Expand Gotlin language and tooling

internal/lang/foreach.go

@@ -0,0 +1,28 @@
+package lang
+
+import "fmt"
+
+func (p *parser) parseForEach() (Stmt, error) {
+	if _, err := p.expect(tokenLParen, "expected '(' after 'for'"); err != nil {
+		return nil, err
+	}
+	name, err := p.expect(tokenIdent, "expected iteration variable")
+	if err != nil {
+		return nil, err
+	}
+	if _, err := p.expect(tokenIn, "expected 'in' after iteration variable"); err != nil {
+		return nil, err
+	}
+	source, err := p.parseExpr(0)
+	if err != nil {
+		return nil, err
+	}
+	if _, err := p.expect(tokenRParen, "expected ')' after iteration source"); err != nil {
+		return nil, err
+	}
+	body, err := p.parseBlock()
+	if err != nil {
+		return nil, fmt.Errorf("invalid for body: %w", err)
+	}
+	return ForEachStmt{Name: name.lexeme, Source: source, Body: body}, nil
+}