Is there a way to replace a built-in function?

[dunbarx at aol.com]

Graham


I thought the ability of HC to allow this was a plus. The best example was the "round" function, which, with a ".5" in the decimal portion of an argument, alternately rounded the integer portion up or down depending on whether that integer was odd or even.


Most people, like me, intercepted that function, and always rounded a ".5" up, like I was taught.


Anyway, when you ask for a "trick", why not just create "myLn". After all, you are the author.


Craig 



-----Original Message-----
From: Graham Samuel <livfoss at mac.com>
To: How to use LiveCode <use-livecode at lists.runrev.com>
Sent: Mon, Jan 5, 2015 7:55 am
Subject: Is there a way to replace a built-in function?


On the face of it, it’s impossible to replace a built-in function in LC. For 
example, take the function ln(x) - that’s natural logarithm. I’d like to 
redefine ln(x), but I can’t because the compiler won’t let me use a reserved 
word in a function definition.

I wonder if anyone can suggest a trick to allow a redefinition like this. If 
not, then roll on Widgets.

Graham

PS In case you want to know why I want to redefine this function, it’s for the 
following reason.  Generally, mathematicians say that ln(0) is undefined, 
whereas the limit as x approaches zero is minus infinity. This is a bit subtle, 
and LiveCode takes no real notice of this, so that in LC, ln(0) yields “-inf”. 
Despite a contrary definition in the LC dictionary, this text is then regarded 
as a number, which can cause confusion, at least to me. So my new ln(x) would 
yield undefined for ln(0) and would use a symbol for minus infinity which LC 
would not then recognise as a number.
_______________________________________________
use-livecode mailing list
use-livecode at lists.runrev.com
Please visit this url to subscribe, unsubscribe and manage your subscription 
preferences:
http://lists.runrev.com/mailman/listinfo/use-livecode