feature: refactor api parse to g4 (#365)

* feature: refactor api parse to g4

* new g4 parser

* add CHANGE_LOG.MD

* refactor

* fix byte bug

* refactor

* optimized

* optimized

* revert

* update readme.md

* update readme.md

* update readme.md

* update readme.md

* remove no need

* fix java gen

* add upgrade

* resolve confilits

Co-authored-by: anqiansong <anqiansong@xiaoheiban.cn>

tools/goctl/api/parser/g4/test/syntax_test.go

@@ -0,0 +1,75 @@
+package test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tal-tech/go-zero/tools/goctl/api/parser/g4/ast"
+	"github.com/tal-tech/go-zero/tools/goctl/api/parser/g4/gen/api"
+)
+
+var syntaxAccept = func(p *api.ApiParserParser, visitor *ast.ApiVisitor) interface{} {
+	return p.SyntaxLit().Accept(visitor)
+}
+
+func TestSyntax(t *testing.T) {
+	t.Run("matched", func(t *testing.T) {
+		v, err := parser.Accept(syntaxAccept, `syntax = "v1"`)
+		assert.Nil(t, err)
+
+		syntax := v.(*ast.SyntaxExpr)
+		assert.True(t, syntax.Equal(&ast.SyntaxExpr{
+			Syntax:  ast.NewTextExpr("syntax"),
+			Assign:  ast.NewTextExpr("="),
+			Version: ast.NewTextExpr(`"v1"`),
+		}))
+	})
+
+	t.Run("expecting syntax", func(t *testing.T) {
+		_, err := parser.Accept(syntaxAccept, `= "v1"`)
+		assert.Error(t, err)
+
+		_, err = parser.Accept(syntaxAccept, `syn = "v1"`)
+		assert.Error(t, err)
+	})
+
+	t.Run("missing assign", func(t *testing.T) {
+		_, err := parser.Accept(syntaxAccept, `syntax  "v1"`)
+		assert.Error(t, err)
+
+		_, err = parser.Accept(syntaxAccept, `syntax + "v1"`)
+		assert.Error(t, err)
+	})
+
+	t.Run("mismatched version", func(t *testing.T) {
+		_, err := parser.Accept(syntaxAccept, `syntax="v0"`)
+		assert.Error(t, err)
+
+		_, err = parser.Accept(syntaxAccept, `syntax = "v1a"`)
+		assert.Error(t, err)
+
+		_, err = parser.Accept(syntaxAccept, `syntax = "vv1"`)
+		assert.Error(t, err)
+
+		_, err = parser.Accept(syntaxAccept, `syntax = "1"`)
+		assert.Error(t, err)
+	})
+
+	t.Run("with comment", func(t *testing.T) {
+		v, err := parser.Accept(syntaxAccept, `
+		// doc
+		syntax="v1" // line comment`)
+		assert.Nil(t, err)
+
+		syntax := v.(*ast.SyntaxExpr)
+		assert.True(t, syntax.Equal(&ast.SyntaxExpr{
+			Syntax:  ast.NewTextExpr("syntax"),
+			Assign:  ast.NewTextExpr("="),
+			Version: ast.NewTextExpr(`"v1"`),
+			DocExpr: []ast.Expr{
+				ast.NewTextExpr("// doc"),
+			},
+			CommentExpr: ast.NewTextExpr("// line comment"),
+		}))
+	})
+}