Makes a new procedure called
newname that is identical to procedure
oldname, which may be a primitive.
newname is already defined, its previous definition is lost.
newname is already a primitive, the redefinition is not permitted unless the variable REDEFP has the value TRUE.
Definitions created by COPYDEF are not saved by SAVE; primitives are never saved, and user-defined procedures created by COPYDEF are buried.
(You are likely to be confused if you PO or POT a procedure defined with COPYDEF because its title line will contain the old name.
This is why it's buried.)
TO WELCOME PRINT "Hello END WELCOMEHello
COPYDEF "SAYHELLO "WELCOME SAYHELLOHello