(* Database.sml *) datatype component =     Str					(* structure                       *)  | Exc of string			(* exception constructor with name *)  | Typ of string			(* type constructor with name      *)  | Val of string			(* value with name                 *)  | Con of string			(* value constructor with name	   *)  | Term of string * string option	(* term and optional kind          *) (* An entry consist of a component and the name of its structure: *) type entry = { comp : component, file : string, line : int } (* Table represented by ordered binary tree, where key is lowercase: *) datatype 'contents table =    Empty  | Node of string * 'contents * 'contents table * 'contents table (* The database is a table of sorted lists of entries: *) type database = entry list table fun writebase(filename, db) =    let val os = BasicIO.open_out_bin filename    in Nonstdio.output_value os db; BasicIO.close_out os end fun readbase filename =    let open BasicIO	prim_type in_channel 	type instream_  = { closed: bool, ic: in_channel } ref	prim_val input_value_ : in_channel -> 'a = 1 "intern_val"	prim_val fromI : instream -> instream_   = 1 "identity"        fun input_value is =	    let val ref {closed, ic} = fromI is in		if closed then		    raise SysErr("Input stream is closed", NONE)		else		    input_value_ ic	    end	val is = open_in_bin filename	val db = input_value is : database    in close_in is; db end (* Make sure tilde gets collated as a symbol, before "A": *) fun caseless(#"~", #"~") = EQUAL  | caseless(#"~", c2) =     if Char.toLower c2 < #"a" then GREATER else LESS  | caseless(c1, #"~") =     if Char.toLower c1 < #"a" then LESS else GREATER  | caseless(c1, c2) = Char.compare(Char.toLower c1, Char.toLower c2) val keycompare = String.collate caseless fun lookup(db : database, sought : string) =    let fun look Empty                      = []	  | look (Node(key, value, t1, t2)) =	    case keycompare(sought, key) of		LESS    => look t1	      | GREATER => look t2	      | EQUAL   => value    in look db end (* Extract the name from an entry: *) fun getname ({comp, file, ...} : entry) =    case comp of	Str    => file      | Exc id => id      | Typ id => id      | Val id => id      | Con id => id      | Term (id, _) => id