Function evaluateExpr

src/bin/pgbench/pgbench.c:2654–2693

* Recursive evaluation of an expression in a pgbench script * using the current state of variables. * Returns whether the evaluation was ok, * the value itself is returned through the retval pointer. */

 * the value itself is returned through the retval pointer.
 */
static bool
evaluateExpr(CState *st, PgBenchExpr *expr, PgBenchValue *retval)
{
	switch (expr->etype)
	{
		case ENODE_CONSTANT:
			{
				*retval = expr->u.constant;
				return true;
			}

		case ENODE_VARIABLE:
			{
				Variable   *var;

				if ((var = lookupVariable(st, expr->u.variable.varname)) == NULL)
				{
					pg_log_error("undefined variable \"%s\"", expr->u.variable.varname);
					return false;
				}

				if (!makeVariableValue(var))
					return false;

				*retval = var->value;
				return true;
			}

		case ENODE_FUNCTION:
			return evalFunc(st,
							expr->u.function.function,
							expr->u.function.args,
							retval);

		default:
			/* internal error which should never occur */
			pg_log_fatal("unexpected enode type in evaluation: %d", expr->etype);
			exit(1);
	}
}

/*
 * Convert command name to meta-command enum identifier