Declined IF ISNUMBER ... ?

[vefatica]

Is there a simple way to determine if a string will represent a number when passed to @EVAL? If there is, I missed it. If not, it would be useful

 

[rconn]

@NUMERIC doesn't work for you?

 

[vefatica]

@NUMERIC doesn't work for you?

Not perfectly.

v:\> echo %@numeric[0xFF]
0

 

[Charles Dye]

There's @ISFLOAT. But if a string is not a number, @EVAL may interpret it as the name of an environment variable. Which may or may not be defined, which might or might not be a valid number. And then there are other strings like AND and SHR, which are not numbers, and PI, which is.... This is not a trivial question!

 

[vefatica]

There's @ISFLOAT. But if a string is not a number, @EVAL may interpret it as the name of an environment variable. Which may or may not be defined, which might or might not be a valid number. And then there are other strings like AND and SHR, which are not numbers, and PI, which is.... This is not a trivial question!

And the likes of log(2) also. I had in mind things that are literally numbers (to @EVAL) ... like the various built-in functions.

And I was really thinking of a unary conditional expression as opposed to a variable function.

 

[rconn]

Not perfectly.

v:\> echo %@numeric[0xFF]
0

So you want a function that supports binary, octal, hex, decimal, and float?

 

[vefatica]

So you want a function that supports binary, octal, hex, decimal, and float?

I was thinking of anything that @EVAL would take. I don't think octal is in there (is it?) but there is also scientific notation. It's not particularly important to me.

 

[rconn]

I was thinking of anything that @EVAL would take. I don't think octal is in there (is it?) but there is also scientific notation. It's not particularly important to me.

Yes, @EVAL takes all of those.

 

[Charles Dye]

Yes, @EVAL takes all of those.

Really? How do you specify octal in @EVAL?

Not that I care. Octal is for paleolithic computers....

 

[AnrDaemon]

Does not look like so.

@ECHO %@EVAL[017 + 012]

=29, should be 25.

 

[Charles G]

Does not look like so.

@ECHO %@EVAL[017 + 012]

=29, should be 25.

How does EVAL know it's octal and not not = to 29 ?

 

[Alpengreis]

Because the leading 0 ... see here:

https://en.wikipedia.org/wiki/Octal#In_computers

Unfortunately that doesen't work for @EVAL ... and also the others there don't work.

 

[Alpengreis]

At the moment it SEEMS there is no "direct" way to use octal with @EVAL.

A workaround with:

echo %@eval[%@convert[8,10,17]+%@convert[8,10,12]]
25

works (of course).

 

[rconn]

Is there a simple way to determine if a string will represent a number when passed to @EVAL? If there is, I missed it. If not, it would be useful

Well, you could pass it to @EVAL and then check the return code to see if @EVAL thought there was an error.

 

[rconn]

Does not look like so.

@ECHO %@EVAL[017 + 012]

=29, should be 25.

@ECHO %@EVAL[0o17 + 0o12]
=25

 

[Alpengreis]

Ahh, oooook, thank you, Rex!