Where should the type information be 114
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Nick Maclaren Some further comments, that may be out of date as google is not showing recent...
On Fri, 18 Mar 2005 16:10:23 -0700, Steve Richfie1d
Well, I might be misremembering, and it might have been 1980 :-) Regrettably, those references aren't precise enough to be sure which concept they are referring to. The Multics one...
Maybe the problem is a sloppy language spec? I can see no really good reason not to tighten the range of possibilites. For example, PL-I and Cobol have picture data types which allow you to use character representation of numbers. so if you try to represent numbers as character strings there has to be a set of rules to determine behaviour. In the example below, the compiler warns you the you may not know what you are doing, in the third addition the conversion of the string blows up because it isn't valid for conversion to the type implied by the expression.
tt: proc options(main); dcl a fixed dec(10); dcl f float bin(53); a = 1 + '5'; put skip list(a); f = 1.0 + '5.0'; put skip list(f); f = 1.0 + '5.fluff'; end; *EXIT*
a = 1 + '5'; ........^ %PLIG-W-NOTARITH, Implicit conversion. A nonarithmetic expression, a constant '5', has been used in a context requiring an arithmetic value. at line number 4 in file SYS$SYSDEVICE:TOM.SCRATCHPR.PLI;4
f = 1.0 + '5.0'; ..........^ %PLIG-W-NOTARITH, Implicit conversion. A nonarithmetic expression, a constant '5.0', has been used in a context requiring an arithmetic value. at line number 6 in file SYS$SYSDEVICE:TOM.SCRATCHPR.PLI;4
f = 1.0 + '5.fluff'; ..........^ %PLIG-W-NOTARITH, Implicit conversion. A nonarithmetic expression, a constant '5.fluff', has been used in a context requiring an arithmetic value. at line number 8 in file SYS$SYSDEVICE:TOM.SCRATCHPR.PLI;4
John, YES, another GE-Honeybucket jock! Don't forget the Repeat Double instruction that allowed you to construct your own instructions that ran at the same speed as hardwired...
%PLIG-I-SUMMARY, Completed with 0 errors, 3 warnings, and 0 informational messages. %LINK-W-WRNERS, compilation warnings in module TT file SYS$SYSDEVICE:TOM.SCRATCHPR.OBJ;4
A machine architecture that has an indirect bit for effective address calculation for all instructions. +--------------- Heh! Yes, I loved the...
6 6.000000000000000E+00 %PLI-F-ERROR, PL-I ERROR condition. -PLI-F-CONVERSION, PL-I CONVERSION condition. -PLI-I-ONSOURCE, The conversion source is '5.fluff'. -PLI-I-ONCNVPOS, The erroneous character is at position 3. %TRACE-F-TRACEBACK, symbolic stack dump follows image module routine line rel PC abs PC DPLI$RTLSHR 0 000000000006ADA4 00000000000ACDA4 DPLI$RTLSHR 0 000000000005413C 000000000009613C DPLI$RTLSHR 0 0000000000054014 0000000000096014 DPLI$RTLSHR DPLIUTLMAINHANDLER DPLI$UTLMAINHANDLER 2211 0000000000000028 00000000000B1DF8 ----- above condition handler called with exception 001E8324: %PLI-F-CONVERSION, PL-I CONVERSION condition. -PLI-I-ONSOURCE, The conversion source is '5.fluff'. -PLI-I-ONCNVPOS, The erroneous character is at position 3. ----- end of exception message 0 FFFFFFFF800A1E5C FFFFFFFF800A1E5C DPLI$RTLSHR 0 000000000006A04C 00000000000AC04C DPLI$RTLSHR 0 0000000000052294 0000000000094294 PR TT TT 8 00000000000002E0 00000000000302E0 0 FFFFFFFF802553D4 FFFFFFFF802553D4
Overloading + with concatenation is silly, it could have been a typo