Comments on: Variable Names

By: Richard

Richard — Mon, 11 Aug 2008 11:46:41 +0000

John Backus, “The History of Fortran I, II, and III,” IEEE Annals of the History of Computing, vol. 20, no. 4, pp. 68-78, Oct-Dec, 1998

and

Knuth Donald E. and PardoLuis Trabb, “Early Development of Programming Languages,” Encyclopedia of Computer Science and Technology, vol. 7, p. 419.New York: Marcel Dekker, 1977.

should cover your needs for Fortran references, the former is accessible on the web, the latter AFAIK only in paper format

By: martin

martin — Sat, 02 Aug 2008 10:17:24 +0000

I believe too that scope is the key. For scopes that are just a few lines it really don’t matter if you can grep for it.
And then there are problems where you step by step convert something to what you need.
e.g. you have a parameter fileName, and need to build a chain of new variables to use it in the function. sure i could name them fileNameFile, fileNameInputStream, fileNameReader, but that’s really useless clutter, in such chains it’s often much more useful to name the first variable readable and the last (if it’s scope is big enough) and give the one’s in the middle just “type code” variable names from the classes of the instances they refer to.

By: rchrd

rchrd — Wed, 30 Jul 2008 23:42:34 +0000

In any case, Fortran allows one to say that
“GOD is REAL, NIRVANA IS NOT”

By: rchrd

rchrd — Wed, 30 Jul 2008 23:40:56 +0000

The reason why i, j, k, l, m, n were chosen as integer variable names (or names beginning with those letters) in Fortran was because it is that way in written mathematics.

When you write a summation with a sigma sign, the summation variable is usually “i” or “k” and the upper limit is usually “n”. Go check any calculus textbook.

A polynomial’s coefficients are usually expressed as integer subscripts, so a sub i (I can’t write it that way in this comment) gets converted to A(I) in Fortran. This would be the i-th coefficient in a polynomial like

A1*X + A2*X**2 + …

And if a DO loop is analogous to a summation, then:

DO 1 I=1,N
Y = Y + A(I)*X**I
1 CONTINUE

is the way to write the evaluation of a polynomial. (Remember, Fortran arrays start at 1).

Fortran was designed to do numerical calculations … FORmula TRANslation.

By: Andres Salomon

Andres Salomon — Wed, 30 Jul 2008 21:13:16 +0000

If someone turns it into a 400-line block: shoot them. There’s a reason why programming languages support functions.

By: James Vega

James Vega — Wed, 30 Jul 2008 14:57:19 +0000

Paul: The difference between vim and vim-nox is that vim-nox includes the Perl, Python, Ruby, and TCL language bindings. The basic progression in the packaging is: vim-tiny (minimal), vim (base feature set which all packages aside from vim-tiny build on), vim-nox (vim + language bindings), vim-{gtk,gnome,lesstif} (vim-nox + gvim).

Russell: As indicated in my response to Paul, the vim package does indeed have syntax highlighting available. None of the packages turn on syntax highlighting by default, so there’s a discrepancy in user-side configuration somewhere (possibly “syntax on” is only in your ~/.gvimrc). Also, vim-{full,perl,ruby,python,tcl} are just transitional packages as of Lenny.

James (with my pkg-vim maintainer hat on)