From 2dc6cbe51aae26483a8bd7da3cf943d2e23385df Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Wed, 29 Jul 2020 12:02:07 +0900
Subject: [PATCH] shader: Make parseType return a boolean value indicating ok

---
 internal/shader/shader.go | 27 ++++++++++++++++++-----
 internal/shader/type.go   | 45 +++++++++++++++++++++------------------
 2 files changed, 46 insertions(+), 26 deletions(-)

diff --git a/internal/shader/shader.go b/internal/shader/shader.go
index e8e8a4b46..5f963ec38 100644
--- a/internal/shader/shader.go
+++ b/internal/shader/shader.go
@@ -260,7 +260,10 @@ func (cs *compileState) parseDecl(b *block, d ast.Decl) ([]shaderir.Stmt, bool)
 			// TODO: Parse other types
 			for _, s := range d.Specs {
 				s := s.(*ast.TypeSpec)
-				t := cs.parseType(b, s.Type)
+				t, ok := cs.parseType(b, s.Type)
+				if !ok {
+					return nil, false
+				}
 				b.types = append(b.types, typ{
 					name: s.Name.Name,
 					ir:   t,
@@ -385,7 +388,11 @@ func (s *compileState) parseVariable(block *block, vs *ast.ValueSpec) ([]variabl
 
 	var declt shaderir.Type
 	if vs.Type != nil {
-		declt = s.parseType(block, vs.Type)
+		var ok bool
+		declt, ok = s.parseType(block, vs.Type)
+		if !ok {
+			return nil, nil, nil, false
+		}
 	}
 
 	var (
@@ -483,7 +490,11 @@ func (s *compileState) parseVariable(block *block, vs *ast.ValueSpec) ([]variabl
 func (s *compileState) parseConstant(block *block, vs *ast.ValueSpec) []constant {
 	var t shaderir.Type
 	if vs.Type != nil {
-		t = s.parseType(block, vs.Type)
+		var ok bool
+		t, ok = s.parseType(block, vs.Type)
+		if !ok {
+			return nil
+		}
 	}
 
 	var cs []constant
@@ -499,7 +510,10 @@ func (s *compileState) parseConstant(block *block, vs *ast.ValueSpec) []constant
 
 func (cs *compileState) parseFuncParams(block *block, d *ast.FuncDecl) (in, out []variable) {
 	for _, f := range d.Type.Params.List {
-		t := cs.parseType(block, f.Type)
+		t, ok := cs.parseType(block, f.Type)
+		if !ok {
+			return
+		}
 		for _, n := range f.Names {
 			in = append(in, variable{
 				name: n.Name,
@@ -513,7 +527,10 @@ func (cs *compileState) parseFuncParams(block *block, d *ast.FuncDecl) (in, out
 	}
 
 	for _, f := range d.Type.Results.List {
-		t := cs.parseType(block, f.Type)
+		t, ok := cs.parseType(block, f.Type)
+		if !ok {
+			return
+		}
 		if len(f.Names) == 0 {
 			out = append(out, variable{
 				name: "",
diff --git a/internal/shader/type.go b/internal/shader/type.go
index 036d983f9..c3b8c3c06 100644
--- a/internal/shader/type.go
+++ b/internal/shader/type.go
@@ -22,72 +22,75 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/shaderir"
 )
 
-func (cs *compileState) parseType(block *block, expr ast.Expr) shaderir.Type {
+func (cs *compileState) parseType(block *block, expr ast.Expr) (shaderir.Type, bool) {
 	switch t := expr.(type) {
 	case *ast.Ident:
 		switch t.Name {
 		case "bool":
-			return shaderir.Type{Main: shaderir.Bool}
+			return shaderir.Type{Main: shaderir.Bool}, true
 		case "int":
-			return shaderir.Type{Main: shaderir.Int}
+			return shaderir.Type{Main: shaderir.Int}, true
 		case "float":
-			return shaderir.Type{Main: shaderir.Float}
+			return shaderir.Type{Main: shaderir.Float}, true
 		case "vec2":
-			return shaderir.Type{Main: shaderir.Vec2}
+			return shaderir.Type{Main: shaderir.Vec2}, true
 		case "vec3":
-			return shaderir.Type{Main: shaderir.Vec3}
+			return shaderir.Type{Main: shaderir.Vec3}, true
 		case "vec4":
-			return shaderir.Type{Main: shaderir.Vec4}
+			return shaderir.Type{Main: shaderir.Vec4}, true
 		case "mat2":
-			return shaderir.Type{Main: shaderir.Mat2}
+			return shaderir.Type{Main: shaderir.Mat2}, true
 		case "mat3":
-			return shaderir.Type{Main: shaderir.Mat3}
+			return shaderir.Type{Main: shaderir.Mat3}, true
 		case "mat4":
-			return shaderir.Type{Main: shaderir.Mat4}
+			return shaderir.Type{Main: shaderir.Mat4}, true
 		default:
 			cs.addError(t.Pos(), fmt.Sprintf("unexpected type: %s", t.Name))
-			return shaderir.Type{}
+			return shaderir.Type{}, false
 		}
 	case *ast.ArrayType:
 		if t.Len == nil {
 			cs.addError(t.Pos(), fmt.Sprintf("array length must be specified"))
-			return shaderir.Type{}
+			return shaderir.Type{}, false
 		}
 		// TODO: Parse ellipsis
 
 		exprs, _, _, ok := cs.parseExpr(block, t.Len)
 		if !ok {
-			return shaderir.Type{}
+			return shaderir.Type{}, false
 		}
 		if len(exprs) != 1 {
 			cs.addError(t.Pos(), fmt.Sprintf("invalid length of array"))
-			return shaderir.Type{}
+			return shaderir.Type{}, false
 		}
 		if exprs[0].Type != shaderir.NumberExpr {
 			cs.addError(t.Pos(), fmt.Sprintf("length of array must be a constant number"))
-			return shaderir.Type{}
+			return shaderir.Type{}, false
 		}
 		len, ok := gconstant.Int64Val(exprs[0].Const)
 		if !ok {
 			cs.addError(t.Pos(), fmt.Sprintf("length of array must be an integer"))
-			return shaderir.Type{}
+			return shaderir.Type{}, false
 		}
 
-		elm := cs.parseType(block, t.Elt)
+		elm, ok := cs.parseType(block, t.Elt)
+		if !ok {
+			return shaderir.Type{}, false
+		}
 		if elm.Main == shaderir.Array {
 			cs.addError(t.Pos(), fmt.Sprintf("array of array is forbidden"))
-			return shaderir.Type{}
+			return shaderir.Type{}, false
 		}
 		return shaderir.Type{
 			Main:   shaderir.Array,
 			Sub:    []shaderir.Type{elm},
 			Length: int(len),
-		}
+		}, true
 	case *ast.StructType:
 		cs.addError(t.Pos(), "struct is not implemented")
-		return shaderir.Type{}
+		return shaderir.Type{}, false
 	default:
 		cs.addError(t.Pos(), fmt.Sprintf("unepxected type: %v", t))
-		return shaderir.Type{}
+		return shaderir.Type{}, false
 	}
 }