## Changelog ### 1.2.0 Released 2020-08-15 - New module `Foreign.Lua.Call`: the module offers an alternative method of exposing Haskell functions to Lua. The focus is on maintainability: types and marshaling methods are made explicit; the possibility of adding documentation and parameter names improves error messages and allows for automatic documentation extraction. Work on this module is ongoing; the interface is likely to change. Suggestions and feedback are welcome. - New types `Module`, `Field`, and new functions `registerModule`, `preloadModule`, `pushModule`, and `render` exported from `Foreign.Lua.Module`: this builds on the new `Call` module and allows the creation of documented modules as well as automatic generation of Markdown-formatted module documentation. - Export new items `nth` and `top` from Foreign.Lua.Core and Foreign.Lua. They are short-hands for `nthFromTop` and `stackTop`. - Performance improvements: Calling of Lua functions and creation of Haskell data wrapping userdata has been sped up by about 10%. This is mostly due to using of previously missed optimization opportunities. - All foreign imports have been moved to into the new `Foreign.Lua.Raw` module. This module will replace the current `Foreign.Lua.Core` module in the future and will be distributed as a separate package (likely starting with the 2.0 release); the remaining parts of the current `Core` module will be promoted one level in the module hierarchy. The `Raw` module can be used whenever the full power of HsLua is not needed. - Error-signaling of API wrapper functions has been changed: instead of returning special integer values, functions now take an additional pointer argument, which is set to the status result of the computation. The `Failable` type in Core.Error is no longer needed and has been removed. - CI builds now include GHC 8.8 and GHC 8.10, ensuring that all GHC 8.* versions are supported. ### 1.1.2 Released 2020-06-27 - Revert signature of function `pushList` to it's proper 1.1 value. This fixes a mistake which caused the 1.1.1 release to be in violation of the PVP versioning policy. - Module Foreign.Lua.Peek: add function `pushKeyValuePairs` (Alex Loomis). ### 1.1.1 Released 2020-06-02 *WARNING*: This version does not conform to the PVP versioning policy, due to a unintended signature change of function `pushList`. It is recommended not to use this version. - New module Foreign.Lua.Push: provides functions which marshal and push Haskell values onto Lua's stack. Most functions in Foreign.Lua.Types.Pushable are now defined using functions from this module. - New module Foreign.Lua.Peek: provides functions which unmarshal and retrieve Haskell values from Lua's stack. Contrary to `peek` from Foreign.Lua.Types.Peekable, the peeker functions in this module will never throw errors, but use an `Either` type to signal retrieval failure. The error type `PeekError` should not be considered final and will likely be subject to change in later versions. - Module Foreign.Lua.Utf8: never throw errors when decoding UTF-8 strings. Invalid UTF-8 input bytes no longer cause exceptions, but are replaced with the Unicode replacement character U+FFFD. - Fixed missing and faulty Haddock documentation. - Fixed a bug which caused unnecessary use of strings to represent floating point numbers under certain configurations. ### 1.1.0 Released 2020-03-25. **WARNING:** The changes in this release are experimental. It is recommended to skip this release unless the newly introduced features are required. - Allow custom error handling: conversion of Lua errors to Haskell exceptions and back is made configurable. Users can define their own exception/error handling strategies, even opening up the option to pass arbitrary exceptions through Lua. - New types exported from `Foreign.Lua.Types`: - `ErrorConversion`: defines the ways in which exceptions and errors are handled and converted. - `LuaEnvironment`: environment in which Lua computations are evaluated. Contains the Lua interpreter state and the error conversion strategy. - The environment of the `Lua` type is changed from a plain Lua `State` to the above mentioned `LuaEnvironment`. - New functions `run'` is exported from `Foreign.Lua.Util` and `Foreign.Lua`: it is analogous to `run`, but allows to run computations with a custom error conversion strategy. - New function `runWithConverter` exported from `Foreign.Lua.Core.Types` and `Foreign.Lua.Core`; like `run'`, but takes a custom state. - New function `unsafeRunWith` exported from `Foreign.Lua.Core.Types` and `Foreign.Lua.Core`; runs a computation without proper error handling. - New function `errorConversion` exported from `Foreign.Lua.Core.Types` and `Foreign.Lua.Core`: extract the error conversion strategy from the Lua type. - New function `throwErrorAsException` exported from `Foreign.Lua.Core.Error` and `Foreign.Lua.Core`: throws a Lua error as Haskell exception, using the current error conversion strategy. - Function `runWith` is moved from module `Foreign.Lua.Core` to `Foreign.Lua.Util`. - The module `Foreign.Lua.Utf8` is now exported. ### 1.0.3.2 Released 2019-08-21. - Added flag to use hardcoded values for registry keys: The names of the registry keys used to store package information are available as CPP values from file lauxlib.h since Lua 5.3.4; compiling HsLua against older Lua versions was not possible, as those values were expected to exist. The respective values are now hardcoded into HsLua, and a new flag `hardcode-reg-key` is introduced, which will cause the use of these hardcoded values instead of those defined in lauxlib.h. Using this flag makes it possible to compile hslua against all Lua 5.3.* versions. - Added missing C files for benchmarking to list of *extra-source-files*. ### 1.0.3.1 Released 2019-05-08. - Prevent filenames being treated as strings in debug messages. Lua's `loadbuffer` takes a `source` description as an argument, which is used for debug messages. The `loadfile` function now adds a special prefix (`@`) to `source`, thus marking it as a filename. ### 1.0.3 Released 2019-05-04. - New module `Foreign.Lua.Module`, containing helper functions to define and load modules from Haskell. - Improve documentation of `open` (many thanks to Christian Charukiewicz.) ### 1.0.2 Released 2019-01-05. - Fixed cross-compilation: placement of C import declarations were fixed, thereby resolving issues with cross-compilation. (Vanessa McHale and Faraz Maleknia) - Added .gitattributes file, fixing the wrong language classification of the GitHub repository. (Vanessa McHale) - Improved `toHaskellFunction` documentation. The documentation is now more specific on which Haskell exceptions are caught and which will lead to crashes. ### 1.0.1 - Exposed more functions from Lua's `lauxlib` library: + `getmetafield`, + `getmetatable'`, + `getsubtable`, and + `traceback`. The function `getsubtable` is a reimplementation instead of a wrapper to the C function for simplicity (thereby avoiding additional C wrappers). - Fixed tests for GHC 8.6 by no longer depending on failable pattern matching. ### 1.0.0 #### New features - Error handling at language borders has been vastly improved and is now mostly automatic. Haskell's `Foreign.Lua.Exception`s are transformed into Lua errors and *vice versa*. Lua-side wrappers are no longer necessary. - Haskell functions are no longer pushed as userdata by `pushHaskellFunction`, but as C functions. This simplifies tasks where Lua expects true function objects object (for example when looking for module loaders). - Added stack instance for + Data.Set.Set, + Integer, + Int, + Float, and + Double. Instances for numbers fall back to strings when the representation as a Lua number would cause a loss of precision. - Haskell functions pushed with `pushHaskellFunction` can now be garbage collected by Lua without having to call back into Haskell. The callback into Haskell by the GC had previously caused programs to hang in some situations. - Bindings to more Lua C API functions and macros: `isinteger`, `load`, `loadbuffer`, and `pushglobaltable`. - Any Haskell value can be pushed to the Lua stack as userdata via `pushAny` and retrieved via `peekAny`. Additional functions are provided to setup the userdata metatable. - The C preprocessor constants `LUA_LOADED_TABLE` and `LUA_PRELOAD_TABLE` are made available as `loadedTableRegistryField` and `preloadTableRegistryField`, respectively. - Additional small helper functions: + `peekRead` -- read value from a string. + `popValue` -- peek value at the top of the Lua stack, then remove it from the stack regardless of whether peeking was successful or not. #### Naming - The *Lua* prefix was removed from types (`State`, `Integer`, `Number`, `Exception`) and the respective infix from functions (`try`, `run`, `runWith`, `runEither`). HsLua should be imported qualified to avoid name collisions. - Terminology now consistently uses *exception* to refer to Haskell exceptions, and *error* for Lua errors; function names changed accordingly (`throwException`, `catchException`, `withExceptionMessage`). - Module *Foreign.Lua.Api* was renamed to *Foreign.Lua.Core*. - *Foreign.Lua.lerror* was renamed to *Foreign.Lua.error*. - Typeclass *ToLuaStack* was renamed to *Pushable*. - Typeclass *FromLuaStack* was renamed to *Peekable*. - Cabal flag *use-pkgconfig* was renamed to *pkg-config* (which is the flag name used by other projects such a zlib). #### Type signatures - The return value of `lua_newuserdata` is *CSize* (was *CInt*). - Table index parameter in `rawgeti` and `rawseti` must be of type *LuaInteger*, but were of type *Int*. - The number of upvalues passed to `pushcclosure` must be of type *NumArgs*. - `Lua.error` has type *Lua NumResults*, simplifying its use in HaskellFunctions. - Retrieval functions which can fail, i.e. `tocfunction`, `tointeger`, `tonumber`, `tostring`, `tothread`, and `touserdata`, use the *Maybe* type to indicate success or failure, avoiding the need to perform additional checks. #### Removed Features - Support for Lua versions before 5.3 has been dropped. - Support for GHC 7.8 has been dropped. - `wrapHaskellFunction` has been made internal and is no longer exported. #### Changed behavior - Peekable instances for numbers and strings became more forgiving. Peeking of basic types now follows Lua's default conversion rules: + numbers can be given as strings, and *vice versa*; + any value can be converted into a boolean -- only `nil` and `false` are peeked as `False`, all other as `True`. #### Other - Many internal improvements and additions such as a benchmarking suite, code cleanups, better tests, etc. ### 0.9.5.{1,2} - Relaxed upper bound on *exceptions*. ### 0.9.5 - Provide Optional as a replacement for OrNil. Exports of the latter have been fixed. - Provide utility function `raiseError`: Its argument will be thrown as an error in Lua. - Add `modifyLuaError`: The function lives in Foreign.Lua.Error and allows to alter error messages. This is most useful for amending errors with additional information. - Fixed a bug in `toList` which left a element on the stack if deserializing that element lead to an error. This also affected the FromLuaStack instance for lists. - Fixed a bug in `pairsFromTable` which left a key-value pair on the stack if either of them could not be read into the expected type. This also affected the FromLuaStack instance for Map. ### 0.9.4 - Make Lua an instance of MonadMask: MonadMask from Control.Monad.Catch allows to mask asynchronous exceptions. This allows to define a finalizer for Lua operations. - Add functions and constants to refer to stack indices: The functions `nthFromBottom`, `nthFromTop` as well as the constants `stackTop` and `stackBottom` have been introduced. Numeric constants are less clear, and named constants can aid readability. - Add type OrNil: This type can be used when dealing with optional arguments to Lua functions. - Add function absindex: it converts the acceptable index `idx` into an equivalent absolute index (that is, one that does not depend on the stack top). The function calls `lua_absindex` when compiled with Lua 5.2 or later; for Lua 5.1, it is reimplemented in Haskell. - Functions in `tasty` which have been deprecated have been replaced with non-deprecated alternatives. ### 0.9.3 - Re-export more FunctionCalling helpers in `Foreign.Lua`: The typeclass `ToHaskellFunction` and the helper function `toHaskellFunction` are useful when working with functions. Importing them separately from `Foreign.Lua.FunctionCalling` was an unnecessary burden; they are therefor now re-exported by the main module. - Export registry-relatd constants `refnil` and `noref`: The constants are related to Lua's registry functions (`ref` and `unref`). - Add helper to convert functions into CFunction: A new helper `wrapHaskellFunction` is provided. It expects a HaskellImportedFunction userdata (as produced by `pushHaskellFunction`) on top of the stack and replaces it with a C function. The new function converts error values generated with `lerror` into Lua errors, i.e. it calls `lua_error`. - Add utility function `setglobal'`: It works like `setglobal`, but works with packages and nested tables (dot-notation only). ### 0.9.2 - Add cabal flag 'export-dynamic': Default behavior is to include all symbols in the dynamic symbol table, as this enables users to load dynamic lua libraries. However, it is sometimes desirable to disable, e.g., when compiling a fully static binary. See jgm/pandoc#3986. ### 0.9.1 - Increase user-friendlyness of error messages: The error message returned by `toHaskellFunction` hinted at the fact that the failing function is a Haskell function. This is mostly unnecessary information and might have confused users. ### 0.9.0 - Added cabal flag to allow fully safe garbage collection: Lua garbage collection can occur in most of the API functions, even in those usually not calling back into haskell and hence marked as optimizable. The effect of this is that finalizers which call Haskell functions will cause the program to hang. A new flag `allow-unsafe-gc` is introduced and enabled by default. Disabling this flag will mark more C API functions as potentially calling back into Haskell. This has a serious performance impact. - `FromLuaStack` and `ToLuaStack` instances for lazy ByteStrings are added. - None-string error messages are handled properly: Lua allows error messages to be of any type, but the haskell error handlers expected string values. Tables, booleans, and other non-string values are now handled as well and converted to strings. ### 0.8.0 - Use newtype definitions instead of type aliases for LuaNumber and LuaInteger. This makes it easier to ensure the correct numeric instances in situations where Lua might have been compiled with 32-bit numbers. - Instances of `FromLuaStack` and `ToLuaStack` for `Int` are removed. The correctness of these instances cannot be guaranteed if Lua was compiled with a non-standard integer type. ### 0.7.1 - The flag `lua_32bits` was added to allow users to compile Lua for 32-bit systems. - When reading a list, throw an error if the lua value isn't a table instead of silently returning an empty list. ### 0.7.0 - Tuples from pairs to octuples have been made instances of `FromLuaStack` and `ToLuaStack`. - New functions `dostring` and `dofile` are provided to load and run strings and files in a single step. - `LuaStatus` was renamed to `Status`, the *Lua* prefix was removed from its type constructors. - The constructor `ErrFile` was added to `Status`. It is returned by `loadfile` if the file cannot be read. - Remove unused FFI bindings and unused types, including all functions unsafe to use from within Haskell and the library functions added with 0.5.0. Users with special requirements should define their own wrappers and raw bindings. - The module *Foreign.Lua.Api.SafeBindings* was merge into *Foreign.Lua.Api.RawBindings*. - FFI bindings are changed to use newtypes where sensible, most notably `StackIndex`, `NumArgs`, and `NumResults`, but also the newly introduced newtypes `StatusCode`, `TypeCode`, and `LuaBool`. - Add functions `tointegerx` and `tonumberx` which can be used to get and check values from the stack in a single step. - The signature of `concat` was changed from `Int -> Lua ()` to `NumArgs -> Lua ()`. - The signature of `loadfile` was changed from `String -> Lua Int` to `String -> Lua Status`. - The type `LTYPE` was renamed to `Type`, its constructors were renamed to follow the pattern `Type`. `LuaRelation` was renamed to `RelationalOperator`, the *Lua* prefix was removed from its constructors. - Add function `tolist` to allow getting a generic list from the stack without having to worry about the overlapping instance with `[Char]`. ### 0.6.0 * Supported Lua Versions now include Lua 5.2 and Lua 5.3. LuaJIT and Lua 5.1 remain supported as well. * Flag `use-pkgconfig` was added to allow discovery of library and include paths via pkg-config. Setting a specific Lua version flag now implies `system-lua`. (Sean Proctor) * The module was renamed from `Scripting.Lua` to `Foreign.Lua`. The code is now split over multiple sub-modules. Files processed with hsc2hs are restricted to Foreign.Lua.Api. * A `Lua` monad (reader monad over LuaState) is introduced. Functions which took a LuaState as their first argument are changed into monadic functions within that monad. * Error handling has been redesigned completely. A new LuaException was introduced and is thrown in unexpected situations. Errors in lua which are leading to a `longjmp` are now caught with the help of additional C wrapper functions. Those no longer lead to uncontrolled program termination but are converted into a LuaException. * `peek` no longer returns `Maybe a` but just `a`. A LuaException is thrown if an error occurs (i.e. in situtations where Nothing would have been returned previously). * The `StackValue` typeclass has been split into `FromLuaStack` and `ToLuaStack`. Instances not satisfying the law `x == push x *> peek (-1)` have been dropped. * Documentation of API functions was improved. Most docstrings have been copied from the official Lua manual, enriched with proper markup and links, and changed to properly describe hslua specifics when necessary. * Example programs have been moved to a separate repository. * Unused files were removed. (Sean Proctor) ### 0.5.0 * New raw functions for `luaopen_base`, `luaopen_package`, `luaopen_string`, `luaopen_table`, `luaopen_math`, `luaopen_io`, `luaopen_os`, `luaopen_debug` and their high-level wrappers (with names `openbase`, `opentable` etc.) implemented. * Remove custom versions of `loadfile` and `loadstring`. * Drop support for GHC versions < 7.8, avoid compiler warnings. * Ensure no symbols are stripped when linking the bundled lua interpreter. * Simplify `tostring` function definition. (Sean Proctor) * Explicitly deprecate `strlen`. (Sean Proctor) * Add links to lua documentation for functions wrapping the official lua C API. (Sean Proctor). ### 0.4.1 * Bugfix(#30): `tolist` wasn't popping elements of the list from stack. ### 0.4.0 * `pushstring` and `tostring` now uses `ByteString` instead of `[Char]`. * `StackValue [Char]` instance is removed, `StackValue ByteString` is added. * `StackValue a => StackValue [a]` instance is added. It pushes a Lua array to the stack. `pushlist`, `islist` and `tolist` functions are added. * Type errors in Haskell functions now propagated differently. See the `Scripting.Lua` documentation for detailed explanation. This should fix segfaults reported several times. * `lua_error` function is removed, it's never safe to call in Haskell. Related issues and pull requests: #12, #26, #24, #23, #18. ### 0.3.14 * Pkgconf-based setup removed. Cabal is now using `extra-libraries` to link with Lua. * `luajit` flag is added to link hslua with LuaJIT. ### 0.3.13 * Small bugfix related with GHCi running under Windows. ### 0.3.12 * `pushrawhsfunction` and `registerrawhsfunction` functions are added. * `apicheck` flag is added to Cabal package to enable Lua API checking. (useful for debugging) ### 0.3.11 * `luaL_ref` and `luaL_unref` functions are added.