Am I right in thinking that in rule specifications we could get rid of  
the ~dep(s) parameter of rules and have all deps be specified/ 
discovered dynamically via the 'build' argument ? Otherwise stated is  
~dep(s) just an optimization ?

Out of curiosity any idea in the cost of suppressing these arguments  
(i.e. was that road actually followed at some point) ?

If the answer to the first question is yes. Then I think the  
documentation could be made clearer by stating that what is asked to  
be built by the 'build' argument is considered as dependencies.  
However if you know some deps statically you can specify them as  
dep(s) argument this will just implicitely add  them to the list given  
to the 'build' argument.

Best,

Daniel