Entering formulas in scheduled transactions

[Jordan Kyriakidis]

Hello,

   I can't get the mortgage druid to work properly.  I think the
problem is that my mortgage is paid monthly but is compounded
semi-annually (not monthly).  I think that the druid assumes your
mortgage is compounded monthly.  (Is this correct?)  So I guess I have
two questions:

(1) Can I get the druid to compound semi-annually?  I can do this on
the included financial calculator but not on the druid.  By poking
around the various directory files, I gather that the important file
is fin.scm.  These formulas seem to implicitly assume that the payment
frequency (eg, monthly) is the same as the compounding frequency.  Is
this correct?

(2) How can I enter formulas directly?  I know all the compound
interest formulas, the present principal, interest amounts, and so on,
so I could simply enter them into the "credit" and "debit" formulas in
the scheduled transactions editor.  By playing around with the cells,
I gather that I can put an "i" to stand for the number of times the
scheduled transaction has executed.  I can also do simple addition
(+), multiplication (*), division (/), and so on.  But how do I do
exponentiation?  Doing 2^i doesn't work (I can't type "^"), nor does
2**i (I get errors about parsing the formula).  Is there a way to
enter exponentiation?

(3) Okay, I have a third question.  The mortgage druid seems to enter
formulas from the file fin.scm, with the parameters separated by
colons.  Can I write my own scheme function (eg, by copying and
hacking the fin.scm file) and call it from the "credit formula" cell
in the schedule transaction editor?  I tried this but it didn't work;
for one thing, it didn't recognize my function; for another, I
couldn't get the ":" to be typed into the window.  (I got "," to type,
but gave a parse error.)

I *really* want to use gnucash, but this loan thing is a bit of a
drag.  Thanks for any help.

Jordan

PS.  I think I've found a not-too-bad (ie, simple but inelegant)
workaround for doing budgeting within gnucash.  Maybe I'll explain it
here in another posting.