Unittest helper module?

[Chad J]

Nathan Reed wrote:
> Chad J wrote:
>> I also gave a short shot at writing this, and realized that it would 
>> need a D expression evaluator, which I don't feel like writing right now.
> 
> Couldn't you just use string mixins for this?
> 
> Thanks,
> Nathan Reed

Maybe, but I wasn't able to figure out how.  If I wasn't interested in 
the intermediate values, it'd be easy, but I am interested in the 
intermediate values.

This is the problem I run into:
consider
ut.test("foo( foo(a) & foo(b) ) == 0");
Now I'd like to know what foo(a) and foo(b) evaluate to, as well as what 
foo(a) & foo(b) evaluates to.  So I can just mix that substring in and 
evaluate it and grab the value.  Then I mixin and evaluate the entire 
contents of foo(foo(a)&foo(b)).  This is where the problem starts: 
foo(a) and foo(b) were just evaluated 2 times, when they should have 
only been evaluated once.  For pure functions this is fine, but 
functions with side effects could break the unittest if this is done.

Using mixins with no analysis causes this foo(...) to be called 10 
times, when it should only be called 3 times.