/** String concatenation operator */ public void operatorConcat(HplsqlParser.Expr_concatContext ctx) { StringBuilder val = new StringBuilder(); int cnt = ctx.expr_concat_item().size(); boolean nulls = true; for (int i = 0; i < cnt; i++) { Var c = evalPop(ctx.expr_concat_item(i)); if (!c.isNull()) { val.append(c.toString()); nulls = false; } } if (nulls) { evalNull(); } else { evalString(val); } }