From ad820abce5588b09ba7034f97de7eea71417ff5e Mon Sep 17 00:00:00 2001
From: Christopher Seven Phiri <chris7phiri@gmail.com>
Date: Thu, 15 Aug 2024 12:28:18 +0200
Subject: [PATCH] can parse classes

---
 src/ast/class.go          | 31 +++++++++++++++++++++++++++++++
 src/parser/class.go       | 24 ++++++++++++++++++++++++
 src/parser/parser.go      |  1 +
 src/parser/parser_test.go | 18 ++++++++++--------
 src/token/token.go        |  2 ++
 5 files changed, 68 insertions(+), 8 deletions(-)
 create mode 100644 src/ast/class.go
 create mode 100644 src/parser/class.go

diff --git a/src/ast/class.go b/src/ast/class.go
new file mode 100644
index 0000000..b9d159d
--- /dev/null
+++ b/src/ast/class.go
@@ -0,0 +1,31 @@
+package ast
+
+import (
+	"bytes"
+
+	"github.com/sevenreup/chewa/src/token"
+)
+
+type ClassStatement struct {
+	Expression
+	Token token.Token
+	Name  *Identifier
+	Super *Identifier
+	Body  *BlockStatement
+}
+
+func (class *ClassStatement) expressionNode()      {}
+func (class *ClassStatement) TokenLiteral() string { return class.Token.Literal }
+func (class *ClassStatement) String() string {
+	var out bytes.Buffer
+	out.WriteString("ndondomeko ")
+	out.WriteString(class.Name.String())
+	if class.Super != nil {
+		out.WriteString(" ndi ")
+		out.WriteString(class.Super.String())
+	}
+	out.WriteString(" {\n")
+	out.WriteString(class.Body.String())
+	out.WriteString("\n}")
+	return out.String()
+}
diff --git a/src/parser/class.go b/src/parser/class.go
new file mode 100644
index 0000000..0cd09d9
--- /dev/null
+++ b/src/parser/class.go
@@ -0,0 +1,24 @@
+package parser
+
+import (
+	"github.com/sevenreup/chewa/src/ast"
+	"github.com/sevenreup/chewa/src/token"
+)
+
+func (p *Parser) classStatement() ast.Expression {
+	class := &ast.ClassStatement{Token: p.curToken}
+
+	p.nextToken()
+
+	class.Name = &ast.Identifier{Token: p.curToken, Value: p.curToken.Literal}
+
+	// TODO: Implement inheritance
+
+	if !p.expectPeek(token.OPENING_BRACE) {
+		return nil
+	}
+
+	class.Body = p.parseBlockStatement()
+
+	return class
+}
diff --git a/src/parser/parser.go b/src/parser/parser.go
index 1b5142a..113491f 100644
--- a/src/parser/parser.go
+++ b/src/parser/parser.go
@@ -85,6 +85,7 @@ func New(l *lexer.Lexer) *Parser {
 	p.registerPrefix(token.FOR, p.parseForExpression)
 	p.registerPrefix(token.WHILE, p.parseWhileExpression)
 	p.registerPrefix(token.FUNCTION, p.parseFunctionLiteral)
+	p.registerPrefix(token.CLASS, p.classStatement)
 	
 	p.registerPrefix(token.OPENING_BRACE, p.mapLiteral)
 	p.registerPrefix(token.OPENING_PAREN, p.parseGroupedExpression)
diff --git a/src/parser/parser_test.go b/src/parser/parser_test.go
index 9eb340e..e1c5da0 100644
--- a/src/parser/parser_test.go
+++ b/src/parser/parser_test.go
@@ -1346,24 +1346,26 @@ func TestParsingHashLiteralsWithExpressions(t *testing.T) {
 
 func TestParsingClassExpressions(t *testing.T) {
 	input := `
-		kalasi Person { 
+		kalasi Person {
+			nambala age = 5;
 		}`
 	l := lexer.New([]byte(input))
 	p := New(l)
 	program := p.ParseProgram()
 	checkParserErrors(t, p)
-	stmt := program.Statements[0].(*ast.ClassStatement)
-	if stmt.Name.Value != "Person" {
-		t.Fatalf("stmt.Name.Value not 'Person'. got=%q", stmt.Name.Value)
+	stmt := program.Statements[0].(*ast.ExpressionStatement)
+	classStatement := stmt.Expression.(*ast.ClassStatement)
+	if classStatement.Name.Value != "Person" {
+		t.Fatalf("stmt.Name.Value not 'Person'. got=%q", classStatement.Name.Value)
 	}
-	if len(stmt.Body.Statements) != 1 {
+	if len(classStatement.Body.Statements) != 1 {
 		t.Fatalf("stmt.Body.Statements does not contain 1 statements. got=%d\n",
-			len(stmt.Body.Statements))
+			len(classStatement.Body.Statements))
 	}
-	bodyStmt, ok := stmt.Body.Statements[0].(*ast.VariableDeclarationStatement)
+	bodyStmt, ok := classStatement.Body.Statements[0].(*ast.VariableDeclarationStatement)
 	if !ok {
 		t.Fatalf("stmt.Body.Statements[0] is not ast.VariableDeclarationStatement. got=%T",
-			stmt.Body.Statements[0])
+			classStatement.Body.Statements[0])
 	}
 	if bodyStmt.Identifier.Value != "age" {
 		t.Fatalf("bodyStmt.Identifier.Value not 'age'. got=%s", bodyStmt.Identifier.Value)
diff --git a/src/token/token.go b/src/token/token.go
index 3daaac0..0272162 100644
--- a/src/token/token.go
+++ b/src/token/token.go
@@ -63,6 +63,7 @@ const (
 	FOR      = "FOR"
 	WHILE    = "WHILE"
 	MAP      = "MAP"
+	CLASS    = "CLASS"
 )
 
 type Position struct {
@@ -89,6 +90,7 @@ var keywords = map[string]TokenType{
 	"za":         FOR,
 	"pamene":     WHILE,
 	"mgwirizano": MAP,
+	"kalasi":     CLASS,
 }
 
 var variableTypes = map[TokenType]TokenType{