Memoize docstring parsing - #1480
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OxCaml's ppx_template-heavy libraries attach the same comment text to
thousands of monomorphised copies (Container_intf in OxCaml's base:
~155K comments, 33 unique). Cache parse results keyed on the text —
but only parses that produced no warnings and contain no
location-sensitive constructs (headings, references, {!modules ...}),
since the AST bakes in absolute locations from the first occurrence.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
comment_docs rebuilt every docs element even though linking only
changes references, headings and {!modules ...} lists. Return the
input unchanged when none are present.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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OxCaml's libraries tend to have a lot of repeated comments due to ppx_template. This PR memoizes the parsing and skips resolving if they don't need it. On
Container_intfinbase:Impact (on
odoc_driver core):.odocfiles −18%,.odoclfiles −23% on disk: memoized doc ASTs are physically shared, and Marshal serialises shared structure once. This compounds downstream (less unmarshalling, less memory).On stock OCaml, there's no cpu usage change, but we do save some space in the odoc and odocl files (~4%).