"@toon-format/cli" command-line tool

npx @toon-format/cli input.json -o output.toon

Formal syntax highlights (from the official spec & reference implementation) (4/4)

📝Optional “key folding” (v1.5+) collapses chains like data.metadata.items into a single dotted path to save indentation.

Formal syntax highlights (from the official spec & reference implementation) (3/4)

📝Keys are unquoted unless they contain special characters.
📝Empty object → nothing on that line (or explicit empty object is just a blank indented line in some cases).

Formal syntax highlights (from the official spec & reference implementation) (2/4)

📝Strings are quoted only if they contain the delimiter, colon, newline, etc.
📝Empty array → [0]:
📝Supported delimiters: comma (default), tab, or pipe (|) — tab/pipe can sometimes save an extra token or two.

Formal syntax highlights (from the official spec & reference implementation) (1/4)

📝Objects are indented (2 or 4 spaces, configurable), no braces.
📝Arrays of objects → [length]{field1,field2,…}: header, then one object per line.
📝Simple arrays → just list values on the same line or one per line.

In the case of JSON for same data

```
{
"users": [
{ "id": 1, "name": "Alice", "role": "admin" },
{ "id": 2, "name": "Bob", "role": "user" }
]
}
```

≈ 45–50 tokens

Simple example of TOON

```
users[2]{id,name,role}:
1,Alice,admin
2,Bob,user
```

≈ 26–28 tokens

Core ideas behind TOON (2/2)
✅Quote strings only when strictly necessary.
✅Keep the whole thing completely reversible to/from normal JSON.

Core ideas behind TOON (1/2)
✅Use YAML-style indentation for nested objects (no curly braces).
✅Use CSV-style tabular rows for uniform arrays of objects (declare fields once).
✅Add explicit array lengths ([3]) so the model can immediately validate structure.

As a professional in my field, I am tasked with promoting specification-driven development. At the same time, as an individual engineer, I am currently pursuing the question of where the aesthetics lie within that very spec-driven development.

With the rise of AI, I feel we may in a sense be stripped of its artistic quality. Specification-driven development is also gaining prominence. Is there any aesthetics in that? Can specifications possess artistic merit?

In truth, even before its emergence, the direction and design content were more important than writing the code itself. However, there was an aesthetic to code implementation. I believe it was something akin to art.

Frontend: Plain JSP + Struts Tags + jQuery
↓
MVC Layer: Apache Struts 1.3.10
↓
Data Layer: Hibernate 3.6.x (ORM)
↓
Database: MySQL 5.7

The reason for developing is that, to host a workshop on legacy modernization, I have to work hard to build the legacy application.