1 files changed, 125 insertions, 0 deletions
diff --git a/src/nbc/misc.sml b/src/nbc/misc.sml
new file mode 100644
index 0000000..4790bbc
--- /dev/null
+++ b/src/nbc/misc.sml
@@ -0,0 +1,125 @@
+signature MISC = sig
+	val inputLine: TextIO.instream -> string option
+	val sequenceFromRead: (TextIO.instream -> 'a option) -> TextIO.instream -> 'a Sequence.t
+	val sequenceLines: TextIO.instream -> string Sequence.t
+	val sortedDirectoryNoPrefix: string -> string list
+	val sortedDirectory: string -> string list
+	val substitute: (string * string) list -> string -> string option
+	val basenameWithoutExtension: string -> string
+	val split2: string -> (string * string) option
+	val longestCommonSubstring: string list -> string
+end
+
+structure Misc :> MISC = struct
+	fun |> (x, f) = f x
+	infix |>
+	fun \ f x y = f (x, y)
+	fun sequenceFromRead f ioc = Sequence.from (fn () => f ioc)
+	fun inputLine instream = case TextIO.inputLine instream of
+		NONE => NONE
+		| SOME x => SOME (String.substring (x, 0, size x - 1))
+	val sequenceLines = sequenceFromRead inputLine
+	fun sortedDirectoryNoPrefix d =
+		let
+			val h = OS.FileSys.openDir d
+			fun loop l =
+				case OS.FileSys.readDir h of
+					NONE => (
+						OS.FileSys.closeDir h
+						; ListMergeSort.sort (op >) l
+					) | SOME n => loop (
+						if String.sub (n, 0) = #"." then l
+						else n :: l
+					)
+		in
+			loop nil
+		end
+	fun sortedDirectory d =
+		map (\OS.Path.concat d) (sortedDirectoryNoPrefix d)
+	fun assoc list key =
+		case
+			List.find (fn (possibility, _) => possibility = key) list
+		of
+			NONE => NONE
+			| SOME (_, answer) => SOME answer
+	local
+		exception NotFound
+	in
+		fun substitute v s =
+			Substitution.substitute
+				(fn s => (case assoc v s of
+					NONE => raise NotFound
+					| SOME x => x
+				)) s
+			handle NotFound => NONE
+	end
+	fun basenameWithoutExtension s = OS.Path.base (OS.Path.file s)
+	local
+		fun index f (string, offset) =
+			let
+				val last = size string
+				fun loop i =
+					if i = last then ~1
+					else if f (String.sub (string, i)) then i
+					else loop (i + 1)
+			in
+				loop offset
+			end
+	in
+		val indexWhitespace = index Char.isSpace
+		val indexNonWhitespace = index (not o Char.isSpace)
+	end
+	fun split2 s =
+		let
+			val f1b = indexNonWhitespace (s, 0)
+		in
+			if f1b = ~1 then NONE
+			else let
+				val f1e = indexWhitespace (s, f1b + 1)
+			in
+				if f1e = ~1 then NONE
+				else let
+					val f2b = indexNonWhitespace (s, f1e + 1)
+				in
+					if f2b = ~1 then NONE
+					else let
+						val f2e = indexWhitespace (s, f2b + 1)
+					in
+						if f2e = ~1 then SOME (
+							substring (s, f1b, f1e - f1b)
+							, substring (s, f2b, size s - f2b)
+						) else if indexNonWhitespace (s, f2e + 1) = ~1 then
+							SOME (
+								substring (s, f1b, f1e - f1b)
+								, substring (s, f2b, f2e - f2b)
+							)
+						else NONE
+					end
+				end
+			end
+		end
+	fun longestCommonSubstring strings =
+		case
+			foldl (fn (a, b) => (case b of
+				NONE => SOME a
+				| SOME b => if size a < size b then SOME a else SOME b
+			)) NONE strings
+		of
+			NONE => ""
+			| SOME shortest => let
+				val minimumSize = size shortest
+				fun loop (size, offset) =
+					let
+						fun next () =
+							if size + offset = minimumSize then
+								loop (size - 1, 0)
+							else loop (size, offset + 1)
+						val sub = substring (shortest, offset, size)
+					in
+						if List.all (String.isSubstring sub) strings then sub
+						else next ()
+					end
+			in
+				loop (minimumSize, 0)
+			end
+end