shader: Refactoring: Let parseDecl return statements

internal/shader/shader.go

@@ -148,9 +148,11 @@ func (cs *compileState) parse(f *ast.File) {
 	// Parse GenDecl for global variables, and then parse functions.
 	for _, d := range f.Decls {
 		if _, ok := d.(*ast.FuncDecl); !ok {
-			if !cs.parseDecl(&cs.global, d) {
+			ss, ok := cs.parseDecl(&cs.global, d)
+			if !ok {
 				return
 			}
+			cs.global.ir.Stmts = append(cs.global.ir.Stmts, ss...)
 		}
 	}
 
@@ -209,9 +211,11 @@ func (cs *compileState) parse(f *ast.File) {
 	// Parse functions.
 	for _, d := range f.Decls {
 		if _, ok := d.(*ast.FuncDecl); ok {
-			if !cs.parseDecl(&cs.global, d) {
+			ss, ok := cs.parseDecl(&cs.global, d)
+			if !ok {
 				return
 			}
+			cs.global.ir.Stmts = append(cs.global.ir.Stmts, ss...)
 		}
 	}
 
@@ -224,7 +228,9 @@ func (cs *compileState) parse(f *ast.File) {
 	}
 }
 
-func (cs *compileState) parseDecl(b *block, d ast.Decl) bool {
+func (cs *compileState) parseDecl(b *block, d ast.Decl) ([]shaderir.Stmt, bool) {
+	var stmts []shaderir.Stmt
+
 	switch d := d.(type) {
 	case *ast.GenDecl:
 		switch d.Tok {
@@ -247,11 +253,11 @@ func (cs *compileState) parseDecl(b *block, d ast.Decl) bool {
 		case token.VAR:
 			for _, s := range d.Specs {
 				s := s.(*ast.ValueSpec)
-				vs, inits, stmts, ok := cs.parseVariable(b, s)
+				vs, inits, ss, ok := cs.parseVariable(b, s)
 				if !ok {
-					return false
+					return nil, false
 				}
-				b.ir.Stmts = append(b.ir.Stmts, stmts...)
+				stmts = append(stmts, ss...)
 				if b == &cs.global {
 					// TODO: Should rhs be ignored?
 					for i, v := range vs {
@@ -271,7 +277,7 @@ func (cs *compileState) parseDecl(b *block, d ast.Decl) bool {
 
 				if len(inits) > 0 {
 					for i := range vs {
-						b.ir.Stmts = append(b.ir.Stmts, shaderir.Stmt{
+						stmts = append(stmts, shaderir.Stmt{
 							Type: shaderir.Assign,
 							Exprs: []shaderir.Expr{
 								{
@@ -292,11 +298,11 @@ func (cs *compileState) parseDecl(b *block, d ast.Decl) bool {
 	case *ast.FuncDecl:
 		f, ok := cs.parseFunc(b, d)
 		if !ok {
-			return false
+			return nil, false
 		}
 		if b != &cs.global {
 			cs.addError(d.Pos(), "non-global function is not implemented")
-			return false
+			return nil, false
 		}
 		switch d.Name.Name {
 		case cs.vertexEntry:
@@ -316,10 +322,10 @@ func (cs *compileState) parseDecl(b *block, d ast.Decl) bool {
 		}
 	default:
 		cs.addError(d.Pos(), "unexpected decl")
-		return false
+		return nil, false
 	}
 
-	return true
+	return stmts, true
 }
 
 // functionReturnTypes returns the original returning value types, if the given expression is call.

internal/shader/stmt.go

@@ -107,9 +107,11 @@ func (cs *compileState) parseStmt(block *block, stmt ast.Stmt, inParams []variab
 			},
 		})
 	case *ast.DeclStmt:
-		if !cs.parseDecl(block, stmt.Decl) {
+		ss, ok := cs.parseDecl(block, stmt.Decl)
+		if !ok {
 			return nil, false
 		}
+		stmts = append(stmts, ss...)
 	case *ast.IfStmt:
 		if stmt.Init != nil {
 			init := stmt.Init