skip tokens in output

README.md

@@ -1,7 +1,7 @@
 # tin
 
-tin is a PHP code highlighter for the terminal. 
- 
+tin is a PHP code highlighter for the terminal.
+
 [![Tests](https://github.com/felixdorn/tin/actions/workflows/tests.yml/badge.svg?branch=main)](https://github.com/felixdorn/tin/actions/workflows/tests.yml)
 [![Formats](https://github.com/felixdorn/tin/actions/workflows/formats.yml/badge.svg?branch=main)](https://github.com/felixdorn/tin/actions/workflows/formats.yml)
 [![Version](https://poser.pugx.org/felixdorn/tin/version)](//packagist.org/packages/felixdorn/tin)
@@ -47,11 +47,21 @@ use Felix\Tin\Token;
 
 $tin->process(
     $code,
-    fn(Token $token, Token $lastToken) => $token->line . '| ' . $token->text
+    function(Token $token, Token $lastToken): ?string  {
+        // won't print any of the ";" tokens
+        if ($token->is(";")) {
+           return null;
+        }
+
+        return $token->line . '| ' . $token->text;
+    }
 )
 ```
 
-> Last token represents the last token in the input code, it is very useful as you can then get the number of lines in the code with `$lastToken->line` to properly indent line numbers for example.  
+Last token represents the last token in the input code, it is very useful as you can then get the number of lines in the
+code with `$lastToken->line` to properly indent line numbers for example.
+
+If you return `null` from the callback, the token will be skipped.
 
 ## Themes
 
@@ -87,6 +97,7 @@ class OneDark extends Theme
 * Various outputs (cli / web)
 * grayscale theme
 * better themes (will also boost performances a lot!!)
+
 ## Known Issues
 
 Named parameters are simply ignored by the built-in PHP parser which means that if you're named parameter is also a

src/Tin.php

@@ -61,9 +61,14 @@ public function process(string $code, callable $transformer): string
                 };
             }
 
-            $text        = $token->text;
-            $token->text = "\e[38;2;" . $color . 'm' . $token->text . "\e[0m";
-            $highlighted .= $transformer($token, $lastToken);
+            $text             = $token->text;
+            $token->text      = "\e[38;2;" . $color . 'm' . $token->text . "\e[0m";
+            $highlightedToken = $transformer($token, $lastToken);
+
+            if ($highlightedToken !== null) {
+                $highlighted .= $highlightedToken;
+            }
+
             $token->text = $text;
         }
 

tests/TinTest.php

@@ -27,3 +27,17 @@
 
     expect($output)->toBe(T_OPEN_TAG . T_ECHO . T_WHITESPACE . T_CONSTANT_ENCAPSED_STRING . ord(';'));
 });
+
+it('can skip tokens', function () {
+    $tin = Tin::from(new OneDark());
+
+    $output = $tin->process('<?php echo "Hello world";', function (Token $token, Token $lastToken) {
+        if ($token->id === T_ECHO) {
+            return null;
+        }
+
+        return $token->id;
+    });
+
+    expect($output)->toBe(T_OPEN_TAG . T_WHITESPACE . T_CONSTANT_ENCAPSED_STRING . ord(';'));
+});