nimterop/CHANGES.md

Nimterop Change History

Version 0.5.0

This release introduces a new backend for wrapper generation dubbed ast2 that leverages the Nim compiler AST and renderer. The new design simplifies feature development and already includes all the functionality of the legacy algorithm plus fixes for several open issues.

The new backend can be leveraged with the -f:ast2 flag to toast or flags = "-f:ast2" to cImport(). The legacy algorithm will be the default backend for this release but no new functionality or bugfixes are expected going forward. Usage of the legacy algorithm will display a deprecated hint to encourage users to test their wrappers with -f:ast2 and remove any overrides that the new algorithm supports.

Version 0.6.0 of Nimterop will make ast2 the default backend and the legacy algorithm will be removed altogether.

See the full list of changes here:

https://github.com/nimterop/nimterop/compare/v0.4.4...v0.5.0

Breaking changes

• Nimterop used to default to C++ mode for preprocessing and tree-sitter parsing in all cases unless explicitly informed to use C mode. This has been changed and is now detected based on the file extension. This means some existing wrappers could break since they might contain C++ code or include C++ headers like #include <string> which will not work in C mode. Explicitly setting mode = "cpp" or -mcpp should fix such issues. #176

• Enums were originally being mapped to distint int - this has been changed to distinct cint since the sizes are incorrect on 64-bit and is especially noticeable when types or unions have enum fields.

• static inline functions are no longer wrapped by the legacy backend. The ast2 backend correctly generates wrappers for such functions but they are only generated when --noHeader | -H is not in effect. This is because such functions do not exist in the binary and can only be referenced when the header is compiled in.

• Support for Nim v0.19.6 has been dropped and the test matrix now covers v0.20.2, v1.0.6, v1.2.0 and devel.

New functionality

• Nimterop can now skip generating the {.header.} pragma when the --noHeader | -H flag is used. This skips the header file #include in the generated code and allows creation of wrappers that do not require presence of the header during compile time. Note that static inline functions will only be wrapped when the header is compiled in. This change applies to both ast2 and the legacy backend, although ast2 can also generate wrappers with both {.header.} and {.dynlib.} in effect enabling type size checking with -d:checkAbi. More information is available in the README.md. #169

• ast2 includes support for various C constructs that were issues with the legacy backend. These changes should reduce the reliance on cOverride() and existing wrappers should attempt to clean up such sections where possible.

  • N-dimensional arrays and pointers - #54
  • Synomyms for types - #74
  • Varargs support - #76
  • Nested structs, unions and enums - #137 #147
  • Forward declarations of types - #148
  • Nested function pointers - #155 #156
  • Various enum fixes - #159 #171
  • Map int arr[] to arr: UncheckedArray[cint] - #174

• ast2 also includes an advanced expression parser that can reliably handle constructs typically seen with #define statements and enumeration values:

  • Integers + integer like expressions (hex, octal, suffixes)
  • Floating point expressions
  • Strings and character literals, including C's escape characters
  • Math operators + - / *
  • Some Unary operators - ! ~
  • Any identifiers
  • C type descriptors int char etc
  • Boolean values true false
  • Shift, cast, math or sizeof expressions
  • Most type coercions

• Wrappers can now point to an external plugin file with cPluginPath() instead of having to declaring plugins inline with cPlugin(). This allows multiple wrappers to share the same plugin. #181

• cImport() adds support for importing multiple headers in a single call - this enables support for libraries that have many header files that include shared headers and typically cannot be imported in multiple cImport() calls since it results in duplicate symbols. Calling toast with multiple headers uses the same algorithm.

• ast2 now creates Nim doc comments instead of reqular comments which get rendered when the wrapper is run through nim doc or the buildDocs() API. #197

• toast now includes --replace | -G to manipulate identifier names beyond --prefix and --suffix. -G:X=Y replaces X with Y and -G:@_[_]+=_ replaces multiple _ with a single instance using the @ prefix to enable regular expressions.

• toast also includes --typeMap | -T to map C types to another type. E.g. --typeMap:GLint64=int64 generates a wrapper where all instances of GLint64 are remapped to the Nim type int64 and GLint64 is not defined. (since v0.5.2)

• CLI flags can now be specified one or more per line in a file and path provided to toast. They will be expanded in place. #196 (since v0.5.3)

• Nimterop is now able to detect Nim configuration of projects and can better handle cases where defaults such as nimcacheDir or nimblePath are overridden. This especially enables better interop with workflows that do not depend on Nimble. #151 #153

• Nimterop defaults to cmake, followed by autoconf for building libraries with getHeader(). It is now possible to change the order of discovery with the buildType value. #200