render@uiucdcsb.UUCP (11/21/84)
>PS: How many other languages let you write: > > IF KICK-BACK GREATER THAN 10 AND LESS THAN 100 THEN ... > >without having to mention kick-back twice? They don't design them like they >used to. Probably just as well. For what it is worth, in Icon one can say: if 10 < kick_back < 100 then ... or even the more interesting if kick_back = (10 | 100) then ... (the last being IF KICK-BACK EQUALS 10 OR 100 THEN...) Who says Ralph Griswold never came up with a couple a good features in a language? Hal Render U. of Illinois uiucdcsb!render
ian@ic-cs.UUCP (Ian W. Moor) (12/02/84)
[It went thataway]
In Pascal you can write IF KICK-BACK GREATER THAN 10 AND LESS THAN 100 THEN
as
IF Kick_back IN [10..100] THEN
or how about
IF Kick_back IN [10,20,30,40,50] THEN
if you only want multiples of 10 ?
--
Ian W. Moor {mcvax,vax135}!ukc!west44!ic-cs!im
Dept of Computing
Imperial College "The squire on a hippopotamus is equal to
180 Queen's Gate the son of the other two squires"
London SW7 2BZsteven@mcvax.UUCP (Steven Pemberton) (12/09/84)
In article <223@ic-cs.UUCP> ian@ic-cs.UUCP (Ian W. Moor) writes: > In Pascal you can write IF KICK-BACK GREATER THAN 10 AND LESS THAN 100 THEN > as IF Kick_back IN [10..100] THEN > > or how about IF Kick_back IN [10,20,30,40,50] THEN > if you only want multiples of 10 ? In B (the new one, not the predecessor of C) you can also write IF x in {-1; 10; 20; 30.5; 100*pi; 2**81; 100**1000-1}: etc. As already pointed out earlier, B allows you to say IF 10<x<100: (but these two examples are not equivalent, you understand). Steven Pemberton, CWI, Amsterdam; steven@mcvax
ndiamond@watdaisy.UUCP (Norman Diamond) (12/09/84)
> In Pascal you can write IF KICK-BACK GREATER THAN 10 AND LESS THAN 100 THEN > > as > IF Kick_back IN [10..100] THEN > > or how about > IF Kick_back IN [10,20,30,40,50] THEN > if you only want multiples of 10 ? True, but it requires an order of magnitude more CPU time than two comparisons. -- Norman Diamond UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!watdaisy!ndiamond CSNET: ndiamond%watdaisy@waterloo.csnet ARPA: ndiamond%watdaisy%waterloo.csnet@csnet-relay.arpa "Opinions are those of the keyboard, and do not reflect on me or higher-ups."
ags@pucc-i (Dave Seaman) (12/11/84)
>> In Pascal you can write IF KICK-BACK GREATER THAN 10 AND LESS THAN 100 THEN >> >> as >> IF Kick_back IN [10..100] THEN >> >> or how about >> IF Kick_back IN [10,20,30,40,50] THEN >> if you only want multiples of 10 ? > >True, but it requires an order of magnitude more CPU time than two comparisons. An order of magnitude? Not if it's properly implemented. The indicated condition needs only ONE comparison, plus most likeley a rotation and perhaps an indexing operation. -- [This is my bugkiller line. It may appear to be misplaced, but it works.] Dave Seaman My hovercraft is no longer full of ..!pur-ee!pucc-i:ags eels (thanks to my confused cat).
mccaugh@uiucdcs.UUCP (12/30/84)
I believe the set-expression you want for: 10 < KICK-BACK < 100 should be
kickback in [11..99], not kick_back in [10..100].
Also, as the following extraction of VAX-code demonstrates, the set-expression
appears to be the less tedious of the two alternatives, to wit:
/* set-expression */ /* conditional-expression */
clrl r0 movl _kickback,r0
subl2 r2,r1 movl $10,r1
cmpl r1,r3 cmpl r0,r1
jgtru 1f jleq L9999
jbc r1,(r4),1f movl $1,r0
incl r0 jbr L9998
1: L9999:
tstl r0 clrl r0
jeql L7 L9998:
moval _output,-12(fp) movl _kickback,r1
(* is the code for the *) cvtbl $100,r2
(* following set-expr. *) cmpl r1,r2
if kickback in [11..99] then jgeq L9997
writeln(kickback); movl $1,r1
jbr L9996
L9997:
clrl r1
L9996:
mcoml r1,r1
bicl2 r1,r0
jeql L6
moval _output,-12(fp)
(* is the code for the *)
(* following cond-expr *)
if (kickback > 10) and
(kickback < 100) then
writeln(kickback);
--uiucmsl!mccaughndiamond@watdaisy.UUCP (Norman Diamond) (01/02/85)
> I believe the set-expression you want for: 10 < KICK-BACK < 100 should be > kickback in [11..99], not kick_back in [10..100]. [I agree -- N.D.] > Also, as the following extraction of VAX-code demonstrates, the set-expression > appears to be the less tedious of the two alternatives, to wit: > > /* set-expression */ /* conditional-expression */ > > clrl r0 movl _kickback,r0 > subl2 r2,r1 movl $10,r1 > cmpl r1,r3 cmpl r0,r1 > jgtru 1f jleq L9999 > jbc r1,(r4),1f movl $1,r0 > incl r0 jbr L9998 > 1: L9999: > tstl r0 clrl r0 > jeql L7 L9998: > moval _output,-12(fp) movl _kickback,r1 > (* is the code for the *) cvtbl $100,r2 > (* following set-expr. *) cmpl r1,r2 > if kickback in [11..99] then ... [this column of code] > writeln(kickback); ... [truncated by N.D.] The code shown for the set-expression doesn't seem to involve 11 and 99. What are the original contents of R1 and R2? I think that not all of the relevant generated code is shown. -- Norman Diamond UUCP: {decvax|utzoo|ihnp4|allegra|clyde}!watmath!watdaisy!ndiamond CSNET: ndiamond%watdaisy@waterloo.csnet ARPA: ndiamond%watdaisy%waterloo.csnet@csnet-relay.arpa "Opinions are those of the keyboard, and do not reflect on me or higher-ups."
chris@umcp-cs.UUCP (Chris Torek) (01/04/85)
> Also, as the following extraction of VAX-code demonstrates, the > set-expression appears to be the less tedious of the two alternatives, > to wit: (followed by lots of assembly) Actually, all this proves is that the Pascal compiler ``pc'' produces pretty lousy code. Since the expressions if x in [a..b] then and if (x >= a) and (x <= b) then are equivalent for x, a, b \elem Z (integers), the code produced should ideally be equivalent. -- (This line accidently left nonblank.) In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (301) 454-7690 UUCP: {seismo,allegra,brl-bmd}!umcp-cs!chris CSNet: chris@umcp-cs ARPA: chris@maryland