I'm using the PHP HereDoc and NowDoc statements to build the web-pages in my web-site, with HereDocs for parts that need PHP variable values substituted into the web-pages, and NowDocs for parts that use the $ characters to specify jQuery statements and jQuery Objects variables in my JavaScript. However, this makes my HTML, CSS, and JavaScript/jQuery hard to read and maintain.
To get around this I thought I'd write a replacement function to perform the PHP variable substitution that HereDoc statements do, but for variables who's values were assigned with string expressions or by NowDoc statements. This way the PHP variables specified by ${variable-name} within the string would be substituted with their values and the jQuery statements and $ prefixed variables who's values are expected to be jQuery Objects are not substituted for PHP variables, what otherwise generally cause a PHP compiler error when there isn't a PHP variable with the name matching the jQuery statement or variable name or a runtime logic error when there is a name match.
Here is my code and a test NowDoc that:
However, when I run the following code to build my web-page, the $test PHP variable isn't visible inside of the function and a NULL is substituted instead of the desired value.
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.0/jquery.min.js"></script>
<?php
//
// PHP
//
function NowHereDoc( &$_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( $strMAINs );
?>
<!-- HTML -->
<b>Test of my PHP NowHereDoc function</b>How can I access PHP variables by their names specified as string values, which are global or local within a function calling the NowHereDoc function from within it without having to pass them in as parameters or specify them as globals variables in the function? I remember seeing a PHP library function that could return a value given its name as a string, but I don't remember the function's name.
Thanks
While not a template solution, which may come later, I found the get_defined_vars() function, that was the piece I remembered seeing, but couldn't remember its name. It gets a list of the defined variables that are in-scope at the time it is called. Alternatively, a manual list of variables could be created and passed into the function, since most of the variables in the defined variables list returned by the get_define_vars() functions are not needed.
function NowHereDoc( &$_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 );
Again, thanks for the help, Matt and CBroe.