public void specExecSql(HplsqlParser.Expr_spec_funcContext ctx) {
    String name = ctx.start.getText().toUpperCase();
    if (trace && ctx.parent.parent instanceof HplsqlParser.Expr_stmtContext) {
      trace(ctx, "FUNC " + name);
    }
    FuncSpecCommand func = specSqlMap.get(name);
    if (func != null) {
      func.run(ctx);
    }
    else {
      specExec(ctx);
    }
  }
Execute a special function in executable SQL statement
hplsql/src/main/java/org/apache/hive/hplsql/functions/BuiltinFunctions.java