Page:AITR-474.djvu/49

 environments (we count two environments as identical if they involve the same variable bindings, regardless of the number of "frames" involved; that is, the environment is the same inside and outside a (LAMBDA ...)). Assume a simple target machine with argument registers called reg1, reg2, etc. Now we make use of our knowledge that functions, and convert CALL-FUNCTION of certain variables always denote certain a known function to a simple GOTO. (We have actually done things backwards here; in practice this knowledge is used before generating any code. We have fudged over this issue here, but will return to it later. Our purpose here is merely to demonstrate the treatment of function calls as GOTOs.)