set! is from Scheme. Lisp has had set and setq since the beginning along with prog (I don't know when progn was added). The LISP I manual describes the program

set! is from Scheme. Lisp has had set and setq since the beginning along with prog (I don't know when progn was added). The LISP I manual describes the program feature as being "like a FORTRAN program with LISP statements", but that's not the same as saying it is there to appeal to Fortran programmers. https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/mit/rle_lisp/LISP_I_Programmers_Manual_Mar60.pdf https://www.mirrorservice.org/sites/www.bitsavers.org/pdf/mi...