shader: Parse block variables

internal/shader/block.go

@@ -0,0 +1,42 @@
+// Copyright 2020 The Ebiten Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package shader
+
+import (
+	"fmt"
+	"go/token"
+	"strings"
+)
+
+type block struct {
+	vars  []variable
+	stmts []stmt
+	pos   token.Pos
+}
+
+func (b *block) dump(indent int) []string {
+	idt := strings.Repeat("\t", indent)
+
+	var lines []string
+
+	for _, v := range b.vars {
+		lines = append(lines, fmt.Sprintf("%svar %s %s", idt, v.name, v.typ))
+	}
+
+	return lines
+}
+
+type stmt struct {
+}

internal/shader/shader.go

@@ -43,6 +43,7 @@ type function struct {
 	name string
 	args []variable
 	rets []variable
+	body *block
 }
 
 type Shader struct {
@@ -89,6 +90,9 @@ func NewShader(src []byte) (*Shader, error) {
 		return nil, &ParseError{s.errs}
 	}
 
+	// TODO: Resolve identifiers?
+	// TODO: Resolve constants
+
 	sort.Slice(s.varyings, func(a, b int) bool {
 		return s.varyings[a].name < s.varyings[b].name
 	})
@@ -129,7 +133,14 @@ func (sh *Shader) parse(f *ast.File) {
 			case token.VAR:
 				for _, s := range d.Specs {
 					s := s.(*ast.ValueSpec)
-					sh.parseTopLevelVariable(s)
+					vs := sh.parseVariable(s)
+					for _, v := range vs {
+						if 'A' <= v.name[0] && v.name[0] <= 'Z' {
+							sh.uniforms = append(sh.uniforms, v)
+						} else {
+							sh.globals = append(sh.globals, v)
+						}
+					}
 				}
 			case token.IMPORT:
 				sh.addError(d.Pos(), "import is forbidden")
@@ -200,25 +211,26 @@ func (sh *Shader) parseVaryingStruct(t *ast.TypeSpec) {
 	}
 }
 
-func (s *Shader) parseTopLevelVariable(vs *ast.ValueSpec) {
-	t, err := parseType(vs.Type)
-	if err != nil {
-		s.addError(vs.Type.Pos(), err.Error())
-		return
+func (s *Shader) parseVariable(vs *ast.ValueSpec) []variable {
+	var t typ
+	if vs.Type != nil {
+		var err error
+		t, err = parseType(vs.Type)
+		if err != nil {
+			s.addError(vs.Type.Pos(), err.Error())
+			return nil
+		}
 	}
+
+	var vars []variable
 	for _, n := range vs.Names {
 		name := n.Name
-		val := variable{
+		vars = append(vars, 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)
-		}
+		})
 	}
+	return vars
 }
 
 func (s *Shader) parseTopLevelConstant(vs *ast.ValueSpec) {
@@ -302,10 +314,51 @@ func (sh *Shader) parseFunc(d *ast.FuncDecl) {
 		name: d.Name.Name,
 		args: args,
 		rets: rets,
+		body: sh.parseBlock(d.Body),
 	}
 	sh.funcs = append(sh.funcs, f)
 }
 
+func (sh *Shader) parseBlock(b *ast.BlockStmt) *block {
+	block := &block{}
+
+	for _, l := range b.List {
+		switch l := l.(type) {
+		case *ast.AssignStmt:
+			if l.Tok == token.DEFINE {
+				for _, s := range l.Lhs {
+					ident := s.(*ast.Ident)
+					block.vars = append(block.vars, variable{
+						name: ident.Name,
+					})
+				}
+			} else {
+				// TODO
+			}
+		case *ast.DeclStmt:
+			switch d := l.Decl.(type) {
+			case *ast.GenDecl:
+				switch d.Tok {
+				case token.VAR:
+					for _, s := range d.Specs {
+						s := s.(*ast.ValueSpec)
+						vs := sh.parseVariable(s)
+						block.vars = append(block.vars, vs...)
+					}
+				}
+			}
+		case *ast.ReturnStmt:
+		default:
+		}
+	}
+
+	sort.Slice(block.vars, func(a, b int) bool {
+		return block.vars[a].name < block.vars[b].name
+	})
+
+	return block
+}
+
 // Dump dumps the shader state in an intermediate language.
 func (s *Shader) Dump() string {
 	var lines []string
@@ -348,7 +401,10 @@ func (s *Shader) Dump() string {
 		if len(rets) > 0 {
 			l += " (" + strings.Join(rets, ", ") + ")"
 		}
+		l += " {"
 		lines = append(lines, l)
+		lines = append(lines, f.body.dump(1)...)
+		lines = append(lines, "}")
 	}
 
 	return strings.Join(lines, "\n") + "\n"

internal/shader/shader_test.go

@@ -44,7 +44,11 @@ var (
 const C1 float = 1
 const C2, C3 float = 2, 3
 
-func foo(a, b vec2) vec4 {
+func F1(a, b vec2) vec4 {
+	var c0 vec2 = a
+	var c1 = b
+	c2 := vec4{c0, c1}
+	return c2
 }
 `,
 			Dump: `var Position varying vec4 // position
@@ -58,7 +62,11 @@ const C1 float = 1
 const C2 float = 2
 const C3 float = 3
 var qux vec4
-func foo(a vec2, b vec2) (_ vec4)
+func F1(a vec2, b vec2) (_ vec4) {
+	var c0 vec2
+	var c1 (none)
+	var c2 (none)
+}
 `,
 		},
 	}

internal/shader/type.go

@@ -24,8 +24,7 @@ type typ int
 // TODO: What about array types?
 
 const (
-	typBool typ = iota
-	typInt
+	typNone typ = iota
 	typFloat
 	typVec2
 	typVec3
@@ -40,10 +39,6 @@ func parseType(expr ast.Expr) (typ, error) {
 	switch t := expr.(type) {
 	case *ast.Ident:
 		switch t.Name {
-		case "bool":
-			return typBool, nil
-		case "int":
-			return typInt, nil
 		case "float":
 			return typFloat, nil
 		case "vec2":
@@ -68,10 +63,8 @@ func parseType(expr ast.Expr) (typ, error) {
 
 func (t typ) String() string {
 	switch t {
-	case typBool:
-		return "bool"
-	case typInt:
-		return "int"
+	case typNone:
+		return "(none)"
 	case typFloat:
 		return "float"
 	case typVec2:
@@ -94,15 +87,13 @@ func (t typ) String() string {
 }
 
 func (t typ) numeric() bool {
-	return t != typSampler2d
+	return t != typNone && t != typSampler2d
 }
 
 func (t typ) glslString() string {
 	switch t {
-	case typBool:
-		return "bool"
-	case typInt:
-		return "int"
+	case typNone:
+		return "?(none)"
 	case typFloat:
 		return "float"
 	case typVec2: