Change table rule conditions' syntax

[antisvin]

We should allow to specify conditions in a more natural form, i.e. right now conditions have to be given as key__op : value but I would prefer key op value:

if:
   - key == 5
   - key > 5
   - key <= 5
   #etc.

The generic format would be:
attr1.[...].attrN [op value]

If [op value] is ommitted, this is equivalent to specifying [== True]

Currently operators that are supported are:

• bool conversion
• comparison
• string operators (contains/icontains)

Key supports lookup for:

• attr
• dictionary

Also, I think we should emulate django templates' behavior an call attrs if they are callable. This means that we'll have support for simple function calls (with no arguments). Actually passing parameters can't be expressed in the C-exp bit specification, so it would require a substantial rewrite.

[miraculixx]

👍 This is great. Thanks.

Actually passing parameters can't be expressed in the C-exp bit specification, so it would require a substantial rewrite.

how about my earlier proposal, along the lines of C(funcname__fn=args)?

[antisvin]

But we need to have results on the right, so we can't have args there. To be more specific, let's look for a way to define math.sqrt(foo) > 2. I don't think this can be done elegantly.

I have an idea that can work, will open a separate issue - don't want to derail discussion for this one.

[antisvin]

Written proposal in #23