User-defined variables: why not?

[Michael Save]

Hi,

In VCL, the fact that you can't create your own variables at runtime
can sometimes be a limitation when writing very complicated configs.
You have to use the variables Varnish already has defined for you;
that is, resp.*, etc. You can of course use HTTP headers as temporary
variables, but that seems like a hack to me.

My question is: why doesn't VCL let you do custom variables? If I'm
not mistaking, a .vcl file is just an easy-to-read and easy-to-code
version of a C script (.vcl is compiled as .c at runtime), and it's
not too hard to create variables in C. Are user-defined variables ever
going to appear in VCL, or is that out of the scope of the Varnish
Cache project (if so, why)?

Thanks,
Michael