Merge pull request #6 from looplanguage/feat/assign_index

feat: add array index assigning

Author: kanersps

models/ast/assign.go

@@ -16,3 +16,16 @@ func (vd *Assign) TokenLiteral() string { return vd.Token.Name() }
 func (vd *Assign) String() string {
 	return fmt.Sprintf("%v = %v", vd.Identifier.Value, vd.Value.String())
 }
+
+type IndexAssign struct {
+	Token  tokens.Token
+	Object Expression
+	Index  Expression
+	Value  Expression
+}
+
+func (vd *IndexAssign) statementNode()       {}
+func (vd *IndexAssign) TokenLiteral() string { return vd.Token.Name() }
+func (vd *IndexAssign) String() string {
+	return fmt.Sprintf("%v = %v", vd.Object.String(), vd.Value.String())
+}

parser/parse_array.go

@@ -48,6 +48,7 @@ func (p *Parser) parseIndexExpression(left ast.Expression) ast.Expression {
 	}
 
 	p.NextToken()
+
 	if p.CurrentToken.Type != tokens.RightBracket {
 		p.AddError(fmt.Sprintf("wrong token. expected=%q. got=%q", "]", p.CurrentToken.Literal))
 		return nil

parser/parse_statement.go

@@ -29,7 +29,7 @@ func (p *Parser) parseStatement() ast.Statement {
 	}
 }
 
-func (p *Parser) parseExpressionStatement() *ast.ExpressionStatement {
+func (p *Parser) parseExpressionStatement() ast.Statement {
 	expression := &ast.ExpressionStatement{
 		Token: p.CurrentToken,
 	}
@@ -40,6 +40,23 @@ func (p *Parser) parseExpressionStatement() *ast.ExpressionStatement {
 		p.NextToken()
 	}
 
+	if arr, ok := expression.Expression.(*ast.IndexExpression); ok {
+		fmt.Println(":)")
+		if p.peekTokenIs(tokens.Assign) {
+			p.NextToken()
+			p.NextToken()
+
+			value := p.parseExpression(precedence.LOWEST)
+
+			return &ast.IndexAssign{
+				Token:  p.CurrentToken,
+				Object: arr.Value,
+				Index:  arr.Index,
+				Value:  value,
+			}
+		}
+	}
+
 	return expression
 }
 

parser/parser_test.go

@@ -17,6 +17,8 @@ true; false;
 if(true) {} else if(true) {}else if(true) {} else {};
 1000;
 i = 100
+
+test[0] = 20
 `
 
 	l := lexer.Create(input)
@@ -31,7 +33,7 @@ i = 100
 		log.Fatalln("Errors! ^")
 	}
 
-	if len(program.Statements) != 8 {
+	if len(program.Statements) != 9 {
 		t.Fatalf("len(program.Statements) is not correct. expected=%d. got=%d", 7, len(program.Statements))
 	}
 }