Items tagged with type-checking



To check my arguments in a procedure I need something like

myproc := proc(M :: Matrix(square, rational)

                       , N :: Matrix(shape=triangular[lower, unit], datatype = rational
                       , O :: Matrix(shape = square, dimension = 5


end proc;

How does that work in Maple? What is the correct Syntax? I tried many different things that doesn't fit.

Consider the following two test procedures for creation of the same module:

createModule1 := proc(dim::posint)
        export det;
        det := (x::Matrix(1..dim,1..dim)) -> Determinant(x);
    end module
end proc:


createModule2 := proc(A::Matrix(square))
    local dim;
    dim := RowDimension(A);
        export det;
        det := (x::Matrix(1..dim,1..dim)) -> Determinant(x);
    end module
end proc:

as well as the following code lines calling these:

createModule1(       2 ):-det(IdentityMatrix(2));

The first line executes unproblematically, while for the second line an error results concerning the dimensionality check 1..dim,1..dim of the matrix. Why is dim available/initialized in the first version, while not in the second?

I have two problems with type declarations in procedures. They seem to be related, so I'll ask both questions at once.

1. One problem is that I make this sort of declaration.


where n could be an integer or a float, but not negative nor complex. I'm not sure what's wrong with the code below: the type-checking fails, but I don't understand why. I followed the template laid out by Preben here:

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