[RFC PATCH 02/28] cli: Add LIL shell
Kostas Michalopoulos
badsector at runtimeterror.com
Tue Jul 6 18:09:50 CEST 2021
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".
Kostas
More information about the U-Boot
mailing list