Function ExprEvalPushStep

src/backend/executor/execExpr.c:2521–2537

* Add another expression evaluation step to ExprState->steps. * * Note that this potentially re-allocates es->steps, therefore no pointer * into that array may be used while the expression is still being built. */

 * into that array may be used while the expression is still being built.
 */
void
ExprEvalPushStep(ExprState *es, const ExprEvalStep *s)
{
	if (es->steps_alloc == 0)
	{
		es->steps_alloc = 16;
		es->steps = palloc(sizeof(ExprEvalStep) * es->steps_alloc);
	}
	else if (es->steps_alloc == es->steps_len)
	{
		es->steps_alloc *= 2;
		es->steps = repalloc(es->steps,
							 sizeof(ExprEvalStep) * es->steps_alloc);
	}

	memcpy(&es->steps[es->steps_len++], s, sizeof(ExprEvalStep));
}

/*
 * Perform setup necessary for the evaluation of a function-like expression,