #
+ def match(chrs, op = "")
+ print "match>: ", chrs, "op:", op, "\n" if SLex.debug?
+ if chrs.empty?
+ if @preproc.nil? || @preproc.call(op, chrs)
+ printf "op1: %s\n", op if SLex.debug?
+ @postproc.call(op, chrs)
+ else
+ nil
+ end
+ else
+ ch = chrs.shift
+ if node = @Tree[ch]
+ if ret = node.match(chrs, op+ch)
+ return ret
+ else
+ chrs.unshift ch
+ if @postproc and @preproc.nil? || @preproc.call(op, chrs)
+ printf "op2: %s\n", op.inspect if SLex.debug?
+ ret = @postproc.call(op, chrs)
+ return ret
+ else
+ return nil
+ end
+ end
+ else
+ chrs.unshift ch
+ if @postproc and @preproc.nil? || @preproc.call(op, chrs)
+ printf "op3: %s\n", op if SLex.debug?
+ @postproc.call(op, chrs)
+ return ""
+ else
+ return nil
+ end
+ end
+ end
+ end
+
+ def match_io(io, op = "")
+ if op == ""
+ ch = io.getc
+ if ch == nil
+ return nil
+ end
+ else
+ ch = io.getc_of_rests
+ end
+ if ch.nil?
+ if @preproc.nil? || @preproc.call(op, io)
+ printf "op1: %s\n", op if SLex.debug?
+ @postproc.call(op, io)
+ else
+ nil
+ end
+ else
+ if node = @Tree[ch]
+ if ret = node.match_io(io, op+ch)
+ ret
+ else
+ io.ungetc ch
+ if @postproc and @preproc.nil? || @preproc.call(op, io)
+ printf "op2: %s\n", op.inspect if SLex.debug?
+ @postproc.call(op, io)
+ else
+ nil
+ end
+ end
+ else
+ io.ungetc ch
+ if @postproc and @preproc.nil? || @preproc.call(op, io)
+ printf "op3: %s\n", op if SLex.debug?
+ @postproc.call(op, io)
+ else
+ nil
+ end
+ end
+ end
+ end
+ end
+end
+
+if $0 == __FILE__
+ # Tracer.on
+ case $1
+ when "1"
+ tr = SLex.new
+ print "0: ", tr.inspect, "\n"
+ tr.def_rule("=") {print "=\n"}
+ print "1: ", tr.inspect, "\n"
+ tr.def_rule("==") {print "==\n"}
+ print "2: ", tr.inspect, "\n"
+
+ print "case 1:\n"
+ print tr.match("="), "\n"
+ print "case 2:\n"
+ print tr.match("=="), "\n"
+ print "case 3:\n"
+ print tr.match("=>"), "\n"
+
+ when "2"
+ tr = SLex.new
+ print "0: ", tr.inspect, "\n"
+ tr.def_rule("=") {print "=\n"}
+ print "1: ", tr.inspect, "\n"
+ tr.def_rule("==", proc{FALSE}) {print "==\n"}
+ print "2: ", tr.inspect, "\n"
+
+ print "case 1:\n"
+ print tr.match("="), "\n"
+ print "case 2:\n"
+ print tr.match("=="), "\n"
+ print "case 3:\n"
+ print tr.match("=>"), "\n"
+ end
+ exit
+end