 | Highlighting (Making Code (Look) Beautiful) |  |
There are lots of packages and tool for color highlighting your code - in lots of different languages - you can even write your own. However, did you know that there is a built in string highlighter in PHP? The highligher is simple, fast and very effective - it produces syntax highlighted (HTML) code!
$aa = "<?php
for i = 2;
let b = 2;
b = 2 * 4;
// comment var
' ddd s var a= 2;'
tesr
";
$bb = highlight_string( $aa, true );
echo( $bb );
The above code will produce this output:
<code><span style="color: #000000">
<span style="color: #0000BB"><?php
<br /></span><span style="color: #007700">for </span><span style="color: #0000BB">i </span><span style="color: #007700">= </span><span style="color: #0000BB">2</span><span style="color: #007700">;
<br /></span><span style="color: #0000BB">let b </span><span style="color: #007700">= </span><span style="color: #0000BB">2</span><span style="color: #007700">;
<br /></span><span style="color: #0000BB">b </span><span style="color: #007700">= </span><span style="color: #0000BB">2 </span><span style="color: #007700">* </span><span style="color: #0000BB">4</span><span style="color: #007700">;
<br /></span><span style="color: #FF8000">// comment var
<br />
<br /></span><span style="color: #DD0000">' ddd s var a= 2;'
<br /></span><span style="color: #0000BB">tesr
<br /></span>
</span>
</code>
Just a small warning about the additional argument true - if this isn't set - the output from the highlight_string function will be passed directly to the output instead of being returned as a string.
This is what the colorful code would look like in a browser:
<?php
for i = 2;
let b = 2;
b = 2 * 4;
// comment var
' ddd s var a= 2;'
tesr
| Stripping off the and
Tags | |
We'll assume the string always has this at the start and end - so we can find the offsets and get the substring.
// strip off the '<?php' and
$bb = substr( $bb, strpos($bb, 'php') + 4 + 6 + 7 ); // start php '4' is for 'php' and arrows, 7 is for '<br />', '7' is for the span
$bb = substr( $bb, 0, strrpos($bb, '</span>') ); // end
The above example would change to this with these extra two lines:
<span style="color: #007700">for </span><span style="color: #0000BB">i </span><span style="color: #007700">= </span><span style="color: #0000BB">2</span><span style="color: #007700">;
<br /></span><span style="color: #0000BB">let b </span><span style="color: #007700">= </span><span style="color: #0000BB">2</span><span style="color: #007700">;
<br /></span><span style="color: #0000BB">b </span><span style="color: #007700">= </span><span style="color: #0000BB">2 </span><span style="color: #007700">* </span><span style="color: #0000BB">4</span><span style="color: #007700">;
<br /></span><span style="color: #FF8000">// comment var
<br />
<br /></span><span style="color: #DD0000">' ddd s var a= 2;'
<br /></span><span style="color: #0000BB">tesr
<br /></span>
Of course, the pretty colorful version (what it looks like in the output):
for i = 2;
let b = 2;
b = 2 * 4;
// comment var
' ddd s var a= 2;'
tesr
| Helper Function | |
Taking the notes into consideration we can construct a simple highlight function that takes a string and returns the highlighted code (without the additional code span tags and the php delimiter).
function highlight($code)
{
$bbbcode = "<?php" . $code;
$bbbcolor = highlight_string( $bbbcode, true );
// start php '4' is for 'php' and arrows - no newline - so the 5 is for the span
$bbbcolor = substr( $bbbcolor, strpos($bbbcolor, 'php') + 4 + 6 );
// subtrack - so it removes the span at end
$bbbcolor = substr( $bbbcolor, 0, strrpos($bbbcolor, '</span>') ); // end
return '<div style="background-color:rgba(100,100,250,0.1);min-height:4px;">' . $bbbcolor . '</div>';
}
| Other Resources | |
• Highlighting using Regular Expressions
• Notepad++ (Export Color Highlighting)
• Notebook Example HighlightJS
• JS HighlightJS Library (Free JS Library)
• Prism Highlighter
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