Menu
▾
▴
[Tcl-bugs] [ tcl-Bugs-542588 ] bug in expr error handler
|
From: <no...@so...> - 2002-04-17 19:40:58
|
Bugs item #542588, was opened at 2002-04-11 11:05 You can respond by visiting: http://sourceforge.net/tracker/?func=detail&atid=110894&aid=542588&group_id=10894 Category: 44. Bytecode Compiler Group: 8.4a5 Status: Open Resolution: None Priority: 5 Submitted By: Nobody/Anonymous (nobody) Assigned to: miguel sofer (msofer) Summary: bug in expr error handler Initial Comment: % set begin 6658020034 6658020034 % set end 658020034 658020034 % expr abs($end - $begin) integer value too large to represent % expr { abs($end - $begin) } can't use floating-point value as operand of "-" % expr { abs(658020034 - 6658020034) } integer value too large to represent Can someone explain where Tcl thinks the floating point value is? And why is a floating point value not a valid operand of "-"? - Phil Ehrens This is just an example of too much sharing of a common routine for producing an error message. There's one routine for generating the "illegal operand" error message, and by the time it is called, the context isn't around any more to tailor the message precisely. So the error message generator knows that "658020034" was "bad", and it can see that that is a legal floating-point value, so it assumes that the error is that a floating-point value was used where it should not be. Go ahead and file a bug report under the "ByteCode Compiler" Category. - Don Porter ---------------------------------------------------------------------- >Comment By: Jeffrey Hobbs (hobbs) Date: 2002-04-17 12:40 Message: Logged In: YES user_id=72656 I don't think you are reading the docs right (or they aren't written clearly). 'expr foo' fails as well, but expr {"foo"} and expr {"08"} are both OK. ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-17 05:58 Message: Logged In: YES user_id=148712 According to expr.n: "If no numeric interpretation is possible, then an operand is left as a string (and only a limited set of operators may be applied to it)." As I understand that, the following is indeed a bug: % set a 08 08 % expr $a "08" is an invalid octal number % expr 08 "08" is an invalid octal number The source of misunderstanding is obviously in "no numeric representation is possible": tcl seems to say that "08" can be represented as a number, which happens to be invalid - I'd rather say that 08 cannot be represented as a number. In the same vein, how should we interpret a string of digits that is too large to represent as an integer: "an integer too large to represent", or "a string that cannot be represented as a number"? ---------------------------------------------------------------------- Comment By: Jeffrey Hobbs (hobbs) Date: 2002-04-16 16:03 Message: Logged In: YES user_id=72656 No, those are being treated as normal strings. That has always been a behavior of expr. ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-16 16:00 Message: Logged In: YES user_id=148712 Are these bugs too? % set a 08 08 % expr $a "08" is an invalid octal number % expr {$a} 08 % set b 665802003400000000000000 665802003400000000000000 % expr $b integer value too large to represent % expr {$b} 665802003400000000000000 ---------------------------------------------------------------------- Comment By: Andreas Kupries (andreas_kupries) Date: 2002-04-16 15:58 Message: Logged In: YES user_id=75003 Ok. I also prefer that the path should produce the same message. If that is not possible I am willing to settle for different yet correct messages. ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-16 15:55 Message: Logged In: YES user_id=148712 Yes, in my mind (and in the evolving patch), the problem to fix is "both paths should produce the same error messages, but don't". All of these fall in *that* category, although some are less severe as they produce different but correct messages. Maybe it is not necessary to produce the same error message,as long as it is a correct one? ---------------------------------------------------------------------- Comment By: Andreas Kupries (andreas_kupries) Date: 2002-04-16 15:47 Message: Logged In: YES user_id=75003 Why is that a sibling ? The leading 0 tells tcl to interpret 08 as an octal number, but 8 is not a valid octal digit, Hence it is an invalid octal number, and the message is essentially correct in both cases. Or is the problem that the message is different for the two cases ? ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-16 15:46 Message: Logged In: YES user_id=148712 More ... % set a 08 08 % expr abs($a) "08" is an invalid octal number % expr {abs($a)} argument to math function was an invalid octal number The error cases follow a different path, and produce different results.In this particular case, I like the second one better ... ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-16 15:41 Message: Logged In: YES user_id=148712 Another sibling is % set a 08 08 % expr $a+1 "08" is an invalid octal number % expr {$a+1} can't use invalid octal number as operand of "+" ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-16 08:45 Message: Logged In: YES user_id=148712 Related bug (the relationship is in the cause, not the symptom): % set begin 665802003400000000000000 665802003400000000000000 % expr {1 && $begin} 1 % expr 1 && $begin integer value too large to represent ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-15 11:40 Message: Logged In: YES user_id=148712 Note that 'abs' has nothing to do with it % set begin 665802003400000000000000 665802003400000000000000 % expr $begin - 1 integer value too large to represent % expr {$begin - 1} can't use floating-point value as operand of "-" ---------------------------------------------------------------------- Comment By: miguel sofer (msofer) Date: 2002-04-15 11:34 Message: Logged In: YES user_id=148712 Note that this particular example fails to produce the error in tcl8.5 (Donal's 64 bit arithmetic), but it can be reproduced by going beyong the 64-bit limit: set begin 665802003400000000000000 ---------------------------------------------------------------------- You can respond by visiting: http://sourceforge.net/tracker/?func=detail&atid=110894&aid=542588&group_id=10894 |