reach fibonacci function; document

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NunoSempere 2023-05-10 11:03:36 -04:00
parent edbd51b450
commit e15cb4e3aa
3 changed files with 20 additions and 7 deletions

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@ -2,7 +2,7 @@
## About
This is a Lisp written in C. It follows the outline in this [Build Your Own Lisp](https://buildyourownlisp.com/chapter11_variables) book, though it then adds some small tweaks and improvements and quality of life improvements:
This is a Lisp written in C. It follows the outline in this [Build Your Own Lisp](https://buildyourownlisp.com) book, though it then adds some small tweaks and improvements and quality of life improvements:
- A makefile
- Configurable verbosity levels
@ -68,28 +68,32 @@ mumble> join { {1 2} {3 4} }
mumble> def {x} { 100 }
mumble> def {y} 100
mumble> (x y)
mumble> VERBOSITY=0
mumble> VERBOSITY=1
mumble> VERBOSITY=2
mumble> def {sq} (@ {x} {* x x})
mumble> sq 44
mumble> VERBOSITY=1
mumble> def {sqsum} (@ {x y} {(+ (sq x) (sq y))})
mumble> sqsum 2 3
mumble> VERBOSITY=0
mumble> def {init} (@ {xs} { list((head xs)) } )
mumble> def {unwrap} (@ {x} { head (list xx) } )
mumble> init {1 2}
mumble> ifelse 1 2 3
mumble> ifelse 0 1 2
mumble> ifelse {1 2 3} (1) (1)
mumble> def {positive} (@ {x} {> x 0})
mumble> def {fibtest} (@ {x} {if (> x 0) {+ x 1} 0 })
mumble> fibtest 2
mumble> def {fibonacci} (@ {x} {if (> x 1) { + (fibonacci (- x 2)) ( fibonacci ( - x 1 ) ) } 1} )
mumble> fibonacci 4
```
## To do
- [x] Define functions
- [ ] Define if, = and >
- [ ] Build fibonacci function
- Should look something like: def {fib} (@ {x} { ifelse x (+ x (fib (- x 1))) 0 } )
- [x] Define if, = and >
- [x] Build fibonacci function
## Gotchas
This doesn't currently run on Windows. But it easily could, with [preprocessor statements from the book].
This doesn't currently run on Windows. But it easily could, with the preprocessor staments from parsing.c [here](https://buildyourownlisp.com/chapter6_parsing).

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@ -847,9 +847,18 @@ lispval* builtin_ifelse(lispval* v, lispenv* e)
if( choice->type == LISPVAL_NUM && choice->num == 0){
lispval* answer = clone_lispval(alternative);
if(answer->type == LISPVAL_QEXPR){
answer->type = LISPVAL_SEXPR;
answer = evaluate_lispval(answer, e);
}
return answer;
}else {
lispval* answer = clone_lispval(result);
if(answer->type == LISPVAL_QEXPR){
// answer = builtin_eval(answer, e);
answer->type = LISPVAL_SEXPR;
answer = evaluate_lispval(answer, e);
}
return answer;
}
}