Design #829: PPOrderingCtor: name of mem fn which actually constructs? - CoCoALib - CoCoA Project

Design #829

PPOrderingCtor: name of mem fn which actually constructs?

Added by John Abbott over 8 years ago. Updated over 6 years ago.

Status:

Closed

Priority:

High

Assignee:

John Abbott

Category:

Tidying

Target version:

CoCoALib-0.99560

Start date:

30 Nov 2015

Due date:

% Done:

100%

Estimated time:

2.34 h

Spent time:

2.45 h

Description

Currently PPOrderingCtor has a mem fn called myCtor which accepts an integer arg and returns the ordering for than number of indets.

Might it be better to use operator() instead of myCtor?

Currently we do this

PPOrderingCtor ord = lex;
...
PPOrdering O = ord.myCtor(NumIndets);

Using operator() would let us write this more compact version:

PPOrderingCtor ord = lex;
...
PPOrdering O = ord(NumIndets);

It is more compact, but is it clearer? Or less clear? Does it matter?

History

#1 Updated by John Abbott over 8 years ago

We could also have both, but I do not usually like to offer two ways of achieving the same thing... a user might be puzzled as to why both exist (unless the documentation simply says they are equivalent and the user can choose whichever syntax pleases more).

In fact, I doubt any normal user would want to operate directly on objects of type PPOrderingCtor; it was just a "trick" to allow the user to write lex, StdDegRevLex etc as an ordering when creating a poly ring (or a PPMonoid).

#2 Updated by Anna Maria Bigatti over 8 years ago

Would it be possible to write PPOrdering O = lex(NumIndets);?
If not, I fear it might be more confusing.
In fact I would not call the variable ord,but ordctor,then the function should be ordctor. myMakeOrd(n) ....
... Ugly, I know...

#3 Updated by John Abbott over 8 years ago

Yes, it should be possible to write lex(NumIndets), but normally it would be enough to write just lex and let the called fn actually invoke the pseudo-ctor with the correct number of indets.

PPMonoidEv(symbols("x,y,z"), lex)
is equivalent to
PPMonoidEv(symbols("x,y,z"), lex(3))
just in the first version you do not need to worry about getting the number of indets right (since the call to PPMonoidEv does that automatically).