(** Analyse syntaxique **)



(* Analyse lexcicale *)
open Genlex;;

let rec list_of_stream = parser
   | [< 'a; q = list_of_stream >] -> a::q
   | [< >] -> []
;;

let lexer chaîne =
list_of_stream (make_lexer ["("; ")"; "-"; "+"; "/"; "*"; "^"] (Stream.of_string chaîne));;

(* lexer "7 * (5 - 2)";; *)

(* Analyse syntaxique *)
type tree =
	|Tree_int of int        | Tree_float of float
	|Tree_plus of tree*tree | Tree_moins of tree*tree
	|Tree_mult of tree*tree | Tree_divi of tree*tree
	|Tree_expo of tree*tree | Tree_oppo of tree
;;

let read lexemes =
	let reste=ref lexemes and fin=(Kwd "fin") in
	let avancer()=(reste:=tl !reste)
	and terminal_courant ()=match !reste with
		|[] -> fin
		|premier::_ -> premier
in	let rec read_Input()=
		let expr=read_expr() in read_eof expr
		and read_expr()= read_Restexpr (read_nb())
		and read_nb()=match terminal_courant() with
			|Int nb -> avancer(); Tree_int nb
			|Float nb -> avancer(); Tree_float nb
			|_ -> failwith "Erreur : manque un nombre"
		and read_Restexpr arbre =match terminal_courant() with
			|Kwd "+" -> avancer(); read_Restexpr (Tree_plus(arbre, read_nb()))
			|Kwd "-" -> avancer(); read_Restexpr (Tree_moins(arbre, read_nb()))
			|Kwd "*" -> avancer(); read_Restexpr (Tree_mult(arbre, read_nb()))
			|Kwd "/" -> avancer(); read_Restexpr (Tree_divi(arbre, read_nb()))
			|_ -> arbre
		and read_eof arbre =
			if terminal_courant()=fin then arbre else failwith "Pas de fin"
in	read_Input();;

let read_fct lexemes =
	let fin=Kwd "fin" in
	let avancer (_,liste) = match liste with
		|[]	-> (fin,liste)
		|t::q -> (t,q)
	and terminal_courant = function
		|[] -> fin
		|premier::_ -> premier
in	let rec read_Input lex_liste=
		let expr = begin let (a,new) = read_nb (Int 0, lex_liste) in read_Restexpr a new end
		in if (fst expr)=fin then (snd expr) else failwith "Pas de fin"
		and read_nb couple = let (x,l)=avancer couple in
			match x with
				|Int nb -> (Tree_int nb,avancer (x,l))
				|Float nb -> (Tree_float nb,avancer (x,l))
				|_ -> failwith "Erreur : manque un nombre"
		and read_Restexpr arbre (x,l) = match x with
			|Kwd "+" -> (let (b,new)=read_nb (x,l) in read_Restexpr (Tree_plus(arbre, b)) new)
			|Kwd "-" -> (let (b,new)=read_nb (x,l) in	read_Restexpr (Tree_moins(arbre, b)) new)
			|Kwd "*" -> (let (b,new)=read_nb (x,l) in read_Restexpr (Tree_mult(arbre, b)) new)
			|Kwd "/" -> (let (b,new)=read_nb (x,l) in	read_Restexpr (Tree_divi(arbre, b)) new)
			|_ -> (x,arbre)
in	read_Input lexemes;;

read_fct (lexer "1 - 2 + 3");;