finals but like actual finals

Author: KoloInDaCrib

hscript/Expr.hx

@@ -43,6 +43,7 @@ enum Expr {
 	EConst( c : Const );
 	EIdent( v : String );
 	EVar( n : String, ?t : CType, ?e : Expr );
+	EFinal( n : String, ?t : CType, ?e : Expr );
 	EParent( e : Expr );
 	EBlock( e : Array<Expr> );
 	EField( e : Expr, f : String );
@@ -174,4 +175,5 @@ typedef VarDecl = {
 	var set : Null<String>;
 	var expr : Null<Expr>;
 	var type : Null<CType>;
+	var isfinal : Null<Bool>;
 }

hscript/Interp.hx

@@ -33,12 +33,12 @@ private enum Stop {
 class Interp {
 
 	public var variables : Map<String,Dynamic>;
-	var locals : Map<String,{ r : Dynamic }>;
+	var locals : Map<String,{ r : Dynamic, ?isfinal : Bool }>;
 	var binops : Map<String, Expr -> Expr -> Dynamic >;
 
 	var depth : Int;
 	var inTry : Bool;
-	var declared : Array<{ n : String, old : { r : Dynamic } }>;
+	var declared : Array<{ n : String, old : { r : Dynamic, ?isfinal : Bool } }>;
 	var returnValue : Dynamic;
 
 	#if hscriptPos
@@ -122,6 +122,7 @@ class Interp {
 		switch( Tools.expr(e1) ) {
 		case EIdent(id):
 			var l = locals.get(id);
+			if( l != null && l.isfinal && l.r != null) return error(EInvalidAccess(id));
 			if( l == null )
 				setVar(id,v)
 			else
@@ -155,6 +156,7 @@ class Interp {
 		case EIdent(id):
 			var l = locals.get(id);
 			v = fop(expr(e1),expr(e2));
+			if( l != null && l.isfinal && l.r != null) return error(EInvalidAccess(id));
 			if( l == null )
 				setVar(id,v)
 			else
@@ -189,6 +191,7 @@ class Interp {
 		case EIdent(id):
 			var l = locals.get(id);
 			var v : Dynamic = (l == null) ? resolve(id) : l.r;
+			if( l != null && l.isfinal && l.r != null) return error(EInvalidAccess(id));
 			if( prefix ) {
 				v += delta;
 				if( l == null ) setVar(id,v) else l.r = v;
@@ -311,6 +314,10 @@ class Interp {
 			declared.push({ n : n, old : locals.get(n) });
 			locals.set(n,{ r : (e == null)?null:expr(e) });
 			return null;
+		case EFinal(n,_,e):
+			declared.push({ n : n, old : locals.get(n) });
+			locals.set(n,{ r : (e == null)?null:expr(e), isfinal : true });
+			return null;
 		case EParent(e):
 			return expr(e);
 		case EBlock(exprs):

hscript/Parser.hx

@@ -267,7 +267,7 @@ class Parser {
 		return switch( expr(e) ) {
 		case EBlock(_), EObject(_), ESwitch(_): true;
 		case EFunction(_,e,_,_): isBlock(e);
-		case EVar(_, t, e): e != null ? isBlock(e) : t != null ? t.match(CTAnon(_)) : false;
+		case EVar(_, t, e) | EFinal(_, t, e): e != null ? isBlock(e) : t != null ? t.match(CTAnon(_)) : false;
 		case EIf(_,e1,e2): if( e2 != null ) isBlock(e2) else isBlock(e1);
 		case EBinop(_,_,e): isBlock(e);
 		case EUnop(_,prefix,e): !prefix && isBlock(e);
@@ -614,6 +614,27 @@ class Parser {
 			}
 
 			mk(EVar(ident,t,e),p1,(e == null) ? tokenMax : pmax(e));
+		case "final":
+			var ident = getIdent();
+			var tk = token();
+			var t = null;
+			if( tk == TDoubleDot && allowTypes ) {
+				t = parseType();
+				tk = token();
+			}
+			var e = null;
+	
+			switch (tk)
+			{
+				case TOp("="): e = parseExpr();
+				case TOp(_): unexpected(tk);
+				case TComma | TSemicolon: push(tk);
+				// Above case should be enough but semicolon is not mandatory after }
+				case _ if (t != null): push(tk);
+				default: unexpected(tk);
+			}
+	
+			mk(EFinal(ident,t,e),p1,(e == null) ? tokenMax : pmax(e));
 		case "while":
 			var econd = parseExpr();
 			var e = parseExpr();
@@ -1225,7 +1246,7 @@ class Parser {
 						ret : inf.ret,
 					}),
 				};
-			case "var":
+			case "var" | "final":
 				var name = getIdent();
 				var get = null, set = null;
 				if( maybe(TPOpen) ) {
@@ -1256,6 +1277,7 @@ class Parser {
 						set : set,
 						type : type,
 						expr : expr,
+						isfinal : (id == "final")
 					}),
 				};
 			default:

hscript/Printer.hx

@@ -129,6 +129,13 @@ class Printer {
 				add(" = ");
 				expr(e);
 			}
+		case EFinal(n, t, e):
+			add("final " + n);
+			addType(t);
+			if( e != null ) {
+				add(" = ");
+				expr(e);
+			}
 		case EParent(e):
 			add("("); expr(e); add(")");
 		case EBlock(el):

hscript/Tools.hx

@@ -27,7 +27,7 @@ class Tools {
 	public static function iter( e : Expr, f : Expr -> Void ) {
 		switch( expr(e) ) {
 		case EConst(_), EIdent(_):
-		case EVar(_, _, e): if( e != null ) f(e);
+		case EVar(_, _, e) | EFinal(_, _, e): if( e != null ) f(e);
 		case EParent(e): f(e);
 		case EBlock(el): for( e in el ) f(e);
 		case EField(e, _): f(e);
@@ -64,6 +64,7 @@ class Tools {
 		var edef = switch( expr(e) ) {
 		case EConst(_), EIdent(_), EBreak, EContinue: expr(e);
 		case EVar(n, t, e): EVar(n, t, if( e != null ) f(e) else null);
+		case EFinal(n, t, e): EFinal(n, t, if( e != null ) f(e) else null);
 		case EParent(e): EParent(f(e));
 		case EBlock(el): EBlock([for( e in el ) f(e)]);
 		case EField(e, fi): EField(f(e),fi);