[Toybox] Would someone please explain what bash is doing here?

[Rob Landley]

On 5/24/20 4:32 PM, Chet Ramey wrote:
>> In new tab:
>>   $ echo $LINENO\
>>   > $LINENO
>>   22
>>   $ echo $LINENO
>>   3
>>
>> It cares about the space.
> 
> Of course it does!

It's not an "of course" for me. My code doesn't work like that.

> The space terminates the token!

Unquoted tokens self-terminate: ; or & or ( don't need a space before or after
them to be their own word. Therefore $LINENO can already _not_ be a function
definition before you get to the \ because it started with something _other_
than an unquoted "(".

> You can't return the
> first $LINENO until you process the backslash-newline and find a
> metacharacter that ends the word, which is the newline after the second
> $LINENO.
It's already categorized the word by that point and knows it's not a control
character. The trailing \ makes it return "need next line due to unfinished
quote" but the calling code doesn't behave differently because of it.

Rob