Perl Code Formatter

Features

• A real tree-sitter parse — indentation follows the grammar, not bracket counting
• Brackets inside strings, comments and `q{}` do not affect the structure
• Heredoc bodies and POD directives are never touched — a Perl-specific guard
• Only leading whitespace changes; not a character inside a line
• Indent with 2 spaces, 4 spaces or tabs
• Incomplete code still produces output instead of an error
• Syntax-highlighted output
• Runs entirely on your device — the code is never uploaded

How to use

1. Paste the code into the left pane
2. Pick an indent width
3. Press Ctrl/⌘ + Enter or click Run
4. Copy the result

FAQ

How is this different from other online formatters?

Most online formatters do text-level indentation: scan character by character, indent on `{`, dedent on `}`. They cannot tell whether a bracket is in the code or inside a string. This one uses a real parser: the code becomes a syntax tree first, and each line’s depth is decided by the grammar it belongs to. The cost is a Perl grammar file plus the parser runtime (about 4.4 MB together), downloaded only when you open this tool’s page. What you get in return is structure detection that does not guess.

Are heredocs and POD ever changed?

No — and this is a Perl-specific care. A heredoc body and POD directives (such as `=head1`) are left completely alone: a heredoc body is string content, so indenting it inserts spaces into your data, and POD directives must start at column 0 — indent one and Perl stops treating it as POD, parses it as code, and fails with a syntax error. This includes `<<~` heredocs, where Perl strips the common leading whitespace: the relative indentation of the body lines is the meaning, so moving a single line changes the result.

Why did my code come out unchanged?

That usually means it was already correct, which is the best outcome. The worst failure for a formatter is not ugly output but altering correct code — that change lands in a diff and in code review, and it is hard to say who made it. So the strategy here is to act only when there is something to fix. When the code genuinely is misindented, the output does change.

Will it change what my code does?

No. Only the leading whitespace of each line is touched — not one character inside a line, no reordering, no re-wrapping, no line removal, nothing inside strings or comments, and heredoc bodies and POD are kept whole. So even with wildly unusual formatting the worst case is indentation you do not like, while the code still runs. By the same token, it cannot add missing syntax (a dropped bracket, a forgotten semicolon). It is an indentation tool, not a repair tool.