Re: COBOL, Article on new mainframe use

According to Lawrence D'Oliveiro  <ldo@nz.invalid>:

It doesn't require learning concepts that are strange to accountants or
bookkeepers.

>
Level numbers? “USAGE IS COMPUTATIONAL”? “RESERVE «n» ALTERNATE AREAS”,
“ALTER «target» TO PROCEED TO «dest»”? All the fun of the “MOVE”
statement?

We all agree ALTER was a mistake, but a lot of this stuff is straightforward to read if a
programmer uses it reasonably. Level numbers are not exotic; it's easy enough to see that
subfields are part of fields which are part of a record.  MOVE by name was pretty slick,
something that made it into PL/I but not into C or C++.

Oh, and compound interest requires working with transcendental functions,
doesn’t it?

Uh, no, it's just repeated multiplication. COBOL makes it easy to say what the precision
of each number is with the decimal point location to get the rounding right. I suppose if
you want to compute the APR for a daily compounded rate that's more complicated but not
something I'd expect in typical COBOL code, more likely to be an input that's changed when
they change the interest rate they charge.

If you want bond prices or internal rates of return, you need to compute the zero of a
long polynomial which is tedious (I did it for a financial package in the 1980s) but still
not transcendental, and in any event, I doubt either were common in the kind of
bookkeeping stuff COBOL was typically used for.

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