Re: [Axiom-developer] numberOfEmptySlots

[Gabriel Dos Reis]

Gabriel Dos Reis <address@hidden> writes:

| Consider the following function from src/interp/clam.boot:
| 
|     numberOfEmptySlots cache==
|       count:= (CAAR cache ='$failed => 1; 0)
|       for x in tails rest cache while NE(x,cache) repeat
|       if CAAR x='$failed then count:= count+1
|       count
| 
| 
| The SBCL type checker does not like it because:
| 
|   * it is able to infer that cache is a list,
|   * '=' (coming from NE, which mean not =) can be applied only
|     to numbers.
| 
| Consequently, we have conflicting assumptions for the same value.  So, we 
| have a bug.  Now, looking back at the code, the expression
| 
|      NE(x,cache)
| 
| cannot be right.  Was it indended to be
| 
|     x /= cache
| 
| instead?

Looking more into it, I suspect it was supposed to be

      NEQ(x,cache)

where NEW is the macro (from vmlisp.lisp)


   (defmacro neq (a b) `(not (eq ,a ,b)))

-- Gaby