Reader's Letters - Jim Owen [Revelation On-Line Wiki]

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.

====== Reader's Letters - Jim Owen=====

^Published By^Date^Version^Knowledge Level^Keywords^
|Sprezzatura Ltd|01 NOV 1990|2.021+|EXPERT|INT(), SPACE, FUNCTION|

"I've discovered something that might be of interest to some AREV
programmers regarding the calling of homemade functions. I had a function
called SPC which padded blank spaces onto a variable. For example

          X = 65
          Y = SPC(X,5,"R")

would return Y = '   65'. (Unsure as to why this differs from Y = 65 "R#5"
- Ed).

However I discovered that this function also changed X!

I wanted my function to work like INT() which does not change the value of
the variable inside the parens, only the value to the left of the '='.

RTI told me that the C-esque use of local vs global variables doesn't apply
to RBASIC. One way to solve it was to make parameter 1 a literal string.
This was done by calling the function thus

          X = 65
          Y = SPC(X:" ",5,"R")

Concatenating a null to the variable changes it to a string and does NOT
change X. Another way around the problem was to immediately stuff some other
variable with X on entering the function then operating on, and returning,
this new variable.

Incidentally the INT() function is in assembler and avoids the problem
altogether".


(Volume 2, Issue 6, Page 3)