From 1b2c29f6f3e665db40ad85626852c2f9b61c623e Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 9 May 2020 17:32:10 +0900
Subject: [PATCH] shader: Refactoring

---
 internal/shader/shader.go | 97 +++++++++++++++++++--------------------
 1 file changed, 48 insertions(+), 49 deletions(-)

diff --git a/internal/shader/shader.go b/internal/shader/shader.go
index f7d705f54..f141ee1a1 100644
--- a/internal/shader/shader.go
+++ b/internal/shader/shader.go
@@ -100,32 +100,40 @@ func (s *Shader) addError(pos token.Pos, str string) {
 	s.errs = append(s.errs, fmt.Sprintf("%s: %s", p, str))
 }
 
-func (s *Shader) parse(f *ast.File) {
-	for name, obj := range f.Scope.Objects {
-		switch name {
-		case varyingStructName:
-			s.parseVaryingStruct(obj)
-		default:
-			switch obj.Kind {
-			case ast.Con:
-				s.parsePackageLevelConstant(name, obj)
-			case ast.Var:
-				s.parsePackageLevelVariable(name, obj)
+func (sh *Shader) parse(f *ast.File) {
+	for _, d := range f.Decls {
+		switch d := d.(type) {
+		case *ast.GenDecl:
+			switch d.Tok {
+			case token.TYPE:
+				// TODO: Parse regular structs or other types
+				for _, s := range d.Specs {
+					s := s.(*ast.TypeSpec)
+					if s.Name.Name == varyingStructName {
+						sh.parseVaryingStruct(s)
+					}
+				}
+			case token.CONST:
+				for _, s := range d.Specs {
+					s := s.(*ast.ValueSpec)
+					sh.parsePackageLevelConstant(s)
+				}
+			case token.VAR:
+				for _, s := range d.Specs {
+					s := s.(*ast.ValueSpec)
+					sh.parsePackageLevelVariable(s)
+				}
 			}
+		default:
+			// TODO: Parse functions
 		}
 	}
 }
 
-func (sh *Shader) parseVaryingStruct(obj *ast.Object) {
-	name := obj.Name
-	if obj.Kind != ast.Typ {
-		sh.addError(obj.Pos(), fmt.Sprintf("%s must be a type but %s", name, obj.Kind))
-		return
-	}
-	t := obj.Decl.(*ast.TypeSpec).Type
-	s, ok := t.(*ast.StructType)
+func (sh *Shader) parseVaryingStruct(t *ast.TypeSpec) {
+	s, ok := t.Type.(*ast.StructType)
 	if !ok {
-		sh.addError(t.Pos(), fmt.Sprintf("%s must be a struct but not", name))
+		sh.addError(t.Type.Pos(), fmt.Sprintf("%s must be a struct but not", t.Name))
 		return
 	}
 
@@ -178,45 +186,35 @@ func (sh *Shader) parseVaryingStruct(obj *ast.Object) {
 	}
 }
 
-func (s *Shader) parsePackageLevelVariable(name string, obj *ast.Object) {
-	v, ok := obj.Decl.(*ast.ValueSpec)
-	if !ok {
-		s.addError(obj.Pos(), "value spec expected")
-		return
-	}
-	t, err := parseType(v.Type)
+func (s *Shader) parsePackageLevelVariable(vs *ast.ValueSpec) {
+	t, err := parseType(vs.Type)
 	if err != nil {
-		s.addError(v.Type.Pos(), err.Error())
+		s.addError(vs.Type.Pos(), err.Error())
 		return
 	}
-	val := variable{
-		name: name,
-		typ:  t,
-	}
-	// TODO: Parse initial value.
-	if 'A' <= name[0] && name[0] <= 'Z' {
-		s.uniforms = append(s.uniforms, val)
-	} else {
-		s.globals = append(s.globals, val)
+	for _, n := range vs.Names {
+		name := n.Name
+		val := variable{
+			name: name,
+			typ:  t,
+		}
+		// TODO: Parse initial value.
+		if 'A' <= name[0] && name[0] <= 'Z' {
+			s.uniforms = append(s.uniforms, val)
+		} else {
+			s.globals = append(s.globals, val)
+		}
 	}
 }
 
-func (s *Shader) parsePackageLevelConstant(name string, obj *ast.Object) {
-	vs, ok := obj.Decl.(*ast.ValueSpec)
-	if !ok {
-		s.addError(obj.Pos(), "value spec expected")
-		return
-	}
+func (s *Shader) parsePackageLevelConstant(vs *ast.ValueSpec) {
 	t, err := parseType(vs.Type)
 	if err != nil {
-		s.addError(vs.Pos(), err.Error())
+		s.addError(vs.Type.Pos(), err.Error())
 		return
 	}
-	for i, v := range vs.Values {
-		if vs.Names[i].Name != name {
-			continue
-		}
-
+	for i, n := range vs.Names {
+		v := vs.Values[i]
 		var init string
 		switch v := v.(type) {
 		case *ast.BasicLit:
@@ -228,6 +226,7 @@ func (s *Shader) parsePackageLevelConstant(name string, obj *ast.Object) {
 		default:
 			// TODO: Parse the expression.
 		}
+		name := n.Name
 		val := variable{
 			name:     name,
 			typ:      t, // TODO: Treat consts without types