"Dan Bishop" <[EMAIL PROTECTED]> writes:
Name a problem space that inherently requires arrays to be 1-based rather than 0-based.
"inherently" is too strong a word, since after all, we could do all our computing with Turing machines.
Some algorithms are specified in terms of 1-based arrays. And most Fortran programs are written in terms of 1-based arrays. So if you want to implement a 1-based specification in Python, or write Python code that interoperates with Fortran code, you either need 1-based arrays in Python or else you need messy conversions all over your Python code.
I write Python code that interoperates with Fortran code all the time (and write Fortran code that interoperates with Python code, too). Very, very rarely do I have to explicitly do any conversions. They only show up when a Fortran subroutine requires an index in its argument list.
In Fortran, I do Fortran. In Python, I do Python.
Yes, there is some effort required when translating some code or pseudo-code that uses 1-based indexing. Having done this a number of times, I haven't found it to be much of a burden.
The book "Numerical Recipes in C" contains a lot of numerical subroutines written in C, loosely based on Fortran counterparts from the original Numerical Recipes book. The C routines are full of messy conversions from 0-based to 1-based. Ugh.
I contend that if they had decided to just write the C versions as C instead of C-wishing-it-were-Fortran, they would have made a much better library. Still sucky, but that's another story.
Again, this (along with nested scopes and various other things) was all figured out by the Algol-60 designers almost 50 years ago. In Algol-60 you could just say "integer x(3..20)" and get a 3-based array (I may have the syntax slightly wrong by now). It was useful and took care of this problem.
There's nothing that stops you from writing a class that does this. I believe someone posted such a one to this thread.
I have yet to see a concrete proposal on how to make lists operate like this.
-- Robert Kern [EMAIL PROTECTED]
"In the fields of hell where the grass grows high Are the graves of dreams allowed to die." -- Richard Harter
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