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Experimental fork of, primarily for keyword args and generic functions
Arc Scheme Perl
Branch: master

stop pretending that this is production-ready

blurb on github used to be: My curated set of patches atop
now it's: Experimental fork of, primarily for keyword args and generic functions
latest commit e34797317a
@akkartik authored
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Readme stop pretending that this is production-ready
ac.scm now support nested optionals and keywords -- only in a single destruc…
ac.scm.t Now walk can take a keyword!
app.arc crlf in http headers as required by rfc
blog.arc arc3.1
brackets.scm arc3.1
code.arc Now walk can take a keyword!
copyright arc3.1
html.arc support for multipart forms and file upload
libs.arc map, reduce, etc. can now handle trees
news.arc .
pprint.arc done converting other arc files to new optional-arg syntax. Arc loads up
prompt.arc undo previous; we need some one-character way to concatenate. 'join' …
queue.arc merge defgeneric and 'extend' into defextend
services.arc .
spliceable-list.arc merge defgeneric and 'extend' into defextend
state.arc .
tree.arc Now walk can take a keyword!


An experimental and incompatible fork of the Arc programming language (

*Important*: If you are running a HN-like site, using this fork will mess up
your data. Talk to me first, and be sure to make a backup.

- Features so far
'$' for escaping to scheme for making scheme extensible from arc
Dynamic scope:

Extensible coerce (rntz;
Macros can be defined in any order.

All functions are generic and can be extended for new conditions
using 'defextend'.
  (Previous discussions:,,

pervasive keyword args. If a function f has params (a b c), (f :c 3 1 2) <=> (f 1 2 3), etc.
BUT this assumes no keyword syms in data:
  arc> (iso :x :x)  # won't work because x is a param of iso

new arglist syntax:
  arc> (def foo (a ? b 34) (list a b))
  arc> (foo 3)
  (3 34)

optional params and keyword args can't be combined with destructuring.

transparent persistence using 'persisted', which can be extended for new
datatypes by supporting the generics 'serialize' and 'unserialize'.

  parse IP from X-Forwarded-For
  access static subdirectories
  more mime-types, more html attributes, more useful logging
  correctly sends crlf-terminated lines

  readline handles empty lines:,
  downcase/upcase on nil return nil:
  each over tables returns nil

Case can work on lists and other compounds

- Incompatibilities and gotchas
0. temload and temstore are subtly different. If you've been using news.arc
on your own site, make a backup before switching.
1. nil == (); type.nil == nil.
2. Optional args have a new syntax. (a (o b) (o c 3)) => (a ? b nil c 3)
3. some and keep don't testify.
4. Always handle null values when defining a generic
5. srv no longer calls setuid. Run it behind apache or nginx, never as root.
6. thread and new-thread require docstrings, like in autosave-thread in state.arc.
7. case no longer autoquotes:
8. List operations treat non-lists as degenerate dotted lists by default.
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