A command line tool and library for creating Common Lisp language bindings from C header files
- Generates CFFI bindings for function declarations, enums, variables, unions, and structures.
- Handles nested and anonymous structures, unions, and enums.
- Warns when it cannot produce a correct binding.
- Documentation comments from the C source files are lispified and included with the generated bindings when available.
- Provides a powerful way to customize how names are translated into lisp symbols.
libclang, which is not installed with the other Python
dependencies and not available on PyPi. It is recommended to install it first before installing
cl-bindgen. Use your distribution's package manager to install it.
libclang is installed, you can then install
source or from PyPI.
pip install cl-bindgen
git clone --depth=1 https://github.com/sdilts/cl-bindgen cd cl-bindgen pip install --user .
Processing individual files
To process individual files, use the
f command and specify one or
more files to process. By default, output will be printed to
stdout, but the output file can be specified with the
-o option. To see
a full list of options, run
cl-bindgen f -h.
# Process test.h and print the results to stdout: cl-bindgen f test.h # Process the files test1.h, test2.h, and place the output in output.lisp: cl-bindgen f -o output.lisp test1.h test2.h
Batch file processing
cl-bindgen can use a yaml file to process many header
files with a single invocation. Use the
to specify one or more batch files to process:
cl-bindgen b my_library.yaml
Batch file format
Batch files use the YAML format. Multiple documents can be contained in each input file.
output: where to place the generated code
files: a list of files to process
package: The name of the Common Lisp package of the generated file
arguments: Arguments to pass to clang
force: Ignore errors while parsing. Valid values are
To see example batch files, look in the examples directory.
Handling Include Directories and Clang Arguments
If you need to specify additional command line arguments to the clang
processor, you can use the
-a option, and list any clang arguments after.
cl-bindgen b batch_file.yaml -a -I include_dir1 -I include_dir2 # Use -- to stop collecting clang arguments: cl-bindgen f -a `pkg-config --cflags mylibrary` -- header.h
If a header file isn't found while processing the input files,
cl-bindgen will halt and produce no output. This is to avoid producing
incorrect bindings: while bindings can still be produced when header
files are missing, they are likely to be incorrect. To ignore missing
header files and other fatal errors, the
-f flag can be used:
cl-bindgen b -f batch_file.yaml cl-bindgen f -f header.c
Customizing the behavior of cl-bindgen
cl-bindgen attempts to provide a reasonable interface that is usable in most cases. However, if you need to customize how C names are converted into lisp names or embed cl-bindgen into another application, cl-bindgen is available as a library.
cl_bindgen package is broken up into three modules: the
util modules. The
processfile module provides the
functions to generate the lisp bindings, the
mangler module provides
functions to convert C names into lisp names, and the
provides functions to use batch files and cl-bingen's command line
This module exports two functions:
which work on a single header file or many, respectively. Both
functions take two arguments: the file(s) to be processed and an
ProcessOptionsclass is the way to specify how the
processing functions generate their output. It has the following
constant_manglers: See the mangler module section for what these do.
output: The path of the file where the output is placed.
":stderr"can be specified to use standard out or standard error.
package: If not
None, this specifies the package the the generated output should be placed in.
arguments: The command line arguments that should be given to the clang processor.
force: If true, then ignore errors while parsing the input files.
cl-bindgen uses a set of classes called manglers to translate C
names so that they follow lisp naming conventions. Each mangler class
provides one or more transformations to a symbol. For example, the
UnderscoreMangler class converts underscores (
_) into dashes
-). A series of manglers are applied to each C name to make it
follow lisp naming conventions.
To maximize customization, a list of manglers is associated with each type of name that can be converted. enums, variable names, typedefs, constants, and record types all use a different set of manglers.
UnderscoreMangler: Converts underscores to dashes.
ConstantMangler: Converts a string to follow Common Lisp's constant style recomendation.
KeywordMangler: Adds a
:to the beginning of a string to make it a symbol. Doesn't perform any action if the string has a package prefix.
RegexSubMangler: Substitutes the substring matched by a regex with the given string.
Mangler classes follow a simple interface:
can_mangle(string): returns true if the mangler can perform its operations on the given string
mangle(string): returns a string with the desired transformations applied.
util module provides two functions:
process_batch_file(batch_file, options): Processes the given batch file using
optionsas the default options.
dispatch_from_arguments(arguments, options): Uses the provided command line arguments to perform the actions of cl-bindgen using
optionsas the default options.
The best example of how to use cl-bindgen as a library is to look at its main
function found in
In it, cl-bindgen's default options are set, then passed to
to run the utility.