Formatting

Nymph has one canonical source style. Formatter integrations use the reusable nymph-format library and produce the same result independently of the filesystem, editor, or command-line environment.

Layout

• Indentation is tabs. A tab has display width 2; spaces are used only for alignment.
• Lines have a soft width of 100 columns.
• Output uses LF line endings and ends with exactly one newline.
• Nonempty blocks and match expressions are multiline.
• A comma-separated list which becomes multiline has one item on each line and a trailing comma.
• Semicolons are not emitted. Imports remain in source order.
• Blank-line runs collapse to one blank line; formatting does not invent declaration groups.

Source preservation

Comments stay in source order. Literal spelling, escapes, numeric bases and separators, and all other non-trivia lexemes are preserved. String interpolations are formatted as expressions, including interpolations containing balanced blocks and match expressions.

The formatter removes only grouping or single-expression block boundaries that are provably redundant. It retains boundaries required by precedence, control flow, guards, closures, labels, or ambiguous comment attachment.

Malformed source is never rewritten: lexer and parser diagnostics are returned as structured data and no output is produced. Range formatting expands a request to a supported syntax unit and returns both that exact replacement span and its text.