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Changelog

Source: NEWS.md

arl 0.1.4

CRAN release: 2026-03-19

Performance

  • Reduce CRAN test runtime via uniform test thinning: on CRAN, run every 3rd test block per file (controlled by make_cran_thinner(keep_every = 3L)), cutting ~67% of per-test work while keeping full coverage off CRAN.
  • Reduce TCO test recursion depth on CRAN (6000 vs 10000) to further cut runtime while still validating tail-call optimization well beyond R’s default stack limit.

arl 0.1.3

CRAN Compliance

  • Remove “for R” from package title per CRAN policy.
  • Replace bare cat() calls with S3 print methods (arl_cli_output, arl_help_doc, arl_coverage_report) so console output follows CRAN guidelines.
  • Require explicit output_file argument in report_html() and report_json() — no longer write to the working directory by default.
  • Convert example vignette code chunks from {r} read-and-cat wrappers to arl chunks that execute via the knitr engine.

arl 0.1.2

Performance

  • Pre-build vignettes in the tarball using the .Rmd.orig + stub pattern, cutting ~110s from R CMD check vignette rebuild time.
  • Speed up test suite by avoiding stdlib prelude loading in tests that don’t need it.
  • Reduce TCO test recursion depth to reduce runtime while still checking deeper recursion than R’s defaults allow.

Bug Fixes

  • Fix multiple temporary file and connection leaks uncovered by stricter CRAN-like checking.
  • make install now ships pre-built vignettes (previously installed without them).

Infrastructure

  • make check now mirrors CRAN settings more closely and prints wall-clock time for the R CMD check step.
  • CI fetches gh-pages branch so benchmark data is available during vignette rendering.

arl 0.1.1

Bug Fixes

  • Fixed stale module cache poisoning when ambient macros differ between sessions. The module cache now computes a fingerprint of all macros visible in a module’s parent environment chain (not just the prelude) and invalidates entries when macros change.
  • Fixed missing dependency declaration in looping.arl.
  • Fixed Windows backslash path handling in tests.
  • Fixed FileDeps tests to work during R CMD check.
  • Fixed bad URLs in README and vignettes.
  • Included vignette files in built tarballs (.Rbuildignore fix).

Testing

  • Tests now disallow unexpected/unhandled warnings.
  • Added make coverage-test-file target for single-file coverage testing.

arl 0.1.0

Initial release of arl, a Scheme-inspired Lisp dialect embedded in R.

Language

  • Special forms: quote, if, define, set!, lambda, begin, defmacro, quasiquote/unquote/unquote-splicing, and, or, while, delay, import, and module.
  • Truthiness: #f, #nil, and 0 are falsy; everything else is truthy.
  • Cons cells: First-class dotted pairs, with both cons-cell and R-native list representations.
  • Destructuring: Pattern destructuring in define, set!, let, and lambda, including nested patterns, rest parameters, and defaults.
  • Multiple values: values and call-with-values.
  • Continuations: call-cc via R’s native callCC.

Macro System

  • Compile-time code transformation with quasiquotation templates.
  • Hygiene via gensym and capture.
  • Introspection with macro?, macroexpand, macroexpand-1, and macroexpand-all.
  • Documentation attachment via ;;' comments.

Module System

  • Named and anonymous modules with explicit or export-all exports.
  • Qualified access via / syntax (e.g. math/inc).
  • Import modifiers: :refer, :as, :rename, :reload.
  • Modules are first-class environment objects with locked bindings.
  • Re-export support, circular dependency detection, and module caching.
  • Introspection: module?, module-name, module-exports, module-ref.

Compiler

  • Single-pass compilation from Arl to R expressions.
  • Self-tail-call optimization: rewrites self-recursive functions in tail position as while loops.
  • Constant folding, dead code elimination, strength reduction, identity lambda elimination, boolean flattening, and arithmetic infix compilation.

Standard Library

22 modules (~800 definitions) auto-loaded via a prelude:

  • Core and logic: when, unless, cond, error handling, identity.
  • Types and equality: Full suite of type predicates; equal?, eqv?, eq?.
  • List and sequences: append, reverse, take, drop, nth, range, repeat, cycle, zip, and more.
  • Functional: map, filter, reduce, fold, compose, partial, juxt, complement, constantly.
  • Control flow: try-catch, finally, condition signaling and handling.
  • Binding forms: let, let*, letrec with destructuring.
  • Threading macros: ->, ->>, as->, some->, some->>, cond->, cond->>.
  • Looping: until, do-list, Clojure-style loop/recur.
  • Math: inc, dec, abs, sqrt, trigonometric functions, and more.
  • Strings: str, string-concat, string-split, and friends.
  • I/O: File reading/writing, display, and formatting.
  • Data structures: Hash-backed dict and set types with full operation suites; defstruct macro for S3-backed record types.
  • Sorting: list-sort, sort-by, merge-sorted, stable-sort.
  • Assertions: assert-equal, assert-true, assert-false, and others.

R Interoperability

  • Direct access to all R base and default-package functions.
  • Keyword arguments (:name value), formulas, $, [, [[, and @.
  • r-eval and r-call for dynamic R evaluation.
  • Bidirectional data exchange: define R objects into Arl, extract results back to R.
  • Configurable R package visibility.

Developer Tools

  • REPL: Interactive prompt with multi-line input, readline history, bracketed paste, and error recovery.
  • CLI: Script execution, --eval expressions, quiet mode, bare engine mode, and stdin support.
  • Help system: (help topic) dispatches to special forms, builtins, stdlib docstrings, or R help. doc and doc! for programmatic access.
  • Coverage tracking: Line-level and branch-level instrumentation with console, HTML, and JSON reports.
  • Knitr engine: arl code chunks in R Markdown with persistent engine state and syntax highlighting.

Documentation

  • Vignettes: getting started, standard library reference, compiler and internals, and troubleshooting.