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On 18/04/15 21:28, PMA wrote: > J Martin Rushton wrote: > > <snip> > > FORTRAN also insists on the distinction (at least officially). In > FORTRAN you CALL procedures as a single statement whereas you > simply use functions in an expression. If you try to mix them the > compiler _ought_ to throw the syntax out. Likewise BASIC > distinguishes between GOSUB and invoking a function in an > expression. > > Consider writing a procedure to perform a task. If this is invoked > as a function then what is the return value? It might be anything > that was left in the register used to pass the value back; worse, > if returning by reference then you could be interpreting random > data as an address! Modern compilers often trap this by zeroing > the return value, but you can't rely on it. > > You also need to keep in mind that the syntax checking of 2& 3 > GLs was not as extensive as modern languages like C/C++. Pascal, > in particular, was designed as a single pass language so that cards > or tape could be read in, passed sequentially through the compiler > and the object code stored to tape. In the 1970s even mainframes > often only had 128 KiB of memory. Saving a few machine > instructions may seem trivial today, but major programs were often > only kibibytes in length in the 1960s. >> >> _______________________________________________ lilypond-user >> mailing list lilypond-user@gnu.org >> https://lists.gnu.org/mailman/listinfo/lilypond-user > Martin, > > Thank you for this! (And obviously after 40+ years, I have > forgotten my BASIC.) > > PMA Getting a bit OT, but I've just had a quick look in my books. Ada and PL/1 also make the distinction, the former is possibly slightly surprising given its object-orientated pretensions. COBOL is fascinating though, it has procedures, subprograms but no functions. Procedures are unparametised blocks of code within the same compilation unit accessed by a PERFORM statement. To use a subprogram you needed to write it as a separate compilation unit and invoke it with CALL <subproc> USING <param> [...] All in all it was a lot easier in machine code. ;-) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJVMsPcAAoJEAF3yXsqtyBlUZwP/3w5Twm7fvKfZFGFXH5iZ/pV vBI4R37WpUgCZI2QnYuWvyZtRQEJOmIJzfdifwETsQYUZtG0QHgchF6er4H61DUz 9vkVlv7+rHAh8W5ggQubchHnpVERybV54Jrm3Zee1JAPicjlkmgWznp2f4jA+kOw PSViycVAJ5Pscjkb6O4ggpANtf2D/hZQATEN6J1RqGYnrLbP1NkWz7dCHkcxJVhx 5Thr1i3i3ZKIGlTVT4vhFGtcokKqSoSZxmRWly2xQMrvUMuRu7A8eaQohx5DALQn c3TKxfBMyOZu4M/5R0xQa3R7pepAqGvo+DhkilnRC4JfLxqL8N8emY4shDyobQn4 ml7zckkiEgth6aIQBc4iWo+71q8uFw7OkNxaGRjbE/19V3jfb+MrcfaA8BqrQ//Q 37kaXineP9vO1iZevYe/cMwO21UIJPUAfVr3UypXPXSQ63Af4JBVil9UeAZ7H9Sf XnjJs0vHgBrz/Xbk9Xd/2mgp6lYoO2Gn7xIEdoOczDObRcJgoTsngV7O3vp9OGwB i/yHAi75Oy1fYpVz1ig9JwrgBBcL/AiZVP2EhdaitGHBP+yfIns9uZuONIUPNlpc xAL9CN4SoSHldGDmw0bflDxPq0T8SjbtsRfT19ONw5OtP0L+73u4huaAAJK1Dwd8 e/ORmlkZ8a9xmHU7alag =1V4Q -----END PGP SIGNATURE----- _______________________________________________ lilypond-user mailing list lilypond-user@gnu.org https://lists.gnu.org/mailman/listinfo/lilypond-user
