TinyLISP is LISP interpreter written in Forth based on Dieter Müller's book "LISP - An elementary introduction to the programming of non-numerical tasks", which I originally developed in 1988 on the Commodore 128 under CP/M 3.0 using the Forth 83 implementation F83 by Henry Laxen and Mike Perry.
It's a hobby project that I occasionally continue to work on under Gforth, though trying to maintain F83 compatibility for nostalgic reasons.
The LISP interpreter is started executing the Forth word driver after loading
the main source file tlisp.fs.
gforth -e "warnings off" tlisp.fs -e "driver"At startup, TLISP loads the file tlisp.lsp and enters the REPL.
Note
If warnings are enabled, Gforth will complain about entering double-cell integers without using a base-prefix, which is done for compatibility reasons.
Typing (EXIT) at the REPL exits both TLISP and Forth.
tlisp> (exit)
The behavior of TLISP can be changed at runtime by changing the desired property value of the CONFIG symbol, see the following table:
| Indicator | Description | Default |
|---|---|---|
| APVAL | Evaluate APVAL before/after the a-list | NIL |
| DEBUG | Enable/disable tracing | NIL |
| ECHO | Enable/disable echoing | NIL |
| EVALQUOTE | Enter/leave evalquote mode | NIL |
| EXIT | Exit Forth when exiting TLISP on/off | T |
| GC | Enable/disable garbage collection | T |
| PAUSE | Enable/disable single step execution | NIL |
There are two shortcuts DEBUG and ECHO predefined in tlisp.lsp
for the corresponding settings.
Changing the value of the setting EVALQUOTE to T enters evalquote mode and
changing it back to NIL returns to normal mode using eval:
tlisp> (putprop 'config t 'evalquote)
T
evalquote> caddr ((first second third fourth))
THIRD
evalquote> putprop (config nil evalquote)
NIL
tlisp>
- The length of a line is limited to 80 characters (
tlen) for historical reasons.
If a symbol overlaps this boundary, then it is silently separated at this point and two symbols are created.