Complexes package doesn't work with plain matrices

[mahrud]

The documentation for complex claims:

This constructor minimizes computation and does very little error checking. To verify that a complex is well constructed, use isWellDefined(Complex).

However, when defining a complex it seems the source and targets are held to a higher standard than chainComplex:

i1 : needsPackage "Complexes";

i2 : R = QQ[x,y];

i3 : complex { matrix {{x, y}}, matrix {{-y}, {x}} }
stdio:3:7:(3): error: map with index 2 has inconsistent target

i4 : chainComplex { matrix {{x, y}}, matrix {{-y}, {x}} }

      1      2      1
o4 = R  <-- R  <-- R

     0      1      2

o4 : ChainComplex

Is there a reason why the targets are not adjusted on the fly similar to chainComplex?

i5 : target o4.dd_2 === source o4.dd_1

o5 = true

cc: @mikestillman @ggsmith

[mikestillman]

@ggsmith Perhaps we should allow this, as otherwise it might break alot of people's code?

[mahrud]

Not exactly the same issue, but related:

i1 : R = QQ[x];

i2 : C = complex R^1;

i3 : map(C, C, id_(R^1))
stdio:3:3:(3): error: no method found for applying ring to:
     argument   :  R (of class PolynomialRing)

Perhaps this should be an error, but not this error!

[ggsmith]

I agree: the error message should be improved.

[mahrud]

Why not fix the targets on the fly, perhaps issuing a warning so the user is aware?