Replace the char* based string buffer with a proper String struct that stores both the buffer pointer and length, eliminating strlen() calls in symbol table lookups. Update all symbol table consumers in debug printing, VM method resolution, and GC marking to access the .buffer field. Refactor Value union to use anonymous struct for num/obj fields, and change Obj flags to a bool marked field. Adjust ALLOCATE_FLEX macro to accept separate main type and array type parameters. Add regression test for map subscript on empty map returning null.
The previous implementation of hashValue had UNREACHABLE() placed after the switch statement, which could be reached when using NaN-tagging mode. This fix moves UNREACHABLE() into default cases within each switch branch, ensuring it's only triggered for truly unreachable paths.
Additionally, the Value struct is refactored to use an anonymous union for num and obj fields, preventing undefined behavior from accessing inactive union members. All related macros and inline functions (AS_OBJ, wrenValuesSame, wrenObjectToValue, wrenValueToNum, wrenNumToValue, and singleton value definitions) are updated to use the new `as` union member access pattern.
The macro now takes a main type, array element type, and element count, computing the total allocation as `sizeof(mainType) + sizeof(arrayType) * count`. This improves type safety and clarity at all call sites, which are updated to pass the element type (Upvalue*, Value, char) instead of manually computing byte sizes.
Introduce conditional detection of Darwin target to set appropriate shared library flags and extension (.dylib instead of .so). Refactor static and shared library build targets into combined `libwren` and `libwrend` phony targets that produce both .a and .dylib/.so files, and update .gitignore to exclude the new .dylib artifacts.
Remove the FLAG_MARKED enum and ObjFlags bitfield, replacing them with a dedicated bool `marked` member in the Obj struct. Update all references in wren_value.c and wren_vm.c to use direct boolean assignment and checks instead of bitwise flag operations. This simplifies the GC marking logic and eliminates the need for manual bit manipulation.
Add early return of UINT32_MAX when map capacity is zero in wrenMapFind,
preventing a crash from modulo operation on zero during hash index calculation.
Includes regression test verifying subscript access on empty map returns null.
Remove the FLAG_MARKED bitfield enum and replace the packed unsigned int flags field with a dedicated bool marked member in the Obj base struct. Update all references in wren_value.c and wren_vm.c to use direct boolean assignment and checks instead of bitwise operations, simplifying the garbage collection marking logic and eliminating the TODO about storing the flag off to the side.
Remove the dedicated string equality operators (string_eqeq, string_bangeq) and their NATIVE registrations, switching object_eqeq and object_bangeq to use the generic wrenValuesEqual instead of wrenValuesSame. Also fix wrenValuesEqual to use memcmp instead of strncmp for string comparison. Add a new test file test/range/equality.wren verifying inclusive and exclusive range equality and inequality.
Eliminate the LIST opcode and its interpreter case, debug printing, and enum entry. Instead compile list literals by loading the List class, calling its constructor, then emitting DUP, element expression, CALL_1 for add(), and POP for each element. This removes interpreter loop code and lifts the previous 255-element limit on list literals.
Implement hexadecimal number literal support in the Wren compiler by adding a `number` field to the Parser struct, a `readHexDigit` helper that returns -1 for invalid hex chars, and a `readHexNumber` function that skips the 'x' prefix, accumulates hex digits, converts via strtol, and emits a TOKEN_NUMBER. Update `readNumber` to remove the TODO placeholder for hex support. Include test cases for valid hex literals (0xFF, 0x09, negative -0xFF) and an invalid hex literal (2xFF) that triggers a lex error.
Implement `containsKey()` native method on Map that returns a boolean indicating whether the given key exists in the map. Add `validateKey()` helper to reject non-value-type keys (objects, lists, fibers, etc.) with a clear runtime error. Refactor `wrenMapGet()` signature to return success/failure via bool and output the value through an out-parameter, enabling both `containsKey()` and the existing subscript operator to share the same key validation and lookup logic. Update `map_subscript` to return `null` instead of crashing when a key is not found. Add test cases for `containsKey` success/failure, and runtime error tests for invalid key types in subscript getter, setter, and containsKey.
Add MapKeySequence and MapValueSequence classes in core.wren to expose iterable key and value views on Map instances. Implement native iterate_, keyIteratorValue_, and valueIteratorValue_ primitives in wren_core.c to support these sequences. Replace the stub Map.toString with a full implementation that iterates keys and formats each entry as "key: value", handling empty maps and nested maps correctly. Include comprehensive test suites for key iteration, value iteration, iterator type validation, and toString output across multiple orderings.
Add DEF_NATIVE(map_clear) that frees the underlying entries array and resets
capacity and count to zero, returning null. Register the "clear" method on
the Map class in wrenInitializeCore and include a test verifying the map is
emptied and the return value is null.
Add support for map literals using `{}` syntax in the compiler, replacing the previous `new Map` constructor pattern. This introduces a new `map()` grammar function that loads the Map class, instantiates it, and compiles key-value pairs using subscript setter calls. A new `CODE_DUP` bytecode is added to duplicate the map reference on the stack for each element insertion. The change includes updated test files to use literal syntax and new error tests for edge cases like EOF after colon, comma, key, or value.
Implement the core Map data structure in Wren, including the ObjMap type with
hash table storage, native methods for instantiation, subscript get/set, and
count. Add Map class declaration to core.wren with a basic toString stub.
Introduce MapEntry struct and hash table growth logic with configurable load
factor. Add test files for map creation, count tracking, key type support
(including null, bool, num, string, range, and class keys), and growth
behavior. Refactor list capacity constants into shared MIN_CAPACITY and
GROW_FACTOR macros. Change object equality operators to use wrenValuesSame
instead of wrenValuesEqual.
Add a public `arity` getter to the Fn class that returns the number of required arguments for a function. Internally rename the `numParams` field to `arity` across the codebase for consistency, update the C API parameter name from `numParams` to `arity` in `wrenDefineMethod` and `wrenDefineStaticMethod`, and adjust the error message in `callFunction` to use the new field name. Also update documentation to clarify that extra arguments are ignored rather than causing an error, and add a new test file `test/function/arity.wren` verifying arity values from 0 to 4.
Add Visual Studio 2013 solution and project files under project/msvc2013/ directory, enabling native Windows builds without MinGW. Include Marco Lizza in AUTHORS for the contribution. Fix C89 compatibility issues for MSVC: disable computed goto via _MSC_VER check, define inline as _inline for non-C++ mode, change flexible array members from empty brackets to [0] syntax, and fix char to int type for readHexDigit return value. Refactor single-line if/while/for bodies in wren_compiler.c to use braces to satisfy MSVC stricter parsing.
Add String as a subclass of Sequence in core.wren and implement the iterator protocol for strings in wren_core.c. The string_iterate native advances through UTF-8 code point boundaries, while string_iteratorValue extracts the full code point at a given byte index. Includes comprehensive test coverage for iteration, edge cases (empty strings, mid-sequence positions), and error handling for invalid iterator types and out-of-bounds indices. Also updates documentation for String, List, and Sequence classes with iterator protocol details and usage examples.
Add runtime type validation to wrenGetArgumentBool, wrenGetArgumentDouble, and
wrenGetArgumentString in src/wren_vm.c, replacing TODO comments with actual
checks that return safe defaults (false, 0.0, NULL) on type mismatch.
Remove the unused wrenReturnNull function entirely from the VM implementation.
Update include/wren.h documentation for argument accessor functions to clarify
indexing semantics (including receiver at index 0) and document the new
type-checking behavior.
The diff reorders the `children` array of the `src` group in the Xcode project file,
moving `.c` files after their corresponding `.h` headers to match a consistent
header-before-source convention.
The modulo operator was incorrectly assigned PREC_TERM precedence, causing it to
bind less tightly than multiplication and division. This change promotes it to
PREC_FACTOR, matching the standard mathematical precedence where `%` has the
same binding strength as `*` and `/`.
A test case `IO.print(13 + 1 % 7)` is added to verify the fix, expecting `14`
(equivalent to `13 + (1 % 7)`) rather than the incorrect `(13 + 1) % 7 = 0`.
Rename all instances of "pinned" objects to "temporary roots" in wren_vm.c, wren_vm.h, and wren_common.h to better describe their stack-based lifecycle. Update the WREN_MAX_PINNED constant to WREN_MAX_TEMP_ROOTS, rename the vm->pinned array to vm->tempRoots, and rename vm->numPinned to vm->numTempRoots. Adjust all related comments and assertions to reflect the new terminology, including the GC stress test comment in wren_common.h.
Refactor parameter list parsing to support bracket-delimited parameters for
subscript operators. Extract finishParameterList from parameterList to handle
the common closing logic, and add TOKEN_RIGHT_BRACKET case for error messages.
Add comprehensive test suite for subscript getters and setters with 1-3
parameters in test/method/subscript_operators.wren.
- Insert "Getting acquainted" section in contributing guide with mailing list invitation
- Add proposal link for significant changes discussion before coding
- Promote mailing list as primary contact method in getting-started page
- Add link references for list, twitter, issue, and repo in getting-started
- Relocate wren.xcodeproj into project/xcode/ subdirectory
- Remove build_xcode/ from .gitignore as it is no longer at root level
- Update all internal PBXBuildFile references to use new file paths
The AS_OBJ macro on NaN-tagged architectures was performing a direct cast from
uint64_t to Obj* which triggers a pointer-to-integer cast warning on 32-bit
MinGW where sizeof(Obj*) is 4 bytes. Adding an intermediate cast to uintptr_t
ensures the value is properly truncated before conversion to the pointer type.
Also replaces IS_SINGLETON macro usage with direct NULL_VAL/UNDEFINED_VAL
comparisons and removes the now-unused IS_SINGLETON definition.
The CalculatedRange struct is removed from the header and calculateRange now returns the start index directly while using pointer parameters for length and step, simplifying the API and reducing struct overhead.
Extract range validation logic into a reusable `calculateRange` function that handles inclusive/exclusive bounds, negative indices, and direction stepping. Add `CalculatedRange` struct to `wren_core.h` and implement string subscript tests covering forward, backward, negative, and half-negative ranges along with comprehensive error cases for out-of-bounds and non-integer range endpoints.
Replace signed `int` with unsigned `uint8_t` for field indices in LOAD_FIELD_THIS, STORE_FIELD_THIS, LOAD_FIELD, and STORE_FIELD opcodes, and with `uint16_t` for jump offsets in JUMP, LOOP, and JUMP_IF opcodes. This eliminates sign-extension overhead and enables better code generation, yielding 1-7% performance gains across binary_trees, delta_blue, fib, for, and method_call benchmarks.
The consume() function previously returned a pointer to the consumed token,
and consumeLine() returned a boolean indicating success. Both return values
were never used by any callers. This change converts both functions to void,
eliminating dead code and simplifying the interface.
Add a new public API function `wrenGetArgumentBool` to the Wren VM that
allows foreign method implementations to retrieve boolean arguments from
the foreign call slot. The implementation includes assertions for null
slot, non-negative index, and bounds checking against the number of
arguments, and uses the existing AS_BOOL macro to extract the boolean
value from the slot.
Add a new public API function `wrenReturnBool` to the Wren C API, enabling
foreign method implementations to return boolean values. The implementation
stores the boolean as a Wren BOOL_VAL in the foreign call slot and clears
the slot pointer, following the same pattern as existing `wrenReturnString`.
Also add the missing `prep` target to the .PHONY list in the Makefile and
include `<stdbool.h>` in the public header to support the `bool` type used
in the new function signature.
The `is` operator was placed at `PREC_IS` which had lower precedence than `PREC_EQUALITY`, causing expressions like `true == 10 is Num` to parse incorrectly. Moved `PREC_IS` above `PREC_EQUALITY` in the precedence enum to give `is` higher binding power than `==` and `!=`. Added precedence tests in new `test/precedence.wren` file and removed TODO comments about precedence from `test/is/is.wren`.
The prep target was missing from the .PHONY declaration, causing Make to skip
its execution when a file named 'prep' existed in the working directory. This
change ensures prep is always treated as a phony target and executed regardless
of file system state.
Add a new public API function `wrenReturnBool` to the Wren C API, allowing
foreign method implementations to return boolean values. The function
includes the necessary `stdbool.h` include in the public header and
implements the return logic by storing a BOOL_VAL in the foreign call slot,
following the same pattern as existing return functions like
`wrenReturnNull` and `wrenReturnString`.
Remove the Linux-specific `_GNU_SOURCE` macro and `getline()` usage in the REPL loop, replacing them with a fixed-size `fgets()` buffer of 1024 bytes. Also switch `snprintf` to `sprintf` in `wren_vm.c` for the field limit error message, eliminating the need for `_GNU_SOURCE` entirely.
The benchmark HTML output previously displayed abstract "score" values and scaled bars by the highest score. This change replaces scores with the actual minimum execution time in seconds (e.g., "0.15s") and scales bar widths proportionally to the highest time, making the charts directly interpretable as performance comparisons. The `run_bench` script now computes `time` from `min(result["times"])` instead of `get_score()`, and the static performance documentation is updated to reflect the new time-based values.
Update the Method Call and DeltaBlue benchmark tables with new Wren performance results (6748 and 7564 respectively), adjusting all other language scores and corresponding chart-bar width percentages to reflect the latest measurements.
Replace the C99 designated initializer syntax for `WrenConfiguration config` with explicit field assignments to avoid potential compiler compatibility issues. The change preserves the same configuration values: `reallocateFn` set to NULL, `heapGrowthPercent` and `minHeapSize` set to 0, and `initialHeapSize` set to 100 MB.
Add native `!` methods to Null, Object, Num, String, and List classes so that `!` works reliably on any value. Null returns `true`, all other types return `false` since they are considered truthy. Update documentation to describe the operator as returning the logical complement and add comprehensive tests for each type. Also fix the `all` method test to use a truthy string instead of expecting a runtime error.
Add C++98 compatibility by introducing explicit casts, replacing C99-specific constructs with macros, and updating the build system to produce C++ object files. Refactor the Value union to a plain uint64_t when WREN_NAN_TAGGING is enabled, adding helper functions for num-to-value and value-to-num conversions. Update the compiler to split emit into emit and emitShort for cleaner bytecode emission, and rename emitByte/emitShort to emitByteArg/emitShortArg.
- Replace Value union with plain uint64_t typedef under WREN_NAN_TAGGING, removing num/bits field access
- Add wrenValueToNum and wrenNumToValue helper functions for double conversion
- Remove wrenValuesEqual function from wren_value.c as bitwise comparison is now direct
- Update Makefile with CPPFLAGS for C++98 compilation and add release-cpp build target
- Add wren-cpp and libwren-cpp.a to .gitignore for C++ build artifacts
Remove the single-purpose `allocate` helper and introduce three type-safe allocation macros (`ALLOCATE`, `ALLOCATE_FLEX`, `ALLOCATE_ARRAY`) that directly invoke `wrenReallocate`. Update all call sites in `wren_value.c` — including `wrenNewSingleClass`, `wrenNewClosure`, `wrenNewFiber`, and `wrenNewFunction` — to use the appropriate macro, eliminating the need for manual sizeof calculations and improving compile-time type checking when compiling as C++.
Add explicit casts to `(Code)` in `debugPrintInstruction` for bytecode indexing, to `(char*)` in `wrenSymbolTableAdd` for heap string allocation, and to `(type*)` in the `DEFINE_BUFFER` macro's reallocation call to ensure C++ compilation compatibility without implicit conversion errors.
- Cast malloc return to char* in src/main.c to avoid C++ implicit void* conversion
- Rename emit to emitByteArg and emitShort to emitShortArg in src/wren_compiler.c to avoid conflict with new emit and emitShort helpers
- Add new emit function taking uint8_t byte and emitShort helper for 16-bit big-endian emission
- Remove stray semicolon in script/test.py
Implement `all(f)` method on Sequence class that returns true if all elements pass the predicate function. Add corresponding documentation entry for `forall(predicate)` in core-library.markdown. Include three test files covering basic functionality, non-boolean return handling, and non-function argument error cases.
Add a new singleton value `VAL_UNDEFINED` to represent globals that have been implicitly declared via forward reference but not yet explicitly defined. Introduce `wrenDeclareGlobal()` to create such entries in the global table, and modify `wrenDefineGlobal()` to check for and resolve undefined slots. Update the compiler's `findUpvalue()` to stop closure capture at method boundaries, preventing methods from closing over local variables. Refactor `wrenSymbolTableAdd()` to always add symbols without duplicate checking, moving that logic to callers. Adjust error messages in the compiler to handle EOF tokens and improve newline formatting. Fix the delta_blue benchmark by renaming the global `planner` variable to `ThePlanner` to avoid shadowing the forward-declared function.
Add support for forward references to top-level variables by implicitly
declaring unresolved capitalized names as globals during compilation.
If a real definition is not found later, a compile-time error is raised.
This enables mutual recursion at the top level and fixes issues #101 and #106.
Introduce an `UNDEFINED` singleton value to mark implicitly declared globals
that have not yet been explicitly defined. Update `wrenDeclareGlobal` to add
such entries, and modify `wrenDefineGlobal` to check for and replace undefined
placeholders. Adjust the symbol table API to allow duplicate additions for
implicit declarations. Add test cases for mutual recursion, forward references
in functions and methods, and undefined variable errors.
Replace the forward-declared `planner` variable with a capitalized `ThePlanner` name across all constraint methods and test functions, removing the TODO comment about forward declarations.
Replace sequential `if` statements with `else if` chains in `readName` so that once a keyword matches (e.g. "break"), the remaining keyword checks are skipped, fixing issue #110 where later keywords could incorrectly override an already-matched token type.
Modify `findUpvalue` in the compiler to return -1 when the enclosing function is a method, preventing closures from capturing outer local variables. Add a new `nonlocal` variable resolution path that treats capitalized identifiers as global variables rather than method receivers. Update existing test files to use capitalized global names and add new test cases for nonlocal assignment, duplicate nonlocal declarations, block scoping, and method-local variable shadowing.
Fix three typos across documentation files: 'unvalid' to 'invalid' in
doc/error-handling.txt, and 'bretheren' to 'brethren' in both
doc/site/expressions.markdown and doc/site/getting-started.markdown
Add the -g compiler flag to DEBUG_CFLAGS in the Makefile to enable
generation of debugging symbols during debug builds, allowing better
debugging with tools like GDB.
Add string type check for IO.read() prompt argument with Fiber.abort on non-string input. Implement stdin piping in test runner via // stdin: comments, allowing tests to provide input lines. Update stack trace filtering to omit built-in library frames with empty source paths. Add io/read.wren and io/read_arg_not_string.wren test cases.
Implement a new static `IO.read(prompt)` method in the IO class that writes a prompt string to stdout and reads a line from stdin into a fixed 1024-byte buffer. The C implementation adds a `MAX_READ_LEN` constant, an `ioRead` function using `fgets`, and registers the method via `wrenDefineStaticMethod`. The builtin source string is updated to include the new Wren method definition.
The nextToken function in wren_compiler.c previously only skipped spaces and carriage returns when advancing past whitespace, causing tab characters to be treated as non-whitespace tokens. This change adds '\t' to the whitespace check in both the initial case statement and the peekChar loop, ensuring tabs are properly skipped like other whitespace characters. A new test file test/whitespace.wren is added to verify correct handling of tabs in various indentation patterns and inline code positions.
Add a new test file `test/ignore_carriage_returns.wren` that sprinkles carriage
return characters (`\r`) in various positions within source code to confirm the
parser correctly ignores them as whitespace. The test includes a deliberate
compile error to validate that line numbering remains accurate despite the
presence of carriage returns.
Add a `contains(element)` method to the built-in `List` class in `builtin/core.wren` and its embedded source in `src/wren_core.c`, enabling linear search for an element. Introduce a new `Set` class example in `example/set.wren` implementing set operations (union, intersection, difference) using the new `contains` method. Update `doc/site/classes.markdown` with a warning against inheriting from built-in types due to internal bit representation constraints.
Change `fopen` mode from `"r"` to `"rb"` in `readFile()` to prevent CRLF-to-LF conversion on Windows, and add `'\r'` as a skipped whitespace character in `nextToken()` to handle carriage returns embedded in source files. This fixes parsing errors when Wren source files use Windows-style line endings.
Add a note to the classes documentation page explaining that inheriting from built-in types (Bool, Num, String, Range, List) is not supported due to internal bit representation conflicts that cause errors when invoking inherited methods on derived types.
Add a complete Set class implementation in example/set.wren with union, intersection, and set minus operations. Implement List.contains method in builtin/core.wren and its C source to support element existence checks via iteration.
When `super` is invoked at the top level without an explicit method name, the compiler previously dereferenced a NULL `enclosingClass` pointer while trying to copy the enclosing method's signature. This change adds a NULL check for `enclosingClass` in the `super_` function, setting an empty method name and zero length when the pointer is NULL, preventing the segmentation fault. Also extends the test file `super_at_top_level.wren` with additional cases for bare `super`, `super.foo("bar")`, and `super("foo")` to verify error handling for these top-level super invocations.
Rename indexOf.wren and startsWith.wren test files to index_of.wren and
starts_with.wren respectively, fix missing trailing newlines, update
string class documentation to clarify UTF-8 storage and move the
note about incorrect UTF-8 handling in the index operator, and
remove unnecessary parentheses in string_indexOf native return.
The font stylesheet link in doc/site/template.html used an explicit http:// scheme,
causing Firefox to block the request on HTTPS pages due to Mixed Content warnings.
Changed to a protocol-relative URL (//fonts.googleapis.com/...) so the browser
automatically uses the same protocol as the parent page.
The `string_subscript` native was allocating a 2-byte buffer for single-character
results, causing a one-byte over-allocation. Changed to allocate exactly 1 byte
for the character plus the null terminator handled by `wrenNewUninitializedString`.
Also fixed `wrenNewUninitializedString` to properly cast the `length` parameter
to `int` when assigning to `ObjString->length`, resolving a potential
truncation warning on 64-bit systems.
Added a test case to verify that subscript access returns a properly formed
string that compares equal to the expected character.
The lexer previously treated a leading minus sign followed by a digit as a single negative number token, which caused incorrect parsing of expressions like `1-1` and broke method calls on negative numbers. This change removes that special case, making the minus sign always a separate token, and updates all test expectations to use explicit parentheses for negative number method calls.
Introduce a `methodNotFound` helper in `wren_vm.c` that parses the symbol name to determine the number of arguments and generates a detailed error message including the argument count. Update all runtime error calls and test expectations across fiber, inheritance, method, and super test files to reflect the new format, and add new test cases for method-not-found with 1, 2, and 11 arguments.
Add a new FAQ entry explaining why Wren uses a stack-based bytecode VM
instead of a register-based one. The entry covers the trade-offs between
the two approaches, references Lua's switch to register-based VM, and
explains that Wren's operator-overloading design makes register-based
optimizations less beneficial.
Bob Nystrom