Re: Conditional operator in Shell Arithmetic section

[uzibalqa]

------- Original Message -------
On Sunday, March 19th, 2023 at 7:41 AM, Lawrence Velázquez <vq@larryv.me> wrote:


> On Sat, Mar 18, 2023, at 1:59 PM, uzibalqa wrote:
> 
> > Have been reading the manual about the arithmetic conditional operation
> > described by
> > 
> > expr ? expr : exp
> > 
> > This is quite difficult to understand exactly how to use it.
> 
> 
> I'm sure there are ample C examples out there.

This is how it is described in the Awk Manual

selector ? if-true-exp : if-false-exp

Which is much more informative.


> > For instance, consider setting the variable opst to 0 when the length
> > of delim in positive in a bash script. One would use
> > 
> > opst=$(( ${#delim} > 0 ? 0 : 1 ))
> 
> 
> Or:
> 
> if [[ -n $delim ]]; then
> opst=0
> else
> opst=1
> fi
> 
> or:
> 
> [[ -n $delim ]]
> opst=$?
> 
> or:
> 
> opst=$((${#delim} < 1))
> 
> or:
> 
> opst=$((! ${#delim}))
> 
> As Greg said, if you don't understand the operator, don't use it.
> You have other options.
> 
> > There needs to be at least one example of actual use in a typical
> > situation.
> 
> 
> No, there doesn't.

There is need if you actually want to help readers.  The awk maintainers 
certainly understood the need for an actual use case (getting the absolute 
value of x).
 
> > I also suggest to include it in section "3.2.5.2
> > Conditional Constructs".
> 
> 
> It's already in Section 6.5. It does not belong in 3.2.5.2.

If you look at the Awk Manual, some maintainers are surely convinced that in 
belrongs in "6.3.4 Conditional Expressions".
 
> > Specifying conditional operator "expr ? expr : exp" simply as Shell
> > Arithmetic makes it very difficult to find in the manual.
> 
> 
> The index could be a little more comprehensive, I guess.

Would appreciate ways that are more likely to locate it.  It is widely known 
under the term Ternary Conditional often indexed with  ?:
 
So I could not search with that.  It would be good to include.

> --
> vq