Changelog

All notable changes to Korrin are recorded here. The format follows Keep a Changelog. Korrin is pre-1.0 and uses 0.MINOR.PATCH; while the major version is 0, any release may contain breaking changes, which are called out under Changed / Removed.

Unreleased

Milestone 2 is complete: string interpolation, methods on the built-in types, exceptions, modules, and the first standard-library modules (math, io). Milestone 1's entries are further below.

Added — Milestone 2

• String interpolation. Every string literal is a template: "hi {name}" splices the str() value of each { expr } hole, evaluated left to right. {{ / }} are literal braces. Holes are full expressions and need no escaping for nested strings ("{m["k"]}"). (ADR 0015, specification §1.7 and §4.2.)

• Methods on str, list, and map. The . operator now works on the built-in types. New vocabulary:

  • str: len, upper, lower, trim, split, replace, find, contains, starts_with, ends_with, slice, repeat.
  • list: len, push, pop, insert, remove_at, index_of, contains, slice, reverse, sort, join.
  • map: len, keys, values, has, get, remove, pairs.

  (ADR 0016, specification §8.2–8.4.)

• Exceptions. raise <value> unwinds until a try: / except [name]: / finally: catches it, or it reaches the top level as E0312. Any value may be raised; Error(message?) is the built-in exception type, with .message and .code. Built-in runtime faults (E0301–E0313) are now catchable — an except binds them as an Error carrying the faulting code. finally runs on every exit path, including return / break / continue. (ADR 0017, specification §5.10–5.11 and §9.6.)

• Keywords try, except, finally, raise (19 → 23). Parser error E0107 for a try with no clause, or a dangling except / finally.

• Modules. import "./util" runs a Korrin file (resolved relative to the importing file, .kor implied) and binds a module object — type() is "module", members are mod.name, top-level _names are private. import "./x" as y renames. Modules load once and are cached; importing the same module twice yields the same object. A circular import is E0315; a module that will not resolve, read, or compile is E0314. import "math" (no ./) loads a built-in module. New korrin::run_file API; korrin run resolves relative imports against the file's directory. (ADR 0018, specification §11.)

• math standard-library module. import "math": sqrt, pow, floor, ceil, round, abs, min, max, and the constants pi and e. (ADR 0019, specification §11.4.)

• io standard-library module. import "io": read_file(path), write_file(path, text), and args() (command-line arguments). Failures raise a catchable E0316. korrin run script.kor a b c passes a b c to io.args(). New Interpreter::set_args. (ADR 0020, specification §11.5.)

• Keywords import, as (23 → 25). Parser error E0108 for a malformed import or a stray as.

Changed — Milestone 2

• Breaking: a literal { in a string must now be written {{. No existing Korrin code, spec example, or guide example was affected.

• Breaking: the collection built-in functions are removed in favour of methods (ADR 0016):

  Removed	Replacement
  len(x)	x.len()
  append(xs, v)	xs.push(v)
  pop(xs)	xs.pop()
  keys(m) / values(m)	m.keys() / m.values()
  has(m, k)	m.has(k)
  get(m, k, default?)	m.get(k, default?)
  remove(m, k)	m.remove(k)

  print, type, str, int, float, bool, range, and input remain functions.

Added — Milestone 1

• Project scaffold: Cargo workspace (korrin library + korrin-cli binary), toolchain pin, CI, lint configuration.

• Documentation backbone: ADR process and the initial decision records (0000–0013), specification and guide skeletons, contributor docs.

• span module: byte-offset Span and Spanned<T>.

• diagnostics module: Diagnostic, ErrorCode, Severity, SourceMap, and ariadne-backed rendering.

• lexer module: full tokenizer with the indentation state machine (INDENT/DEDENT/NEWLINE), bracket-aware and operator-aware newline suppression, all literal forms, and local error recovery. Specification section 01 (lexical structure) written to match.

• ast module: expression and statement node types, all span-carrying, plus an S-expression dump for debugging and tests.

• parser module: recursive-descent statements + Pratt-parsed expressions, non-associative comparisons, error recovery that reports multiple problems. the grammar (specification section 02) and sections 04, 05 written to match.

• resolver module: static validation pass (return/break/continue/super placement, duplicate parameters, self-inheritance).

• interpreter module: tree-walking evaluator — values, environments, the nearest-binding rule, closures, classes with single inheritance and super, checked integer arithmetic, on-demand stack growth with a recursion backstop.

• builtins module: print, len, type, str, int, float, bool, range, input, and the collection functions append, pop, keys, values, has, get, remove. Specification section 08 written to match.

• korrin::run embedding API and Interpreter for REPL use.

• korrin binary: run, tokens, and ast subcommands, plus an interactive REPL with multi-line input and expression echo.

• Runnable example programs under crates/korrin/examples/.

• CI-enforced documentation harnesses: tests/spec.rs executes every runnable example in the specification and the guide, tests/builtins.rs checks builtin/spec agreement both ways, tests/adr.rs checks ADR structure, index completeness, and numbering.

• Golden end-to-end program corpus (tests/programs/), property tests (tests/properties.rs: the front end never panics), and CLI black-box tests.

• The complete specification (sections 01–10) and the learn-by-example guide.

• mdBook skeleton (docs/book.toml, docs/SUMMARY.md) for the eventual site.

• VS Code syntax-highlighting extension (editors/vscode/) and a workspace .vscode/settings.json that falls back to Python highlighting for .kor.

• playground.kor — a runnable scratch file for experimenting.

• branding/ — the Korrin mark, wordmark, favicon, and usage notes.

• korrin-web/ — the website: a static landing page plus the full guide, specification, and design notes rendered from docs/ by mdBook (themed to the Korrin identity). scripts/deploy-site.sh builds and deploys it to Cloudflare Pages.

Changed — Milestone 1

• self is no longer a keyword; it is a conventional identifier (the name of a method's first parameter). The reserved-word count is now 19. See ADR 0006.
• Scoping is function-level, not block-level: a name first assigned inside an if / while / for body stays visible afterwards. See ADR 0011.
• The grammar moved from a standalone korrin.ebnf file into specification §2 — one source, and it renders in the documentation site.