picrin-scheme / picrin

lightweight scheme interpreter

The project is in hiatus and being archived soon...

Picrin is a lightweight R7RS scheme implementation written in pure C89. It contains a reasonably fast VM, an improved hygienic macro system, useful contribution libraries, and simple but powerful C interface.

• R7RS compatible
• Reentrant design (all VM states are stored in single global state object)
• Bytecode interpreter
• Direct threaded VM
• Internal representation by nan-boxing (available only on x64)
• Conservative call/cc implementation (VM stack and native c stack can interleave)
• Exact GC (simple mark and sweep, partially reference count)
• String representation by rope
• Hygienic macro transformers (syntactic closures, explicit and implicit renaming macros)
• Extended library syntax

Documentation

See http://picrin.readthedocs.org/

Homepage

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

https://github.com/picrin-scheme/picrin

Build

Just type make in the project root directory. You will find an executable binary newly created at bin/ directory.

$ make

When you are building picrin on x86_64 system, PIC_NAN_BOXING flag is automatically turned on (see include/picrin/config.h for detail).

Install

make install target is provided. By default it installs picrin binary into /usr/local/bin/.

$ make install

Since picrin does not use autoconf, if you want to specify the install directory, pass the custom path to make via command line argument.

$ make install prefix=/path/to/dir

Requirement

To build Picrin Scheme from source code, some external libraries are required:

• perl
• regex.h of POSIX.1
• libedit (optional)

Make command automatically turns on optional libraries if available. Picrin is mainly developed on Mac OS X and only tested on OS X or Ubuntu 14.04+. When you tried to run picrin on other platforms and found something was wrong with it, please send us an issue.

Authors

See AUTHORS

picrin's Issues

Wind exception handler from C function

export bug?

I'm writing SRFI-9 (Defining Record Types).
https://gist.github.com/stibear/8982207
If export "define-record-type" only,

compilation error: unbound variable define-record-field

So I wrote (export define-record-type define-record-field), though I didn't export define-record-field.

I think this is export's bug. What do you think?

user-defined reader macro

Related: #59

picrin logo

Any idea?

irep/pool gc

no `macroexpand`?

repl shows strange message?

According to @stibear, repl seems show some strange message when defining below function.

I expect this is caused by readline, but further research is required.

> (define (circular-list? x)
    (and (pair? x)
     (let rec ((lst (cdr x)))
       (cond ((not (pair? lst)) #f)
         ((null? lst) #f)
         ((eq? x lst) #t)
         (else (rec (cdr lst)))))))
* * * * 
.git/        .travis.yml  Makefile     etc/         lib/         t/
.gitignore   AUTHORS      README.md    extlib/      piclib/      tools/
.gitmodules  LICENSE      bin/         include/     src/         
* 
.git/        .travis.yml  Makefile     etc/         lib/         t/
.gitignore   AUTHORS      README.md    extlib/      piclib/      tools/
.gitmodules  LICENSE      bin/         include/     src/         
* 
.git/        .travis.yml  Makefile     etc/         lib/         t/
.gitignore   AUTHORS      README.md    extlib/      piclib/      tools/
.gitmodules  LICENSE      bin/         include/     src/         
compilation error: invalid expression given

import test cases from chibi scheme

optional arguments

I often want to define the function receiving optional arguments.
IMO, it is not necessary, but should be discussed.
How do you feel about it?

in-process debugger API

inter-referential definition support

In most practical cases interreferential definitions frequently occurs on the source code. Especially reference to undefined global function which will be defined later on the code appears many times.

compilation failure on Arch Linux

$ make
cd src; \
  yacc -d parse.y; \
  lex scan.l
parse.y: 30.1-12: 警告: deprecated directive, use `%pure-parser` [-Wdeprecated] %pure_parser
 ^^^^^^^^^^^^^
flex: Can't use --reentrant or --bison-bridge with -l option
Makefile:24:  recipe for target 'build-lib' failed
$

$ lex --version
2.5.37
$ yacc --version
bison 3.0

object arena handler stack

Unlike mruby picrin create a number of objects in one call (mainly because of the existence of cons). We need another way to manage newly allocated objects in c function just as Rubinius does.

native let support

(scheme lazy) bug

https://gist.github.com/stibear/9159923
force's bug?

Core dump from REPL

Hi,

I just pulled picrin source from the repo, and after issuing these in REPL:

> (define (range s e) 
     (if (>= s e) 
       (list)
       (cons s (range (+ 1 s) e))))
> (apply + (range 1 10000))

I'm getting core dump. Any idea what can be wrong?

Best, Sanel

Error on compiling picrin on Debian 6.0.6

It looks like linking process fails due to undefined references.
Operating System: Debian GNU/Linux 6.0.6
Error Message: https://gist.github.com/koba-e964/9bf1248eeec258d495b4

and is behaving incorrectly

> (and (number? 10) (* 10 10))
=> #t

I expect it returns '100' but '#t'

variable-length instruction form

regex support

Possible API design:

• (regex ptrn [flags])
• (regex-match re txt)
• (regex-search re txt)
• (regex-replace re txt)
• (regex-split re txt)
• reader syntax: #/.../[gi]

Escape sequences in string literal does not work

bug in explicit renaming?

I defined hygenic and macro as below, but picrin crashes while expanding this macro. It seems that (rename 'if) in last line cause this bug.

;; crash
(define-syntax myand
  (er-macro-transformer
   (lambda (form rename compare)
     (let ((exprs (cdr form)))
       (if (null? exprs)
       #t
       (let ((test (car exprs))
         (if-true (cons (rename 'myand) (cdr exprs))))
         (list (rename 'if) test if-true  #f)))))))

;; work
(define-syntax badand
  (er-macro-transformer
   (lambda (form rename compare)
     (let ((exprs (cdr form)))
       (if (null? exprs)
       #t
       (let ((test (car exprs))
         (if-true (cons (rename 'badand) (cdr exprs))))
         (list if test if-true  #f)))))))

need version information

TODO

• picrin --version
• add picrin-version to features
• create git tag

compilation error on circular-list?

According to @stibear below code does not work on picrin.

(define (circular-list? x)
    (let rec ((lst (cdr x)))
      (cond ((null? lst) #f)
        ((eq? x lst) #t)
        (else (rec (cdr lst))))))
; * * * * compilation error: invalid expression given

add write barrier

compilation error on Arch Linux

$ make
cd src; \
  yacc -d parse.y; \
  flex scan.l
gcc -Wall -g -DDEBUG=1 -O0 -shared src/*.c -o lib/libpicrin.so -I./include -I./extlib -lm
In file included from scan.l:6:0:
y.tab.h:113:21: warning: ‘struct parser_control’ declared inside parameter list [enabled by default]
y.tab.h:113:21: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
/usr/bin/ld: /tmp/ccVEtfJs.o: relocation R_X86_64_32 against `.rodata' can not be used when making a shared object; recompile with -fPIC
/tmp/ccVEtfJs.o: could not read symbols: Bad value
collect2: error: ld returned 1 exit status
Makefile:24: recipe for target 'build-lib' failed
make: *** [build-lib] Error 

native multiple value support

depends on #15

change calling convention between codegen and macroexpand

call macroexpand incrementally in the codegen phase, not expand all macros before the codegen.

cons*がruntime errorする

bin/picrin
> (define (append-reverse rev-head tail)
    (append (reverse rev-head) tail))
* => #f
> (define (cons* x . args)
    (let rec ((acm '()) (x x) (lst args))
      (if (null? lst)
          (append-reverse acm x)
          (rec (cons x acm) (car lst) (cdr lst)))))
* * * * => #f
> (cons* 1)
=> 1
> (cons* 1 2 3 4)
runtime error: invalid application

`(error obj)` causes segv when no exepction handler is stacked

$ make run
bin/picrin
> (error "my error")
make: *** [run] Segmentation fault: 11

Bug in `load`

If non-existent library was imported in define-library, symbols which are already bound become unbound.

../test.scm:

(define-library (dummy 0)
    (import (wwq))
)

input and output:

koba-e964@debian-koba-e964-0:~/srcview/picrin$ bin/picrin 
> (+ 2 3)
=> 5
> (import (scheme load))
=> #f
> (load "../test.scm")
=> #<undef>
> (+ 2 3)
error: unbound variable +
> (list 2 3)
error: unbound variable list
> 
koba-e964@debian-koba-e964-0:~/srcview/picrin$ 

swank-picrin (slime backend for picrin)

To make slime backend we first need add in-process debugging API to picrin.

https://github.com/cj2tszk/swank-gauche

er-macro-transformer is broken

Likewise Chibi-scheme, we've currently made use of syntactic closures to implement er/ir-macro-transformer. I however found they are broken because they require identifier? and identifier=? are defined in global scope. In the original algorithm of er/ir-macro, the transformers don't require any helper functions declared, and instead they close all syntactic information in rename and compare functions which will be passed to the transformer.

pritty print for record type

lf defining a record type, print like this (https://gist.github.com/stibear/9074533).
You can get the record name by using (vector-ref (vector-ref record-object 1) 2).

Fail to import srfi-1

> (import (srfi 1))
compilation error: library not found

rewrite parser

obsolete yacc

auto stack extend

way to get backtrace?

hygiene problem

Per justinethier/husk-scheme#151 the expression

(let ((unquote 'foo)) `(,'bar)

should expand into (,'bar) or ((unquote (quote bar))). But instead it expands into (bar):

justin@justin-desktop:~/Documents/picrin$ make run
bin/picrin
> (let ((unquote 'foo)) `(,'bar))
=> (bar)

add a library-embedding tool like mrbc in mruby

It would be better if we have a tool to embed the built-in library in libpicrin. mruby already includes such tool, called mrbc. I saw a similar approach in V8 (but it might have changed now).

AFAIK mruby choose byte code as embedding format and V8 did JavaScript source code. Which is better for us?

nested unhygienic macros broken

According to @zeptometer, macroexpander seems broken when unhygienic macros are complicatedly nested

https://gist.github.com/zeptometer/8885494

(destructuring-bind ((a b) . c) '((1 2) 3 4 5) (list a b c))

; expands to

((lambda (evaluated@605)
   ((lambda (evaluated@605)
      ((lambda (a@617)
     (begin ((lambda (evaluated@605)
           ((lambda (b@619)
              (begin
            (begin
              ((lambda (c@620) (begin (list@19 a@617 b@619 c@620)))
               (cdr@9 evaluated@605)))))
            (car@8 evaluated@605)))
         (cdr@9 evaluated@605))))
       (car@8 evaluated@605)))
    (car@8 evaluated@605)))
 (quote ((1 2) 3 4 5)))

A variable evaluated is expanded in a uniform symbol but theoretically must be compiled to each different symbols.

evaluating circular list should emit an compile error

immutable string by default, use `transient-string` to modify strings efficiently

pattern match

Many scheme implementations have pattern matching library.
I think it is necessary for picrin also and if so, how should it be implemented?

For reference,

Andrew Wright's pattern matching system (pdf)
http://download.plt-scheme.org/doc/103p1/pdf/match.pdf

`write` should not use datum labels on non-circular objects.

turn on -Wextra flag

unicode support

not working on windows

partial continuation support

`list?` should stop when a circular list is given

According to the draft r7rs.pdf, list is define as the smallest set of proper list which has finite length.