format

Overview ¶

Package format renders an ast.File back to canonical CraftGo source.

The printer is round-trip safe for every well-formed input: parsing the printer's output produces an AST equal to its input, and a second formatting pass is a no-op (idempotency).

Comment recovery is driven entirely from `f.Comments` - the parser snapshots every `//` comment (with position and leading/trailing kind) from the lexer onto that slice. The printer derives its trailing / loose lookup maps from the slice via [buildTrailingFromComments] and [buildLooseFromComments]; no source-bytes scan is needed. As a result Format (which has the source) and Print (AST only) produce the same output - both rely on the same `f.Comments` data.

Two entry points are provided:

• Format takes a source buffer, parses it, and returns formatted text plus any diagnostics. Suitable for `craftgo fmt` and editor integration.
• Print takes an ast.File and writes formatted text to an io.Writer. Suitable for callers that already have an AST in hand. Comment recovery works as long as the file's `Comments` slice was populated (which the parser always does).

Output conventions:

• Tabs for indentation (Go-ecosystem convention; editors render the visual width via their own settings).
• Field rows inside a type body are column-aligned by name and type so decorator chains line up.
• The `request` / `response` lines inside a method body share a two-space alignment so the type column matches.

Comment recovery: trailing / loose / free-comment span derivation from f.Comments.

Per-declaration print methods + type-ref rendering.

Decorator + expression printing for decorator argument trees.