22.5. Source HighlightingAn easy way to spot very basic errors is to use a text editor that has syntax highlighting capabilities. Editors like these will recognize that you are editing a PHP script and automatically highlight the text in such a way as to make each element stand out in the source code. We discussed syntax highlighting earlier, but what I want to mention here is that PHP has built-in support for syntax highlighting itself. The two key functions here are highlight_file( ) and highlight_string( ), although there is also a function show_source( ) that is an alias to highlight_file( ). This takes a filename as its parameter and outputs that file to the screen, with all keywords, strings, numbers, and functions highlighted in various colors, as shown in Figure 22-1. The highlight_string( ) function is almost identical, except it takes a string as its parameter.
Figure 22-1. PHP has its own syntax highlighting system that provides a little help for debugging, but is still no replacement for full syntax highlightingThis example shows how to highlight a string of code and also a file: $mystr = '<?php $foo = "bar"; $bar = array("baz", "wombat", "foo"); var_dump($foo); ?>'; highlight_string($mystr); file_put_contents("highlighter.php", $mystr); highlight_file("highlighter.php"); As you can see, that passes the string into highlight_string( ), then saves it out as highlighter.php and passes that filename into highlight_file( ) to print out again. Both highlight_string( ) and highlight_file( ) can take a second parameter, which, if set to true, will make these functions return the highlighted HTML rather than just print it out directly, giving you more control over it. |