poka.sh

 Docs

PROLOG

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.

Prolog Preview.

At a glance
Purpose Prolog source code: facts, rules and directives of a logic program.
Extensions .prolog
Poka parser poka-prolog
Viewer poka-metadata-card-viewer
Depth tier Metadata card (see Depth tiers)
Breadth tier B4 Summary (see Breadth tiers)

How much Poka reads

B4 Summary. The container and metadata are read and summarised (counts, properties, structure), but the main content is not rendered.

Confidence: medium (the reviewer read the code). Basis: Reviewed 2026-10-26: read parsers/poka-prolog/src/main.rs (283 lines) and plugin.json in full. The crate has no unit tests and no tests/samples.rs, and the corpus has no .prolog sample, so the tier rests on reading the code. Covers .prolog. The output is a metadata card of counts found by matching text line by line: the module declaration, facts, rules, DCG rules, directives, queries, use_module imports, dynamic, discontiguous and multifile declarations, op/3 declarations, distinct predicate names with samples, and line counts. Judgement: B4, because the structure is summarised but the source itself is never shown.

What Poka does not read

  • The source text is not shown: the card carries only counts and a few sample names, with no code view or highlighting
  • Constructs are found by matching text line by line, not by parsing, so multi-line declarations, nested or indented definitions and keywords inside strings or comments can be miscounted
  • Counts of named items stop where their name list is capped (predicate names at 256), so a larger file under-reports them
  • Files over 64 MiB are cut to the first 64 MiB (the card says so)
  • Text that is not UTF-8 is decoded with replacement characters; no other encoding is tried
  • Predicates are named without their arity
  • The module comment names .pl and .pro, which go to poka-code instead (only .prolog reaches this module)

Libraries

Libraries Poka uses or has assessed for this format, with the status, licence and language the registry records.

  • java-prolog-parser (candidate; Apache-2.0; Java; https://github.com/raydac/java-prolog-parser) — Pure Java Edinburgh-style parser with operators and comments; on Maven Central.
  • arena-terms-parser (candidate; MIT; Rust; https://github.com/ikhomyakov/arena-terms) — Parses Prolog-like terms with user operators; README says MIT, a search snippet said LGPL, so check; coverage may be partial.
  • Tau Prolog (candidate; BSD-3-Clause; JavaScript; https://github.com/arcanis/tau-prolog) — ISO Prolog interpreter that parses source in browser or Node; page loaded is a fork of tau-prolog/tau-prolog.
  • Scryer Prolog (candidate; BSD-3-Clause; Rust; https://github.com/mthom/scryer-prolog) — Full Prolog system; README says it passes syntactic conformity tests, but no standalone reader API was confirmed.

Sources

  • parsers/poka-prolog/src/main.rs
  • parsers/poka-prolog/plugin.json