On 7/6/21 12:09 PM, Kostas Michalopoulos wrote:
On 7/6/2021 6:43 PM, Tom Rini wrote:
I don't know if it's right either. But drawing on my comment just now
and above about complex boot scripts, I also don't know if "it's sh but
quirky and incomplete, WHY DOESN'T THIS WORK RIGHT" is better than "It's
TCL? I don't know that, let me hit stackoverflow and do a little
reading" as would be the common experience. Especially if we document
up-front what the quirks we have are.
I think the same would happen with Tcl and LIL. LIL might look similar
to Tcl (and it is inspired by it), but it doesn't have the same
syntax. A big difference comes from how variables are parsed with LIL
allowing more variables symbols than Tcl without requiring escaping
which affects some uses like expr, so e.g. in Tcl this
set a 10 ; set b 20 ; expr $a+$b
will give back 30 however in LIL will give back 20. This is because
Tcl parses "$a+$b" as "$a" "+" "$b" whereas LIL parses it as "$a+"
"$b", evaluates "$a+" as an empty string (there isn't any "a+"
variable), "$b" as 20 and then just runs expr with the single argument
"20".
IMO both of these are nuts. I think the best thing to do here is
to raise an error about a missing variable "a+" to force the user to
rewrite this as
set a 10 ; set b 20 ; expr ${a}+$b
removing the ambiguity. Although I would generally like to follow TCL's
lead, there are several places where TCL does crazy things (e.g.
comments) which I have purposely not replicated.
--Sean
