CAPNP
Generated by scripts/gen-format-pages.py from docs/data/format-metadata/, FILE_FORMATS.csv and docs/formats-master.csv. Do not edit by hand: change the source, then run the script.
Cap'n Proto Schema Preview.
At a glance
| Purpose | A Cap'n Proto schema: structs, enums, interfaces and constants that define a serialisation and RPC protocol. |
| Extensions | .capnp |
| Poka parser | poka-capnp |
| Viewer | poka-tree-viewer |
| Depth tier | Parser with a shared viewer (see Depth tiers) |
| Breadth tier | B2 Broad (see Breadth tiers) |
How much Poka reads
B2 Broad. The common content of the current and the common older versions is decoded. Some named features or versions are not, and are listed.
Confidence: medium (the reviewer read the code). Basis: Reviewed 2026-10-26: read parsers/poka-capnp/src/main.rs (787 lines, a brace-aware scanner over a copy with comments and string contents masked) and plugin.json. No unit tests or tests/samples.rs; the corpus has capnproto_addressbook.capnp but no test reads it. Covers .capnp. The tree has the file id, counts, structs with fields (ordinal and type), nested unions and groups, enums with values, interfaces with method signatures, constants and the using and import list.
What Poka does not read
- Every string literal is masked before the scan, so import paths and string constant values show as blanks (judgement from the code)
- Field default values are dropped
- Annotation uses ($Foo(...)) on types and fields are not shown; annotation declarations are listed by name only
- Interface superclasses (extends) and generic parameters are dropped from the names
- Files over 32 MiB are cut without a flag; caps of 200 structs, 200 fields per struct and 3,000 nodes
Libraries
Libraries Poka uses or has assessed for this format, with the status, licence and language the registry records.
- capnp (candidate; MIT; Rust; https://github.com/capnproto/capnproto-rust) — Cap'n Proto official
Sources
- parsers/poka-capnp/src/main.rs
- parsers/poka-capnp/plugin.json