add command line arguments parser

elements.ml

@@ -1,2 +1,39 @@
-let () = Makedb.makedb (Sqlite3.db_open "elements.sqlite3")
-	(Yojson.Basic.from_channel stdin)
+module Opts = struct
+	open Arg
+
+	type lasttype = NAME | SYMB
+
+	let ltype = ref NAME
+	let gendb = ref ""
+	let maxmatch = ref 3
+	let match_name : string list ref = ref []
+	let match_symb : string list ref = ref []
+	let dbfile = ref "elements.sqlite3"
+
+	let add_name s =
+		match_name := s::!match_name;
+		ltype := NAME
+	let add_symb s =
+		match_symb := s::!match_symb;
+		ltype := SYMB
+	let add_def s = match !ltype with
+	| NAME -> add_name s
+	| SYMB -> add_symb s
+
+	let msg = "Periodic table search\n\
+		elements -gendb file [-dbfile outfile]\n\
+		elements [-maxmatch n] [-dbfile search] [-name ...] [-symb ...]\n\
+	"
+
+	let spec = [
+	"-gendb", Set_string gendb, "Generate DB file";
+	"-maxmatch", Set_int maxmatch, "Limit the amount of matches (def. 3)";
+	"-dbfile", Set_string dbfile, "Set the DB filename";
+	"-name", String add_name, "Search by name (default)";
+	"-symb", String add_symb, "Search by symbol"
+	]
+
+	let exec() = parse spec add_def msg
+end
+
+let () = Opts.exec()