shader: Parse number literals in unary expressions correctly

Fixes #1190

internal/shader/shader.go

@@ -1136,6 +1136,10 @@ func (cs *compileState) parseExpr(block *block, expr ast.Expr) ([]shaderir.Expr,
 			}, nil, nil, true
 		}
 		cs.addError(e.Pos(), fmt.Sprintf("unexpected identifier: %s", e.Name))
+
+	case *ast.ParenExpr:
+		return cs.parseExpr(block, e.X)
+
 	case *ast.SelectorExpr:
 		exprs, _, stmts, ok := cs.parseExpr(block, e.X)
 		if !ok {
@@ -1171,7 +1175,31 @@ func (cs *compileState) parseExpr(block *block, expr ast.Expr) ([]shaderir.Expr,
 				},
 			},
 		}, []shaderir.Type{t}, stmts, true
+
 	case *ast.UnaryExpr:
+		exprs, t, stmts, ok := cs.parseExpr(block, e.X)
+		if !ok {
+			return nil, nil, nil, false
+		}
+		if len(exprs) != 1 {
+			cs.addError(e.Pos(), fmt.Sprintf("multiple-value context is not available at a unary operator: %s", e.X))
+			return nil, nil, nil, false
+		}
+
+		if exprs[0].Type == shaderir.NumberExpr {
+			v := gconstant.UnaryOp(e.Op, exprs[0].Const, 0)
+			t := shaderir.Type{Main: shaderir.Int}
+			if v.Kind() == gconstant.Float {
+				t = shaderir.Type{Main: shaderir.Float}
+			}
+			return []shaderir.Expr{
+				{
+					Type:  shaderir.NumberExpr,
+					Const: v,
+				},
+			}, []shaderir.Type{t}, stmts, true
+		}
+
 		var op shaderir.Op
 		switch e.Op {
 		case token.ADD:
@@ -1184,14 +1212,6 @@ func (cs *compileState) parseExpr(block *block, expr ast.Expr) ([]shaderir.Expr,
 			cs.addError(e.Pos(), fmt.Sprintf("unexpected operator: %s", e.Op))
 			return nil, nil, nil, false
 		}
-		exprs, t, stmts, ok := cs.parseExpr(block, e.X)
-		if !ok {
-			return nil, nil, nil, false
-		}
-		if len(exprs) != 1 {
-			cs.addError(e.Pos(), fmt.Sprintf("multiple-value context is not available at a unary operator: %s", e.X))
-			return nil, nil, nil, false
-		}
 		return []shaderir.Expr{
 			{
 				Type:  shaderir.Unary,

internal/shader/testdata/number_unary.expected.vs

@@ -0,0 +1,41 @@
+void F0(out vec4 l0) {
+	int l1 = 0;
+	int l2 = 0;
+	int l3 = 0;
+	int l4 = 0;
+	float l5 = float(0);
+	float l6 = float(0);
+	float l7 = float(0);
+	float l8 = float(0);
+	l1 = 5;
+	l2 = -5;
+	l3 = -5;
+	l4 = 5;
+	l5 = 5.0;
+	l6 = -5.0;
+	l7 = -5.0;
+	l8 = 5.0;
+	l0 = (vec4(l1, l2, l3, l4)) + (vec4(l5, l6, l7, l8));
+	return;
+}
+
+void F1(out vec4 l0) {
+	int l1 = 0;
+	int l2 = 0;
+	int l3 = 0;
+	int l4 = 0;
+	float l5 = float(0);
+	float l6 = float(0);
+	float l7 = float(0);
+	float l8 = float(0);
+	l1 = 5;
+	l2 = -5;
+	l3 = -5;
+	l4 = 5;
+	l5 = 5.0;
+	l6 = -5.0;
+	l7 = -5.0;
+	l8 = 5.0;
+	l0 = (vec4(l1, l2, l3, l4)) + (vec4(l5, l6, l7, l8));
+	return;
+}

internal/shader/testdata/number_unary.go

@@ -0,0 +1,25 @@
+package main
+
+func Foo1() vec4 {
+	x0 := +(+5)
+	x1 := +(-5)
+	x2 := -(+5)
+	x3 := -(-5)
+	x4 := +(+5.0)
+	x5 := +(-5.0)
+	x6 := -(+5.0)
+	x7 := -(-5.0)
+	return vec4(x0, x1, x2, x3) + vec4(x4, x5, x6, x7)
+}
+
+func Foo2() vec4 {
+	var x0 = +(+5)
+	var x1 = +(-5)
+	var x2 = -(+5)
+	var x3 = -(-5)
+	var x4 = +(+5.0)
+	var x5 = +(-5.0)
+	var x6 = -(+5.0)
+	var x7 = -(-5.0)
+	return vec4(x0, x1, x2, x3) + vec4(x4, x5, x6, x7)
+}