yeslogic / fathom

🚧 (Alpha stage software) A declarative data definition language for formally specifying binary data formats. 🚧

Apache License 2.0

258 stars 14 forks source link

Rewrite pretty printer #477

Closed Kmeakin closed 1 year ago

Kmeakin commented 1 year ago

Rewrote the surface pretty printer using the algorithm from A New Language-Independent Prettyprinting Algorithm. The resulting code is a little imperative compared to the old functional style, but I think it should be possible to write a functional wrapper around the imperative algorithm.

TODO:

Tweak heuristics to match the old pretty printing output
Avoid emitting trailing whitespace at the end of lines

Kmeakin commented 1 year ago

Benchmark results

Peak heap usage, as measured by heaptrack ./target/release/fathom data --module formats/opentype.fathom /usr/share/fonts/liberation/LiberationMono-Bold.ttf
- main: 142.9MB
- new-pretty: 10.4MB
Runtime, as measured by hyperfine -w 1 -r 10 "./target/release/fathom data --module formats/opentype.fathom /usr/share/fonts/liberation/LiberationMono-Bold.ttf":
- main: 328.9 ms ± 4.0 ms
- new-pretty: 24.0 ms ± 0.5 ms

Kmeakin commented 1 year ago

Abandoned in favour of https://github.com/yeslogic/fathom/pull/483