File.copy(source, dest) copies files via interpreter (std::fs::copy) and
C backend (fread/fwrite). Effectful callbacks passed to higher-order
functions like List.map/forEach now propagate their effects to the
enclosing function's inferred effect set.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add Map<String, V> as a first-class built-in type for key-value storage,
needed for self-hosting the compiler (parser/typechecker/interpreter all
rely heavily on hashmaps).
- types.rs: Type::Map(K,V) variant, all match arms (unify, apply, etc.)
- interpreter.rs: Value::Map, 12 BuiltinFn variants (new/set/get/contains/
remove/keys/values/size/isEmpty/fromList/toList/merge), immutable semantics
- typechecker.rs: Map<K,V> resolution in resolve_type
- js_backend.rs: Map as JS Map with emit_map_operation()
- c_backend.rs: LuxMap struct (linear-scan), runtime fns, emit_map_operation()
- main.rs: 12 tests covering all Map operations
- validate.sh: now checks all projects/ directories too
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Resolve type aliases (e.g. Player -> { pos: Vec2, speed: Float })
before checking if spread expression is a record type. Previously
{ ...p, field: val } failed with "must be a record type, got Player"
when the variable had a named type annotation.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Adds spread operator for records, allowing concise record updates:
let p2 = { ...p, x: 5.0 }
Changes across the full pipeline:
- Lexer: new DotDotDot (...) token
- AST: optional spread field on Record variant
- Parser: detect ... at start of record expression
- Typechecker: merge spread record fields with explicit overrides
- Interpreter: evaluate spread, overlay explicit fields
- JS backend: emit native JS spread syntax
- C backend: copy spread into temp, assign overrides
- Formatter, linter, LSP, symbol table: propagate spread
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
BUG-004: Add ++ operator for string and list concatenation across all
backends (interpreter, C, JS) with type checking and formatting support.
BUG-001: Auto-invoke top-level `let main = fn () => ...` when main is
a zero-parameter function, instead of just printing the function value.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Expand type aliases via unify_with_env() everywhere in the type checker,
not just in a few places. This fixes named record types like
`type Vec2 = { x: Float, y: Float }` — they now properly unify with
anonymous records and support field access (v.x, v.y).
Also adds scripts/validate.sh for automated full-suite regression
testing (Rust tests + all 5 package test suites + type checking).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Tuple index: `pair.0`, `pair.1` syntax across parser, typechecker,
interpreter, C/JS backends, formatter, linter, and symbol table
- Multi-line function args: allow newlines inside argument lists
- Fix effect unification for callback parameters (empty expected
effects means "no constraint", not "must be pure")
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add inlay type hints for let bindings, parameter name hints at call sites,
behavioral property documentation in hover, and long signature wrapping.
- Inlay hints: show inferred types for let bindings without annotations
- Parameter hints: show param names at call sites for multi-arg functions
- Hover: wrap long signatures, show behavioral property docs (pure, total, etc.)
- Rich docs: detailed hover for keywords like pure, total, idempotent, run, with
- TypeChecker: expose get_inferred_type() for LSP consumption
- Symbol table: include behavioral properties in function type signatures
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Implements full PostgreSQL support through the Postgres effect:
- connect(connStr): Connect to PostgreSQL database
- close(conn): Close connection
- execute(conn, sql): Execute INSERT/UPDATE/DELETE, return affected rows
- query(conn, sql): Execute SELECT, return all rows as records
- queryOne(conn, sql): Execute SELECT, return first row as Option
- beginTx(conn): Start transaction
- commit(conn): Commit transaction
- rollback(conn): Rollback transaction
Includes:
- Connection tracking with connection IDs
- Row mapping to Lux records with field access
- Transaction support
- Example: examples/postgres_demo.lux
- Documentation in docs/guide/11-databases.md
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add ErrorCode enum with categorized codes (E01xx parse, E02xx type,
E03xx name, E04xx effect, E05xx pattern, E06xx module, E07xx behavioral)
- Extend Diagnostic struct with error code, expected/actual types, and
secondary spans
- Add format_type_diff() for visual type comparison in error messages
- Add help URLs linking to lux-lang.dev/errors/{code}
- Update typechecker, parser, and interpreter to use error codes
- Categorize errors with specific codes and helpful hints
Error messages now show:
- Error code in header: -- ERROR[E0301] ──
- Clear error category title
- Visual type diff for type mismatches
- Context-aware hints
- "Learn more" URL for documentation
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add String.fromChar, chars, substring, toUpper, toLower, replace,
startsWith, endsWith, join to C backend
- Fix record type alias unification by adding expand_type_alias and
unify_with_env functions
- Update docs to reflect current implementation status
- Clean up outdated roadmap items and fix inconsistencies
- Add comprehensive language comparison document
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Parser and typechecker updates for new features
- Schema evolution refinements
- Type system enhancements
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Record equality: add Record case to values_equal in interpreter
- Invalid escapes: error on unknown escape sequences in lexer
- Unknown effects: validate effect names in check_function with suggestions
- Circular types: add DFS cycle detection in check_type_cycles
- Parser: require | for enum variants, enabling proper type alias syntax
All 265 tests pass.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add Test effect with operations: assert, assertEqual, assertNotEqual,
assertTrue, assertFalse, fail
- Implement Test effect handlers in interpreter with TestResults tracking
- Add values_equal method for comparing Value types in tests
- Update lux test command to discover and run test_* functions
- Create example test files: test_math.lux, test_lists.lux
- Add TESTING_DESIGN.md documentation
- Fix AST mismatches in C backend and compiler.rs for compatibility
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Schema Evolution:
- Preserve version info in type resolution (Type::Versioned)
- Track versioned type declarations in typechecker
- Detect version mismatches at compile time (@v1 vs @v2 errors)
- Support @v2+ (at least) and @latest version constraints
- Store migrations for future auto-migration support
- Fix let bindings to preserve declared type annotations
HTTP Server Effect:
- Add HttpServer effect with listen, accept, respond, respondWithHeaders, stop
- Implement blocking request handling via tiny_http
- Request record includes method, path, body, headers
- Add http_server.lux example with routing via pattern matching
- Add type-checking test for HttpServer effect
Tests: 222 passing (up from 217)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add Http effect for making HTTP requests:
- Http.get(url) - GET request
- Http.post(url, body) - POST with string body
- Http.postJson(url, json) - POST with JSON body
- Http.put(url, body) - PUT request
- Http.delete(url) - DELETE request
Returns Result<HttpResponse, String> where HttpResponse contains
status code, body, and headers.
Includes reqwest dependency with blocking client, OpenSSL support
in flake.nix, and example at examples/http.lux demonstrating
API requests with JSON parsing.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Adds two essential effects that enable Lux to interact with the system:
File effect:
- read(path) - Read file contents as string
- write(path, content) - Write string to file
- append(path, content) - Append to file
- exists(path) - Check if file/directory exists
- delete(path) - Delete a file
- readDir(path) - List directory contents
- isDir(path) - Check if path is directory
- mkdir(path) - Create directory (including parents)
Process effect:
- exec(cmd) - Run shell command, return stdout
- execStatus(cmd) - Run command, return exit code
- env(name) - Get environment variable (returns Option)
- args() - Get command line arguments
- exit(code) - Exit program with code
- cwd() - Get current working directory
- setCwd(path) - Change working directory
Also fixes formatter bug with empty handler blocks in `run ... with {}`.
These effects make Lux capable of writing real CLI tools and scripts.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add Random and Time effects for random number generation and
time-based operations. These effects can be used in any
effectful code block.
Random effect operations:
- Random.int(min, max) - random integer in range [min, max]
- Random.float() - random float in range [0.0, 1.0)
- Random.bool() - random boolean
Time effect operations:
- Time.now() - current Unix timestamp in milliseconds
- Time.sleep(ms) - sleep for specified milliseconds
Changes:
- Add rand crate dependency
- Add Random and Time effect definitions to types.rs
- Add effects to built-in effects list in typechecker
- Implement effect handlers in interpreter
- Add 4 new tests for Random and Time effects
- Add examples/random.lux demonstrating usage
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add runtime support for the State, Reader, and Fail effects that
were already defined in the type system. These effects can now be
used in effectful code blocks.
Changes:
- Add builtin_state and builtin_reader fields to Interpreter
- Implement State.get and State.put in handle_builtin_effect
- Implement Reader.ask in handle_builtin_effect
- Add Reader effect definition to types.rs
- Add Reader to built-in effects list in typechecker
- Add set_state/get_state/set_reader/get_reader methods
- Add 6 new tests for built-in effects
- Add examples/builtin_effects.lux demonstrating usage
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add Levenshtein distance-based similarity matching for undefined
variables, unknown types, unknown effects, and unknown traits.
When a name is not found, the error now suggests similar names
within edit distance 2.
Changes:
- Add levenshtein_distance() function to diagnostics module
- Add find_similar_names() and format_did_you_mean() helpers
- Update typechecker to suggest similar names for:
- Undefined variables
- Unknown types
- Unknown effects
- Unknown traits
- Add 17 new tests for similarity matching
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add full support for user-defined generic types and functions:
- Add type_params field to TypeChecker to track type parameters in scope
- Update resolve_type() to resolve type parameters to their bound variables
- Update function_type() to bind type parameters and return polymorphic TypeScheme
- Update type declaration handling for generic ADTs (e.g., Pair<A, B>)
Generic functions and types now work:
fn identity<T>(x: T): T = x
type Pair<A, B> = | MkPair(A, B)
fn first<A, B>(p: Pair<A, B>): A = ...
Add examples/generics.lux demonstrating:
- Generic identity function
- Generic Pair type with first/second accessors
- Generic mapOption function
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add string concatenation support to + operator in typechecker
- Register ADT constructors in both type environment and interpreter
- Bind handlers as values so they can be referenced in run...with
- Fix effect checking to use subset instead of exact match
- Add built-in effects (Console, Fail, State) to run block contexts
- Suppress dead code warnings in diagnostics, modules, parser
Update all example programs with:
- Expected output documented in comments
- Proper run...with statements to execute code
Add new example programs:
- behavioral.lux: pure, idempotent, deterministic, commutative functions
- pipelines.lux: pipe operator demonstrations
- statemachine.lux: ADT-based state machines
- tailcall.lux: tail call optimization examples
- traits.lux: type classes and pattern matching
Add documentation:
- docs/IMPLEMENTATION_PLAN.md: feature roadmap and status
- docs/PERFORMANCE_AND_TRADEOFFS.md: performance analysis
Add benchmarks for performance testing.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add automatic effect inference for functions and lambdas that don't
explicitly declare their effects. The implementation:
- Tracks inferred effects during type checking via `inferred_effects`
- Uses `inferring_effects` flag to switch between validation and inference
- Functions without explicit `with {Effects}` have their effects inferred
- Lambda expressions also support effect inference
- When effects are explicitly declared, validates that inferred effects
are a subset of declared effects
- Pure functions are checked against both declared and inferred effects
This makes the effect system more ergonomic by not requiring explicit
effect annotations for every function while still maintaining safety.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add support for type classes (traits) with full parsing, type checking, and
validation. The implementation includes:
- Trait declarations: trait Show { fn show(x: T): String }
- Trait implementations: impl Show for Int { fn show(x: Int) = ... }
- Super traits: trait Ord: Eq { ... }
- Trait constraints in where clauses: where T: Show + Eq
- Type parameters on traits: trait Functor<F> { ... }
- Default method implementations
- Validation of required method implementations
This provides a foundation for ad-hoc polymorphism and enables
more expressive type-safe abstractions.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
REPL improvements:
- Tab completion for keywords, commands, and user definitions
- Persistent history saved to ~/.lux_history
- Better line editing with Emacs keybindings
- Ctrl-C to cancel input, Ctrl-D to exit
- History search with Ctrl-R
New commands:
- :info <name> - Show type information for a binding
- :env - List user-defined bindings with types
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implements the exhaustiveness algorithm to detect non-exhaustive pattern matches:
- Detects missing Bool patterns (true/false)
- Detects missing Option patterns (Some/None)
- Detects missing Result patterns (Ok/Err)
- Recognizes wildcards and variable patterns as catch-alls
- Warns about redundant patterns after catch-all patterns
- Integrates with the type checker to report errors
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implement beautiful, informative error messages inspired by Elm:
- Rich diagnostic rendering with source code snippets
- Colored output with proper underlines showing error locations
- Categorized error titles (Type Mismatch, Unknown Name, etc.)
- Contextual hints and suggestions for common errors
- Support for type errors, runtime errors, and parse errors
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implement behavioral properties for functions including:
- Property annotations: is pure, is total, is idempotent, is deterministic, is commutative
- Where clause constraints: where F is pure
- Result refinements: where result >= 0 (parsing only, not enforced)
Key changes:
- AST: BehavioralProperty enum, WhereClause enum, updated FunctionDecl
- Lexer: Added keywords (is, pure, total, idempotent, deterministic, commutative, where, assume)
- Parser: parse_behavioral_properties(), parse_where_clauses(), parse_single_property()
- Types: PropertySet for tracking function properties, updated Function type
- Typechecker: Verify pure functions don't have effects, validate where clause type params
Properties are informational/guarantees rather than type constraints - a pure
function can be used anywhere a function is expected. Property requirements
are meant to be enforced via where clauses (future work: call-site checking).
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
