CHICKEN is a Scheme-to-C compiler supporting most of the language
features as defined in the Revised^5 Report on Scheme. CHICKEN
generates quite portable C code, and files compiled by it (including
itself) should work without any changes on most platforms.
The whole package is distributed under a BSD license and as such free
to use and modify as long as you adhere to its terms (see the manual).
Linkage to C modules and C-library functions is straightforward, so
it's easy to access C from Scheme. Compiled code can be embedded into
existing C programs without problems. The generated code supports
full tail-recursion, first-class continuations, multiple values and
dynamic-wind.
Changes since chicken-4.13.0:
5.0.0
-----
- Runtime system
- Added support for the full numeric tower, including various new
procedures taken from the "numbers" egg. All calculations will
now return exact numbers where possible, so code relying on flonums
being returned may need to be changed if rational numbers do not
provide the desired performance.
- Port directionality has been generalized from a simple input/output
flag to a bitmap, to allow for multidirectional ports.
- Weak symbol GC is faster, simpler, and can now collect all
unreferenced symbols instead of a maximum of 997 per major GC.
- The -:w option has been removed; symbols are now always collected.
- Increased the "binary compatibility version" to 9.
- Continuations which discard additional values beyond the first now
also accept multiple values via direct invocation after being
captured through `call/cc`, not just via `values` (#1390)
- Removed the deprecated C_locative_ref and C_mutate2 C functions.
- The trace buffer no longer holds on to thread objects, allowing them to
be garbage collected sooner (#1356, thanks to Kristian Lein-Mathisen)
- On Cygwin and MinGW, the "build-platform" now corresponds to the
tool chain used (gnu, clang, unknown) like on *nix, while the
software-version is now "cygwin" or "mingw32" instead of "unknown".
This also means the features list will now contain the tool chain
on all platforms.
- Symbols starting with #% are no longer treated specially and need
to be quoted with pipes. This makes the "%" sign available for use
in custom/user-defined sharp-sign read syntax.
- Compiler
- Fixed an off by one allocation problem in generated C code for (list ...).
- The "-scrutinize" compiler option has been removed.
- The "-module" compiler option (aliased as "-m") now expects a module name.
- The generated C output of the compiler is now deterministic: it
will be bit-for-bit identical when compiling the same Scheme file
with the same version of the compiler.
- the "-consult-type-file" and "-emit-type-file" options have been renamed
to "-consult-types-file" and "-emit-types-file", respectively.
- Tools
- The new "-link" option to csc allows linking with objects from extensions.
- The new "-libdir" option to csc allows overriding the runtime library
directory.
- The ambiguous "-l<libname>" option for csc has been removed (#1193).
- Removed deprecated "-n" shorthand for "-emit-inline-file" from csc.
- Removed "chicken-bug" tool.
- Core libraries
- Removed support for memory-mapped files (posix), queues
(data-structures), binary-search (data-structures), scan-input-lines
(utils), group-information (posix) object-eviction (lolevel), and
compile-file (utils). These are now available as eggs.
- Removed the srfi-1, srfi-13, srfi-14, srfi-18, srfi-69, and utils
units. These are now available as eggs.
- Added the `executable-pathname` procedure for retrieving a path to
the currently-running executable.
- Removed all support for SWIG.
- Removed interrupts-enabled declaration specifier.
- `sleep` now suspends the current thread when threading is enabled,
otherwise it sleeps the process. The new `process-sleep` procedure
in unit posix can be used to sleep the process unconditionally.
- `with-error-output-to-port' from the ports module has been renamed
to the more common `with-error-to-port', and `with-error-to-string'
has been added for completeness (thanks to Michael Silver).
- A new `make-bidirectional-port' procedure has been added to the
ports unit that will combine separate input- and output- ports into
a single bidirectional port.
- New `input-port-open?` and `output-port-open?` procedures have been
added for testing whether a port is open in a specific direction.
- An `include-relative` form has been added to the (chicken base) module.
This works like `load-relative` but for textual inclusion.
- Keywords are now always written in "portable" style by WRITE, so
that the reader's keyword style doesn't need to match the writer's.
- The environment variable `CHICKEN_PREFIX` has been removed.
- Added the `glob->sre` procedure to the irregex library.
- Removed the `get-host-name' and `system-information' procedures.
These are available in the "system-information" egg.
- Removed the `eval-when`, `select` and `ensure` macros. These are
available in the "miscmacros" egg.
- Removed the require-extension-for-syntax macro.
- Renamed bit-set? to bit->boolean because of swapped argument order
with respect to SRFI-33 and SRFI-60, which was confusing (fixes
#1385, thanks to Lemonboy).
- file-{read,write,execute}-access will now raise an exception when
the file doesn't exist or some other non-access related problem is
detected (fixes#1386, thanks to Vasilij Schneidermann).
- `change-file-mode` was renamed to set-file-permissions! and SRFI-17
generalized set! support has been added for `file-permissions`.
This procedure now also accepts a file descriptor or a port.
- `file-permissions` now returns one value: the permission integer.
- `read-file` has been renamed to `read-list`.
- `read-all` was dropped, as `read-string` with #f as its NUM argument
is equivalent.
- `read-lines` and `read-all` no longer accept a string naming a file,
only ports.
- The procedures for random numbers have been reimplemented;
access to system-specific entropy is available, together with a reasonably
good pseudo random number generator (WELL512).
- `glob` now returns an empty list for non-existent or inaccessible
directories, instead of erroring out.
- `file-copy' and `file-move' have been renamed to `copy-file' and
`move-file', for consistency with `delete-file' and `rename-file'.
- `rename-file' now refuses to overwrite an existing file unless an
optional "clobber" argument is provided.
- The `r4rs` module no longer exports `eval`, which was not in R4RS.
- `process`, `process*` and `process-execute` now expect lists of the form
(("NAME" . "VALUE") ...) instead of the previous (("NAME=VALUE") ...)
as their environment argument.
- `repository-path` is now a parameter containing a list of strings instead
of a string, as the search path for libraries can now contain multiple
directories.
- `file-read-access?`, `file-write-access?` and `file-execute-access?` have
been renamed `file-readable?`, `file-writable?` and `file-executable?`
into the (chicken file) module.
- Module system
- The compiler has been modularised, for improved namespacing. This
means names from the compiler should not leak out into the compiled
program's (macro) namespace anymore.
- The core units have been converted to modules under the "chicken"
namespace.
- Added support for list-style library names.
- The "use" and "use-for-syntax" special forms have been removed
in favor of "import" and "import-for-syntax" to reduce confusion.
- Module imports are now lexically scoped: identifiers provided by
an (import ...) inside (let ...) won't be visible outside that let.
- Modules implementing an interface can now correctly export extra
identifiers (bug reported by Martin Schneeweis, fix by "megane").
- Syntax expander
- Removed support for (define-syntax (foo e r c) ...), which was
undocumented and not officially supported anyway.
- Removed support for normal "lambda" forms as syntax transformers,
which has been deprecated since 4.8.0.
- define and friends are now aggressively rejected in "expression
contexts" (i.e., anywhere but toplevel or as internal defines).
- define-record and define-record-type now create record types
which are tagged with the module in which they're defined, so
predicates no longer return #t for records with the same tag
defined in another module. This tag is now also available under
an identifier that matches the record type name (fixes#1342).
- `include` now splices included expressions in the context in which
the inclusion appears and does not treat the expressions as toplevel
expressions by default.
- Eggs management
- Egg-installation and building has been completely overhauled.
- .meta + .setup files have been merged into a single declarative
".egg" file.
- More static checks for egg descriptions, simplified generation
of OS-specific build + install commands that is (hopefully)
more practical for package maintainers.
- Egg sources are cached locally to reduce download and rebuild
times.
- Dropped many obscure or unimportant options and features from
`chicken-install`: (`-keep-installed`, `-reinstall`, `-proxy`,
`-no-install`, `-username`, `-password`, `-init`, `-deploy`,
`-keep-going`, `-scan`, `-csi`, `-show-depends`, `-show-foreign-depends`,
`-prefix`.
- Added new "-from-list" option to chicken-install.
- Eggs can now be installed and located in multiple directories,
using the `CHICKEN_REPOSITORY_PATH` +
`CHICKEN_INSTALL_REPOSITORY`
environment variables.
- Static compilation of eggs is now fully supported and static
versions of compiled eggs are available by default.
- In a statically built chicken, the egg-tools ("chicken-install", "...-status",
"...-uninstall") are still available, but only support static compilation
of eggs.
- Foreign function interface
- The foreign type specifier "ssize_t" is now accepted, and "size_t"
arguments now only accept positive integers. Return values of
type size_t are no longer truncated on 32-bit platforms.
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