[英]Why can't my local PHP function see the $test variable, and how can I get its value?
我正在使用 PHP HereDoc 和 NowDoc 语句在我的网站中构建网页,HereDocs 用于需要将 PHP 变量值替换到网页中的部分,NowDocs 用于使用$字符指定 jQuery 的部分我的 JavaScript 中的语句和 jQuery 对象变量。 然而,这使得我的 HTML、CSS 和 JavaScript/jQuery 难以阅读和维护。
为了解决这个问题,我想我会写一个替换函数来执行 HereDoc 语句所做的 PHP 变量替换,但是对于用字符串表达式或 NowDoc 语句分配值的变量。 这样,字符串中${ variable-name }指定的 PHP 变量将被替换为它们的值,并且 jQuery 语句和$前缀变量的值应该是 jQuery 对象不会替换 PHP 变量,否则通常会导致如果没有名称与 jQuery 语句或变量名称匹配的 PHP 变量,则会出现 PHP 编译器错误,或者在名称匹配时出现运行时逻辑错误。
这是我的代码和一个测试 NowDoc:
但是,当我运行以下代码来构建我的网页时,$test PHP 变量在函数内部不可见,并且替换为 NULL 而不是所需的值。
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.0/jquery.min.js"></script> <?php // // PHP // function NowHereDoc( &$_array_ ) { // By Ref array parameter minimizes data movement when calling this function. $_l_ = count( $_array_ ); $_s_ = $_array_[ $_l_ - 1 ]; // Get the last element's string value. // Find each ${...} and substitute the variable's value ... $_i1_ = 0; while( ( $_i1_ = strpos( $_s_, '${', $_i1_ ) ) !== FALSE ) { // Get index of start of a variable name specified // by ${...} or FALSE when there aren't any {more}, // then stop looping. $_i2_ = strpos( $_s_, '}', $_i1_ ); // Get index of end of the ${...} just found. $_l_ = $_i2_ - $_i1_ + 1; // Get length of ${...}. $_var_ = substr( $_s_, $_i1_, $_l_ ); // Get the variable's name as a string. $_v_ = str_replace( [ '{', '}' ], '', $_var_ ); // Remove { and } from the variable name. $_val_ = "$_v_"; // Get the value of the specified variable -- this // doesn't find the variable, instead returns NULL! // Substitute the variable's value into the original string, $_s_ // $_s_ = substr_replace( $_s_, $$_var_, $_i1_, $_l_ ); // Replace the single occurance of the variable // with its value. This could to replace occurances // not with in comments, not yet implemented in // function. $_s_ = str_replace( $_var_, $_val_, $_s_ ); // Replace all occurances of the variable with its // value. } // End of while( ( $_i1_ = strpos( $_s_, '${', $_i1_ ) ) !== FALSE ) ... $_array_[ $_l_ - 1 ] = $_s_; // Set the last element's string value to the // updated string in $_s_. } // No Variable substitutions allowed in a NowDoc. $strMAINs[] = <<<'MAIN' <!-- ====================================================== ====================================================== = = HTML - ${test} - This should be substituted with hi = ====================================================== ====================================================== --> <p>to be set by this following script</p> <script id="scriptId"> // // JavaScript! // // The following jQuery statement shouldn't be changed. // var $jQVar = $( 'p' ).html( 'there' ); </script> MAIN; // // PHP // $test = 'hi'; NowHereDoc( $strMAINs ); ?> <!-- HTML --> <b>Test of my PHP NowHereDoc function</b>
如何通过指定为字符串值的名称访问 PHP 变量,这些变量在调用 NowHereDoc 函数的函数中是全局的或局部的,而不必将它们作为参数传入或在函数中将它们指定为全局变量? 我记得看到一个 PHP 库函数可以返回一个给定其名称作为字符串的值,但我不记得该函数的名称。
谢谢
要将全局变量导入您的函数,您可以执行以下操作:
// global scope
$test = 'my string';
function myFunction() {
global $test;
}
或者,如果您有一个匿名函数,您可以像这样从父作用域中提取变量:
function myOuterFn() {
$test = 'my string';
$myInnerFn = function() use ($test) {
echo $test;
};
}
为了回应您的评论,如果您遍历内容以将任何引用的变量提取到一个 var 名称数组中,您可以遍历该数组并从全局导入它们,如本示例所示: https : //3v4l.org/ rH8J0
虽然不是模板解决方案,可能会在以后出现,但我找到了get_defined_vars()函数,这是我记得看到的那部分,但不记得它的名字。 它获取调用时在范围内的已定义变量的列表。 或者,可以创建一个手动变量列表并将其传递给函数,因为get_define_vars()函数返回的已定义变量列表中的大多数变量都是不需要的。
function NowHereDoc( &$_vars_, &$_array_ ) { // a by-ref array of variables and their values from the caller's scope.
//
// a by-ref array specifying the web-content as a string that
// contains one or more PHP variables in the ${...} format who's
// values are to be substituted for the variable name.
//
// & By-Ref prefix minimizes data movement when calling this function.
//
$_l_ = count( $_array_ );
$_s_ = $_array_[ $_l_ - 1 ]; // Get the last element's string value.
// Find each ${...} and substitute the variable's value ...
$_i1_ = 0;
while( ( $_i1_ = strpos( $_s_, '${', $_i1_ ) ) !== FALSE ) { // Get index of start of a variable name specified
// by ${...} or FALSE when there aren't any {more},
// then stop looping.
$_i2_ = strpos( $_s_, '}', $_i1_ ); // Get index of end of the ${...} just found.
$_l_ = $_i2_ - $_i1_ + 1; // Get length of ${...}.
$_var_ = substr( $_s_, $_i1_, $_l_ ); // Get the variable's name as a string.
$_v_ = str_replace( [ '$', '{', '}' ], '', $_var_ ); // Remove { and } from the variable name.
$_val_ = $_vars_[ $_v_ ]; // Get the value of the specified variable.
// Substitute the variable's value into the original string, $_s_
// $_s_ = substr_replace( $_s_, $_val_, $_i1_, $_l_ ); // Replace the single occurance of the variable
// with its value. This could to replace occurances
// not with in comments, not yet implemented in
// function.
$_s_ = str_replace( $_var_, $_val_, $_s_ ); // Replace all occurances of the variable with its
// value.
} // End of while( ( $_i1_ = strpos( $_s_, '${', $_i1_ ) ) !== FALSE ) ...
$_array_[ $_l_ - 1 ] = $_s_; // Set the last element's string value to the
// updated string in $_s_.
}
// No variable substitutions.
$strMAINs[] = <<<'MAIN'
<!--
=======================================================================
=======================================================================
=
= ${test1} ${test2} // ${test1} ${test2} should be substituted with hi there
=
=======================================================================
=======================================================================
-->
MAIN;
$test1 = 'hi';
$test2 = 'there';
$vars = get_defined_vars();
NowHereDoc( $vars, $strMAINs );
再次感谢马特和 CBroe 的帮助。
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