nbc added

1 files changed, 26 insertions, 0 deletions

diff --git a/src/nbc/substitution.sml b/src/nbc/substitution.sml
new file mode 100644
index 0000000..57d55cf
--- /dev/null
+++ b/src/nbc/substitution.sml
@@ -0,0 +1,26 @@
+signature SUBSTITUTION = sig
+	val substitute: (string -> string) -> string -> string option
+end
+
+structure Substitution :> SUBSTITUTION = struct
+	structure LrVals = SubstitutionGrmLrValsFun (structure Token = LrParser.Token)
+	structure Lex = SubstitutionLexFun (structure Tokens = LrVals.Tokens)
+	structure Parser = JoinWithArg (
+		structure ParserData = LrVals.ParserData
+		structure Lex = Lex
+		structure LrParser = LrParser
+	)
+	fun substitute lookup source =
+		let
+			val position = ref 0
+			val instream = TextIO.openString source
+			fun read n = TextIO.inputN (instream, n)
+			val lexer = Parser.makeLexer read (ref 0)
+			fun error (_, _, _) = ()
+			val (result, _) = Parser.parse (0, lexer, error, lookup)
+			val () = TextIO.closeIn instream
+		in
+			SOME result
+		end
+		handle Parser.ParseError => NONE
+end