Changelog

0.9.2 - TBD

Features

• During CPS optimization allow inlining of operations on global variables that are mutated in other top-level functions.
• Improved loop detection during CPS optimization phase.
• Allow optimizing-out of basic if expressions of the form (if (pred? ...) #t #f) into (pred? ...).
• Perform slightly faster type checking for string, vector, and bytevector access functions.

Bug Fixes

0.9.1 - August 9, 2018

Bug Fixes

• Fixed a nasty bug where, while a mutator is blocked after calling set_thread_blocked, the collector may copy an object the mutator is using from the stack to the heap. In this case we need to ensure the object is not corrupted when it is copied and that we sync the object's fields back up once the mutator is unblocked. Currently this only affects port objects in the runtime. Generally read was affected more than other I/O functions.
• Fixed a handful of small garbage collection bugs from the previous round of development.

0.9 - July 31, 2018

This release significantly improves garbage collection performance by using lazy sweeping.

0.8.1 - July 2, 2018

Features

• Improved garbage collector performance for large heaps.
• Generate faster compiled code for:
  • car, cdr, and most built-in predicates.
  • Calls to list that contain less than five arguments.
  • Calls to map and for-each that only pass a single list.
• Allow optimization of some simple self-recursive functions.
• Allow the optimizer to beta expand a wider range of function calls.

Bug Fixes

• Fixed a bug where current-jiffy was returning total clock time of the process. Such an approach cannot be used to measure time accurately when more than one thread is executing concurrently.
• Prevent the possibility of an infinite loop by not beta expanding recursive function calls.

0.8 - May 30, 2018

Features

• Added support for complex numbers.
• When printing intermediate forms during debugging via -t Cyclone will now emit less verbose S-expressions for code in CPS form. To support this effort and make debugging easier, added helper functions ast:ast->sexp, ast:sexp->ast, and ast:ast->pp-sexp to (scheme cyclone ast).
• Avoid inlining function calls into named let loops to improve performance of compiled code.

0.7.3 - May 7, 2018

Features

• Made several performance improvements to SRFI 69 hash tables, including:
  • Massively improved lookup performance for symbols.
  • Increased the max bound of hash tables to (2 ^ 30) - 1.
  • Changed hash-by-identity to a high-performance builtin.
• Added a repl function to (scheme repl) to make it easy to use a REPL from your own code.
• Added basic support for square and curly brackets in place of parentheses.

Bug Fixes

• Fixed an off-by-one error in read-line where the function erroneously reported an extra character was read from stdin. Thanks to wasamasa for the bug report.
• Fixed a CPS optimization issue where multiple copies of the same lambda are introduced during beta expansion, which causes the optimizer to potentially pick up the wrong value when optimizing-out function calls later on. Thanks to on Github for providing the report and a test program demonstrating the issue.
• Updated the parser to recognize mnemonic escapes (EG: \n, \a, etc) and inline hex escapes as part of a symbol.

0.7.2 - February 15, 2018

Features

• Added a (scheme cyclone match) library based on Alex Shinn's match.scm portable hygienic pattern matcher.
• The compiler now emits a faster version of apply in cases where only two arguments are received.

Bug Fixes

• Made several improvements to macro hygiene by renaming local variable bindings during expansion. Added a unit test module covering many test cases.
• Fixed many functions including utf8->string, string->utf8, bytevector-copy, list->vector, and list->string to heap allocate objects that exceed the maximum size for objects on the stack.
• Prevent a compiler error when there is only one argument to + or *.

0.7.1 - December 21, 2017

Features

• Added support for let-syntax and letrec-syntax.
• Added the (scheme repl) library and interaction-environment function from R7RS.
• Allow eval to recognize syntax-rules macros.
• Added single-byte oriented I/O functions read-u8, peek-u8, and write-u8 from R7RS.

Internal Changes

• Relocated all macro expansion code to the (scheme eval) module. Cyclone's (scheme cyclone macros) library is now obsolete.

Bug Fixes

• Added the full-unicode feature since Unicode is supported as of the 0.7 release.

0.7 - November 17, 2017

Features

• Finally added Unicode support using UTF-8!
• Allow a program to have macros expand into a top-level import expression.
• Added continuous integration support thanks to Alex Arslan.

Bug Fixes

• Incorporated a patch from 0-8-15 to pass seconds to thread-sleep! instead of milliseconds. Fractional seconds are accepted as well for high-resolution timers.

0.6.3 - September 16, 2017

Features

• Allow the compiler to optimize calls to +, -, *, and / that accept more than 2 arguments.
• Added support for bignums to bitwise-if from SRFI 60.

Bug Fixes

• Fix read-line to remove trailing carriage return and/or newline characters. Thanks to wasamasa for the bug report!
• String ports created by open-input-string returned an extra garbage byte. This has been fixed by a patch from wasamasa.
• Prevent segfaults when allocating large strings using make-string.
• Added a fix from wasamasa to escape double quotation marks in strings when output via write.
• wasamasa patched read-string to return EOF when no characters can be read.

0.6.2 - August 25, 2017

Features

• Made additional speed increases to read.
• Streamlined type checking to make the remainder function faster.
• Relocated string-join to (scheme cyclone util) and added a corresponding string-split function.
• Allow optimization of define-c functions marked as inline even if an alternative non-CPS version of the function is not defined.

Bug Fixes

• Prevent the possibility of segmentation faults when working with large vectors. When a vector is large enough it is allocated directly on the heap, but prior to this fix it was possible that any vector elements on the stack were not moved to the heap during minor GC. This then opens up the possibility of memory corruption when any of those elements are modified, including marking by the runtime's GC.

0.6.1 - August 22, 2017

Bug Fixes

• Fixed regression: there was the possibility of crashing when calling close-port.

0.6 - August 21, 2017

Features

• Added a faster version of read.
• Added SRFI 143 - Fixnums.

Bug Fixes

• Prevent remainder from crashing the runtime due to divide by zero.
• Avoid printing an unnecessary colon after certain error messages.

0.5.4 - August 3, 2017

Features

• Allow the -A and -I options to icyc for specifying additional library import directories.
• Perform constant folding as part of the CPS optimization phase.
• Statically allocate closures that do not contain any free variables, to avoid unnecessary heap allocations.

Bug Fixes

• Updated string->number to return #f for all bases when the conversion fails. Previously bases other than ten would return 0 instead.

0.5.3 - June 29, 2017

Features

• On Arthur Maciel's suggestion, modified Cyclone to always check its system folder for a library if an import is not found. In conjunction with this, the CYCLONE_LIBRARY_PATH environment variable may be set to force Cyclone to look in a specific place other than the system folder for libraries.
• Decrease minor GC time by only tracing globals when one of them has changed.
• Added the thread-join! function to (srfi 18).

0.5.2 - June 5, 2017

Bug Fixes

• Fixed a bug in for-each that was causing length to be executed during each iteration.

0.5.1 - May 24, 2017

The main focus of 0.5.1 is performance but this is also the first release to provide installation instructions for both Windows and Mac.

Features

• Thanks to Kashyap for adding build instructions for Windows (MSYS) and Mac!
• Allow define-c function definitions to optionally provide an additional non-CPS form of the function. This form is more efficient and will be used by compiled code whenever possible.
• Improved the compiler's CPS optimization phase to eliminate more unnecessary function calls.
• Modified the GC to allow a given number of "huge" allocations to trigger GC. Previously GC was only triggered when smaller heap regions were below a certain percentage of free memory.
• Compiled code now directly accesses boxed mutable variables instead of using a wrapper function.
• Added command line options to icyc for evaluating an S-expression from the command line and for running as a script without the Cyclone banner text.

Bug Fixes

• Prevent potential memory corruption when working with large vectors that cannot be allocated on the stack.

0.5 - April 14, 2017

Features

• Cyclone now has support in the interpreter for loading libraries via import. This is probably the most important change in this release and allows icyc to be used to its full potential.

• Store parameter objects in such a way that changes to a parameter object do not affect other threads that use the same parameter object.

  The specific requirement from R⁷RS is:

  > parameterize must not change the associated values of any parameters in any thread other than the current thread and threads created inside the parameterize body.

• Added bignum support to SRFI 60 - integers as bits.
• Normalize the result of string->number such that bignums are only returned if the result truly is a bignum.
• Allow Cyclone to find (cyclone) prefixed libraries installed in Cyclone's system folder.
• Allow a library to export identifiers that are exported by another library. Previously a library could only export identifiers that it defined directly.
• Raise an error if an unknown identifier is found in a library's export list.
• Aric Belsito removed a hardcoded call to cyclone from the Makefile when building generate-c. Thanks!
• Allow cyclone to inline character comparison functions (char=?, etc) when only two arguments are present, for a significant speed improvement.

Bug Fixes

• Prevent exception handlers from being accidentally collected when the collector cooperates on behalf of a mutator.
• Fixed a regression where string->number returns 0 on bad input instead of #f.

0.4 - March 9, 2017

• Added a new bignum type to support exact integers of practically unlimited size.
• As part of the bignum changes, modified the code for exact integer arithmetic to detect overflow.
• Added documentation for the C API.

0.3.4 - February 10, 2017

Features

• Koz Ross added implementations of the following SRFI's:
  • SRFI 28 - Basic format strings
  • SRFI 60 - Integers as bits
  • SRFI 121 - Generators
• Allow a program to have more than one import declaration. A program can now also use cond-expand to selectively expand import declarations.
• Added the -A and -I compiler options from SRFI 138 to cyclone:

-A directory

Append directory to the list of directories that are searched in order to locate imported libraries.

-I directory

Prepend directory to the list of directories that are searched in order to locate imported libraries.

• Added the -CP, -CE, and -CL compiler options to allow passing arbitrary flags to the C compiler:

-CP cc-commands

Specify a custom command line for the C compiler to compile a program module. See Makefile.config for an example of how to construct such a command line.

-CE cc-commands

Specify a custom command line for the C compiler to compile an executable.

-CL cc-commands

Specify a custom command line for the C compiler to compile a library module.

• Updated the garbage collector to enhance performance for programs with a high allocation rate, and to scale better to multiple concurrent threads.
• Improved error handling by display and write.
• Removed the make_int C macro which was deprecated and could cause problems when used in FFI functions.
• Added a with-handler exception handler form based on the syntax from Bigloo.

Bug Fixes

• Thanks to Koz Ross, equal? has been updated to check bytevectors for deep equality.
• Prevent crashes when allocating large bytevectors.
• Display characters such as #\space correctly when output via write.
• Thanks to Seth Alves, removed unnecessary include of ck_string.h which is not provided in older versions of libck.

0.3.3 - December 19, 2016

Features:

• Added SRFI 113 - sets and bags.
• Improved performance by more aggressively inlining primitives that work with immutable objects, such as the numeric arithmetic and comparison functions.
• Allow the reader to recognize #true and #false.

Bug Fixes

• Prevent C compilation errors when compiling strings with special characters in them such as #\tab, #\alarm, and #\return.
• Do not generate invalid C code when compiling + or * without any arguments.
• Handle compilation of variable-argument anonymous lambdas. For example: ((lambda x x) 3 5).

0.3.2 - November 22, 2016

Features:

• Recognize escaped vertical line and hex scalar value characters when reading a string.
• Added current-thread to SRFI 18.
• Added the include and include-ci macros.

Bug Fixes

• Fixed a crash when running cyclone on 32-bit platforms.

0.3.1 - November 20, 2016

Features:

• Thanks to ecraven, added R7RS function exact-integer-sqrt to (scheme base).
• Allow the reader to recognize +inf.0, -inf.0, +nan.0, and -nan.0.
• Allow cond-expand to test for whether a library exists using the form (library {library name}).
• Added command line option -O to set the optimization level. For now there is -O0 to disable optimizations and the default setting to enable them. Going forward there will be more fine-grained control.
• Reduce size of compiled code by inlining constant values. This reduced the code size of various cyclone libraries by approximately 33%. Added other inlining as well to slightly improve performance.
• Increased allocation speed when objects are moved to the heap during a major GC.

Bug Fixes

• Only throw a divide by zero error for integer division. Floating point divide by zero is allowed and evaluates to nan.
• Modified SRFI 106 to be smarter about compiling AI_V4MAPPED and AI_ALL, which are not defined on OpenBSD.
• Fixed the member functions to always return the list when a value is found, instead of #t.
• Fixed string->number to return #f if the string cannot be converted.
• Fixed a bug where the optimizer would sometimes generate incorrect code when a mutating primitive (EG: set-car!) was passed an expression rather than an identifier as the variable argument.
• Prevent the runtime from crashing when a non-numeric value type is passed to a numeric function.

0.3 - October 22, 2016

Features:

• Improve performance by inlining numeric arithmetic and comparison operations.
• Reverted assq, assv, memq, and memv back to primitives for improved performance. In addition the compiler was modified to allow for more efficient compilation of assoc and member.
• Improved library support to recognize all of the import set forms: only, except, prefix, and rename.
• Allow explicit renaming macros to be declared interactively. This is the first limited support for calling define-syntax from eval.
• Added the get-environment-variables function from R7RS.
• Added support for the following SRFI's:
  • SRFI 106: A basic socket interface
  • SRFI 128: Comparators

Bug Fixes

• Improved macro hygiene support to properly rename temporary variables in the let-values macro.
• Improve output of error by using write to output objects as they are represented in memory.
• Check for duplicate lambda parameters during compilation.
• Fixed an error that was being raised when calling (random-source-randomize! default-random-source) when using SRFI 27.
• Raise an error if list->string encounters a list element that is not a character.

0.2 - September 7, 2016

Features:

• Added the following libraries from R7RS-large red edition (data structures):
  • SRFI 1 list library
  • SRFI 133 vector library
  • SRFI 111 boxes
  • SRFI 117 mutable queues
  • SRFI 132 sorting library
• Added SRFI 2, and-let*
• Added parameterize from section 4.2.6 of R7RS to the (scheme base) library.
• Added let-values and let*-values to (scheme base).
• Added infinite?, finite?, and nan? to (scheme inexact).
• Added string ports to (scheme base) - open-input-string, open-output-string, and get-output-string.
• Added bytevector ports to (scheme base) - get-output-bytevector, open-input-bytevector, and open-output-bytevector.
• Modified cyclone to also search the current working directory for built-in headers and libraries.

Bug Fixes:

• Thanks to Mark Meyer, identified and fixed several segfaults in write and display.
• Updated write to display escaped character sequences (EG: \t) instead of literal characters.
• Prevent C compilation errors when building a program that only contains basic primitives or a constant at the top level.
• Fixed the compiler to allow application of a function that can take any number of arguments. For example:

     ((lambda test (write test)) 1 2 3 4)
  

• Updated eval to handle functions that take an optional number of arguments.
• Updated number->string to omit leading zeros for binary conversions.
• Fixed apply to use the proper semantics when receiving more than one data argument.
• Changed the assoc and member functions to accept an optional comparison function, and modified both families of functions to be native Scheme functions instead of C primitives.
• Allow libraries to contain multiple import, begin, and export sections.