Re: [bitbake-devel] [PATCH] parse: Forbid ambiguous assignments to ${.}, ${+}, and ${:} variables

[Nikolai Merinov <n.merinov@inango-systems.com>]

Hi Peter,

> The above made me ponder on the existence of $, { and } in the regular
> expression for the variable name and what that can be (ab)used for. I
> realized that it allows you do define really odd variables such as:
> 
> ${} = "foobar"
> } = "foobar"
> $ = "foobar"
> 
> And while you cannot access them directly using, e.g., "${$}", you can
> access them using, e.g., "${@d.getVar('$')"...
> 
> This also allows defining variables that do not match the syntax at all,
> e.g.:
> 
> EQUAL = "="
> ${EQUAL} = "bar"
> 
> which will define the variable "=" and where "${@d.getVar('=')}" then
> returns "bar" as expected...
> 
> I am not sure this is a problem or working as intended, but it is a bit
> odd.

I did not aware of bitbake development history, but I believe that there
can be only one reason to do it: Makefile allow same kind of bizarre things. 

    $ cat Makefile 
    name = ==არ გააკეთო==
    $(name) = Hello World
    all: ; echo $(==არ გააკეთო==)
    $ make
    echo Hello World
    Hello World
    $

Regards,
Nikolai