printer: support SubscriptExpr

Author: haya14busa

printer/expr.go

@@ -18,7 +18,11 @@ func (p *printer) expr1(expr ast.Expr, prec1 int) {
 		p.binaryExpr(x, prec1)
 	case *ast.UnaryExpr:
 		p.unaryExpr(x, prec1)
-	// case *ast.SubscriptExpr:
+	case *ast.SubscriptExpr:
+		p.expr1(x.Left, opprec(x))
+		p.token(token.SQOPEN)
+		p.expr(x.Right)
+		p.token(token.SQCLOSE)
 	// case *ast.SliceExpr:
 	// case *ast.CallExpr:
 	// case *ast.DotExpr:

printer/expr_test.go

@@ -27,6 +27,7 @@ func TestFprint_expr(t *testing.T) {
 		{in: `1+(2*3)`, want: `1 + (2 * 3)`},            // ParenExpr
 		{in: `(((x+(1))))`, want: `(x + (1))`},          // ParenExpr
 		{in: `x+1==14 ||-1`, want: `x + 1 == 14 || -1`}, // BinaryExpr
+		{in: `x[ y ]`, want: `x[y]`},                    // SubscriptExpr
 	}
 
 	for _, tt := range tests {