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# Chicanery: subtle, opinionated improvements to R7RS Scheme
While I was reading the [R7RS
specification](https://standards.scheme.org/official/r7rs.pdf), I was a little
annoyed by how broken up the standard library seemed to be. While the most
egregious example is maybe `(scheme case-lambda)`, which exports ... only
`case-lambda`, the other libraries like `(scheme write)` for `display`, `(scheme
cxr)` for functions like `caddr` but not `cddr`, and the rest didn't really seem
logical to me. Plus, in CHICKEN scheme, the one I usually use, `utf8` is an egg
you need to install separately...
To ameliorate these minor warts in what I otherwise consider to be an excellent
language, `chicanery` was born. It's kind of like a prelude, I suppose? It
imports all `r7rs` modules and re-exports their identifiers, and makes sure the
implementation is Unicode-aware. It also includes a few extras ;)
## Chicanery extras
I also thought it was strange that `map`, `for-each`, and `append` apply to
lists only, while `vector-map` and `string-for-each`, exist, for example.
`chicanery` prefixes the default `map`, `for-each`, and `append` functions with
`list-`, and redefines those identifiers to functions that are generic over
Scheme's base collection types (lists, strings, vectors, bytevectors where
applicable). I didn't make the functions fully-generic to keep them efficient
and because I don't know how to do that, but you can still use `vector-append`
or `list-map` if you know what type you need and want speed.
In a similar vein, I've also added generic functions `ref` and `copy` that
dispatch to `string-ref`, `list-copy`, and the like.
Other extras include
- `(atom? x)` determines whether `x` is an atom (i.e., not a pair or null)
- `(read-port)`, `(read-port port)` reads a port until hitting end-of-file (IDK
why this isn't in R7RS!), in chunks of `read-port-chunk-size`
- `(defined? x)` returns whether the symbol `x` is bound to a variable
- `(displayed x)`, `(->string x)` returns `x` as a string (via `display`)
- `(written x)` returns `x` as a string (via `write`)
- `(print x ...)` displays `x ...` followed by a newline
## Supported Scheme implementations
`chicanery` now supports multiple R7RS implementations! The full list can be
found by running `make`, but here's what we have right now:
- [Chicken](https://call-cc.org/)
- [Guile](https://www.gnu.org/software/guile/)
- [Gambit](https://gambitscheme.org/)
- [Chibi](https://synthcode.com/scheme/chibi)
Other Scheme implementations have been minimally tested and I haven't been able to figure them out yet. However, [Cyclone](https://justinethier.github.io/cyclone/) is definitively *not* compatible; see [issue #413](https://github.com/justinethier/cyclone/issues/413).
## License
This software is licensed under the GWL, v. 1.0. See COPYING for details.
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