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by p_l 2432 days ago
None and none, as what you need is to alias the symbols for most lisps.
2 comments
wostusername 2432 days ago
Been a while since I've done Lisp seriously, but I don't believe that's possible, at least in Common Lisp (SBCL). While if responds to symbol function:

  * (symbol-function 'if)
  #<CLOSURE (:SPECIAL IF) {1000C5084B}>
SBCL refuses to set that value to an alias:

  * (setf (symbol-function 'foo) (symbol-function 'if))
  #<THREAD "main thread" RUNNING {10005205B3}>:
    #<CLOSURE (:SPECIAL IF) {1000C5084B}> is not acceptable to (SETF SYMBOL-FUNCTION)
Trying this with regular functions works as intended:

  * (setf (symbol-function 'bar) (symbol-function 'mapcar))
  #<FUNCTION MAPCAR>
  * (bar #'1+ '(1 2 3))
  (2 3 4)
Special forms are, well, special and a lot of the regular parts of lisp doesn't work with them.
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p_l 2430 days ago
hmm, I think worst case symbol-macro should work there :/

I expected specials to work in this case, but apparently not.

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kazinator 2432 days ago
Yes; alias the symbols that are macro operators or special operators via macros, and alias other kinds of symbols in their respective namespaces.

Variables may also have to be done with macros, because you want an assignment to a translated variable name to appear in the original variable. Some Lisp dialects perhaps allow a variable cell to have a binding to two or more symbols which could do the same thing.

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