Picrin is a lightweight scheme implementation intended to comply with full R7RS specification. Its code is written in pure C99 and does not requires any special external libraries installed on the platform.

• R7RS compatibility (but partial support)
• reentrant design (all VM states are stored in single global state object)
• bytecode interpreter (based on stack VM)
• direct threaded VM
• internal representation by nan-boxing
• conservative call/cc implementation (users can freely interleave native stack with VM stack)
• exact GC (simple mark and sweep, partially reference count is used as well)
• string representation by rope data structure
• support full set hygienic macro transformers, including implicit renaming macros
• extended library syntax
• advanced REPL support (multi-line input, etc)
• tiny & portable library (all functions will be in libpicrin.so)

- `(scheme base)`
- `(scheme write)`
- `(scheme cxr)`
- `(scheme file)`
- `(scheme inexact)`
- `(scheme time)`
- `(scheme process-context)`
- `(scheme load)`
- `(scheme lazy)`
- `(picrin macro)`

    - `define-macro`
    - `gensym`
    - `macroexpand`

        Old-fashioned macro.

    - `make-syntactic-closure`
    - `identifier?`
    - `identifier=?`

        Syntactic closures.

    - `er-macro-transformer`
    - `ir-macro-transformer`

        Explicit renaming macro family.

- `(picrin regexp)`

    - `(regexp? obj)`
    - `(regexp ptrn [flags])`

        Compiles pattern string into a regexp object. A string `flags` may contain any of #\g, #\i, #\m.

    - `(regexp-match re input)`

        Returns two values: a list of match strings, and a list of match indeces.

    - `(regexp-replace re input txt)`
    - `(regexp-split re input)`

- `(picrin control)`

    - `(reset h)`
    - `(shift k)`

        delimited control operators

- `(picrin user)`

	When you start the REPL, you are dropped into here.

- `(srfi 1)`

    List manipulation library.

- `(srfi 95)`

    Sorting and Marging.

At the REPL start-up time, some usuful built-in libraries listed below will be automatically imported.

• (scheme base)
• (scheme load)
• (scheme process-context)
• (scheme write)
• (scheme file)
• (scheme inexact)
• (scheme cxr)
• (scheme lazy)
• (scheme time)

1. Picrin provides hygienic macros in addition to so-called legacy macro (define-macro), such as syntactic closure, explicit renaming macro, and implicit renaming macro. As of now let-syntax and letrec-syntax are not provided.

Currently picrin is hosted on Github. You can freely send a bug report or pull-request, and fork the repository.

https://github.com/wasabiz/picrin

There is a chat room on chat.freenode.org, channel #picrin.

• make Makefile

  Change directory to build then run cmake to create Makefile. Once Makefile is generated you can run make command to build picrin.

    $ cd build
    $ cmake ..
  

  Actually you don't necessarily need to move to build directory before running cmake (in that case $ cmake .), but I strongly recommend to follow above instruction.

• build

  A built executable binary will be under bin/ directory and shared libraries under lib/.

    $ make
  

  If you are building picrin on other systems than x86_64, PIC_NAN_BOXING flag is automatically turned on (see include/picrin/config.h for detail).

• install

  Just running make install, picrin library, headers, and runtime binary are install on your system, by default into /usr/local directory. You can change this value via ccmake.

    $ make install
  

• run

  Before installing picrin, you can try picrin without breaking any of your system. Simply directly run the binary bin/picrin from terminal, or you can use make to execute it like this.

    $ make run
  

• debug run

  If you execute cmake with debug flag -DCMAKE_BUILD_TYPE=Debug, it builds the binary with all debug flags enabled (PIC_GC_STRESS, VM_DEBUG, DEBUG).

    $ cmake -DCMAKE_BUILD_TYPE=Debug ..
  

Picrin scheme depends on some external libraries to build the binary:

• perl
• lex (preferably, flex)
• getopt
• readline (optional)
• regex.h of POSIX.1 (optional)

Optional libraries are, if cmake detected them, automatically enabled. The compilation is tested only on Mac OSX and Ubuntu. I think (or hope) it'll be ok to compile and run on other operating systems such as Arch or Windows, but I don't guarantee :(

See AUTHORS