OKB (not okblacke) wrote: [snip] > I think the same could be said of virtually all exceptions. What I > think would be ideal is that whenever an exception is raised, the > traceback tells you: > > 1) What the exception is > 2) The names of the variables involved in the offending expression > (or their character position in the line) > 3) The values of those variables > > This would be especially useful in cases where you have some long > expression and you get a "cannot concatenate str and list" or whatever. > The irritating thing about this as it is is that you cannot tell which > variables in the expression are causing the problem. > > I realize that in some cases the offending expression may not be a > single variable, > but I am curious whether it would be possible for > something like this: > > "1" + "2" + "3" + "4" + 5 + "6"
A few points: 1. You have difficulty determining the "offending expression" in that example? 2. If I read your requirement properly, you want an error message that includes the following information from the source: example 1: "1" + "2" + "3" + "4" + 5 + "6" left operand name: "1" + "2" + "3" + "4" left operand value: "1234" right operand name: 5 right operand value: 5 example 2 (simple variables): str1 = "a"; list1 = ["b"]; foo = str1 + list1 left operand name: str1 left operand value: "a" right operand name: list1 right operand value: ["b"] example 3 (simple variables): str1 = "a"; str2 = "x"; list1 = ["b"]; foo = str1 + str2 + list1 left operand name: str1 + str2 left operand value: "ax" right operand name: list1 right operand value: ["b"] IMHO there would be no point in handling only "simple" cases like example 2 -- firstly, you don't need it; there's only one possible answer for "left operand name". Secondly, AFAICT, the same mechanism would handle examples of arbitrary complexity. My guesses: (a) Implementing this error reporting information in a new compiler and interpreter would add considerably to the effort required, and to the complexity and thus to the risk of error. (b) Retrofitting it to an existing compiler and interpreter would be a nightmare. Possible: yes. Cost/benefit ratio: very high. 3. The OP asked only for values; you are asking for names and values. If you have a magic flak jacket, please let me know; I'd like to borrow it occasionally :-) Cheers, John -- http://mail.python.org/mailman/listinfo/python-list
