GML Formatter — Allman & K&R

Format your GameMaker Language code properly. No more mess.

by GanjaViruss & Claude Opus 4.8 & Sonnet 4.6

🔗 Manual Formatter Live

🔗 GML Auto Formatter Live

Part of GML Tools

Paste your messy GML code → get clean, readable code back.

• Brace style — Allman (braces on their own line) or K&R (braces on same line), your pick
• Keyword operators — and → &&, or → ||, not → !, mod → %, xor → ^^, <> → !=
• Condition fixer — wraps bare if x > 0 { into if (x > 0) {, fixes = → == inside conditions
• Variable cleanup — removes duplicate var declarations in the same scope (fixes GM2044 "local variable already declared")
• Comment stripping — optionally remove // comments (keeps /// JSDoc) and /* */ block comments
• Proper indentation — configurable (default 4 spaces)
• Inline comments preserved — x = 1; // comment stays on one line
• Switch/case formatting — correct indentation for case bodies
• Template strings safe — $"text {var}" never broken
• Missing semicolons — handles GML code without ; (auto-detects statement boundaries)
• Drag & drop — drop a .gml file onto the page to load it
• Auto-format on paste — paste code and it formats instantly
• Remembers settings — language, brace style and options persist between visits
• Live stats — shows how many operators, conditions, var duplicates and comments were fixed
• Mobile friendly — responsive layout
• Idempotent — format twice, get the same result

Manual Formatter Just open index.html in any browser. No install, no server.

1. Paste GML code on the left.
2. Click FORMAT (or Ctrl+Enter)
3. Copy the clean code from the right.

You can also drag & drop a .gml file onto the page, or paste code and it formats automatically.

GML Auto Formatter

WARRING!!! ⚠️ This overwrites your .gml files in place. Make a backup or commit to git first. Scan the folder, review the count, then format. Closing GameMaker before running is recommended.

1. Open batch.html in Opera/Chrome/Edge browser. No install, no server.
2. Choose MAIN project folder (where is project_name.yyp file)
3. Click Scan and next Format & Save (in place)
4. Wait a while :P
5. DONE!

Before:

if work_data == undefined exit;
if !work_available and not work_paused and regen_timer > 0 {
regen_timer--;
if regen_timer<=0{
work_available=true;
sprite_index=work_data.sprite_idle;
}
}

After:

if (work_data == undefined) exit;
if (!work_available && !work_paused && regen_timer > 0)
{
    regen_timer--;
    if (regen_timer <= 0)
    {
        work_available = true;
        sprite_index = work_data.sprite_idle;
    }
}

• if / else if / else
• while / do..until / repeat
• for loops
• switch / case / default
• with
• function declarations and expressions
• Template strings $"..." and verbatim strings @"..."
• Hex literals $FF
• GML accessors [? ] [# ] [| ] [@ ]
• #macro / #region / #endregion
• Inline and block comments
• Ternary ? :
• Struct literals { key: value }

Bare single-line if without braces (if x > 5 exit;) — the formatter won't add parens here because it can't safely detect where the condition ends and the body begins. Add braces or parens manually for these.

This tool was built with Claude (Opus 4.8 & Sonnet 4.6). I use GML myself, there was no solid formatter for it, people kept asking for one, so I built it and released it as free open source. The engine is a custom tokenizer and pretty-printer written specifically for GML — not a generic JS beautifier hacked with regexes.

v1.5

• Handles GML without semicolons (auto statement-boundary detection) — fixes glued statements/structs
• Batch formatter: format an entire project folder in one click (batch.html)
• Fixed edge case with toString / constructor as variable names

v1.4

• Optional comment stripping: // (keeps /// JSDoc docs) and /* */ block comments

v1.3

• Live stats: operators / conditions / var fixes / comments removed counter
• Responsive layout for mobile
• Bigger built-in example

v1.2

• Brace style choice: Allman / K&R
• Drag & drop file loading
• Auto-format on paste
• Settings persist between visits

v1.1

• Duplicate var cleanup (fixes GM2044 errors)
• Download button to export as .gml
• English default UI

v1.0

• Initial release: Allman formatting, operator conversion, condition fixing

MIT — do whatever you want with it.