LispMe

LispMe is an implementation of R4RS Scheme for the Palm OS written by Fred Bayer. It is not exactly a strong Scheme implementation, but it is small enough to fit comfortably on a Palm handheld. If you want a powerful, full-featured scheme implementation, you have arrived at the wrong place: visit Scheme48, PLT-Scheme or one of the other Scheme-implementations instead. If you want a REPL for your pocket, this is the place to be. Also available is Pocket-Scheme for WinCE handhelds.

LispMe on the wiki

• See LispMe-language-elements for a comprehensive list of top-level vars, procedures and primitives.
• See bunny-test, a LispMe unit testing package.
• There is a LispMe-named-LET-fix for fixing its lack thereof (not necessary after 3.22).

The Good

Because it is written for Palm OS, you can carry around a Scheme interpreter in your pocket with any Palm OS compatible device.

Hey baby, is that a REPL in your pocket, or are you happy to see me!

Hack scheme on the train! In a queue to the club! In the bath! On the toilet!

It also provides you access to the Palm OS memos (text files) with the standard scheme I/O procedures.

LispMe does implement call-with-current-continuation (as call/cc -- can you imagine writing out call-with-current-continuation in graffiti?).

On top of the standard R4RS scheme, it provides the following features:

• access to VFS, HandDBase, Palm Resource, and Palm Database formats;
• access to the serial port (including IR port);
• access to the TCP/IP stack (if available);
• graphics operations (boxes, lines, fonts, bitmaps, palm 8x8 tiles); and
• it can load Resource Databases & manipulate UI elements

The Bad

LispMe does provide a macro system, but it has the following limitations:

• It is unhygienic. See hygiene-versus-gensym for more information.
• You cannot use macros on the top level.
• You can only define macros on the top level.
• The macros are executed in a different space of the VM. The implications of this mean:
  • You cannot interrupt the processing of a macro (by pressing the break button, or any of the palm hardware keys).
  • Macros have limited space & time with which to perform it's actions (to make sure an errant macro doesn't take over your palm).

Also, LispMe does not implement the full numeric tower: it lacks rational numbers.

The Ugly

• LispMe implements R4RS only, not R5RS.
• LispMe's eval accepts one argument; it evaluates the expression in the current environment only. It also cannot evaluate define or macro (top-level macro definition) forms.
• The top level of a loaded memo can contain only define and macro forms. Anything else is illegal. Goodbye modules, goodbye loading other dependencies.

category-implementations