变量之间的操作（Operations between Variables）¶

我们几乎可以做任何类型的两个变量之间的进行操作，当我们不知道确切的数据类型时，我们也可以使用 Zend API 操作它们。

  1. // First variable is string but it's a numeric string
  2. ZVAL_STRING(&first_var, "100.10");
  3.  
  4. // Second variable is long
  5. ZVAL_LONG(&second_var, 150);
  6.  
  7. // add_function will make the necessary conversions to produce the addition
  8. add_function(&result, &first_var, &second_var);

连接（Concatenation）¶

在 PHP 中连接操作是最频繁的操作之一，我一样可以使用 Zend API 简单实现多个值的拼接：

  1. // The following concatention using just Zend API:
  2. //
  3. // $month = "July"; $day = 1;
  4. // $today = "Today is ".$month." ".$day;
  5.  
  6. ZVAL_STRING(&month, "2012");
  7.  
  8. ZVAL_LONG(&day, 1);
  9.  
  10. ZVAL_STRING(&today_is, "Today is");
  11.  
  12. concat_function(&first_part, &today_is, &month);
  13.  
  14. ZVAL_STRING(&space, " ");
  15.  
  16. concat_function(&second_part, &space, &day);
  17.  
  18. concat_function(&today, &first_part, &second_part);

Another way to do that is use sprintf, in this case, you need to be completely sure that the variables have all string types:

  1. char *final_string;
  2. zval final;
  3.  
  4. ZVAL_STRING(&month, "2012");
  5.  
  6. ZVAL_STRING(&day, "1");
  7.  
  8. final_string = emalloc(sizeof(char)*(Z_STRLEN_P(month)+Z_STRLEN_P(day)+12)));
  9. sprintf(final_string, "Today is %s %s", Z_STRVAL_P(month), Z_STRVAL_P(day));
  10.  
  11. ZVAL_STRING(&final, final_string);

常用函数列表¶

Phalcon API 在 Zend API 的基础上提供更多的函数和弘定义（kernel/operators.h）。

函数名/宏名
phalcon_compare
phalcon_is_equal
phalcon_less
phalcon_greater
phalcon_is_scalar
phalcon_get_intval

It’s short, but if some of your variables aren’t string you will get a segmentation fault or an unexpected behavior.

To help to solve this problem, we have created a set of macros to concatenate zvals and strings:

  1. ZVAL_STRING(&month, "2012", 1);
  2.  
  3. ZVAL_STRING(&day, "1", 1);
  4.  
  5. PHALCON_CONCAT_SVSV(&today, "Today is", &month, " ", &day);

Other examples:

  1. PHALCON_CONCAT_VV(&result, &month, &day); //July1
  2. PHALCON_CONCAT_VSV(&result, &month, ", ", &day); //July, 1
  3. PHALCON_CONCAT_SVSV(&result, "Today is", &month, " ", &day); //July 1
  4. PHALCON_CONCAT_SVSVSV(&result, "Today is", &month, " ", &day, ", ", &year); //July 1, 2012

S=String and V=Zval, just put the S and V to get the right concatenation macro. Easy, no?

原文: http://www.myleftstudio.com/internals/operations.html