Advanced Search

Question: What is the usage of seq(depends(type))?

Question:What is the usage of seq(depends(type))?

sursumCorda 1079 Maple
procedure parameter argument depends
September 10 2024
1

According to the documentation, 

the depends modifier can be used in declaration to indicate that a parameter's type depends on the value of another parameter, the seq modifier declares that multiple arguments of a specific type within a procedure invocation will be assigned to a single parameter, and if the depends modifier is used together with the seq modifier, the declaration must be written: seq(depends(type)). 

So the code below works as expected: 

f0 := proc(x::Not(2), y::2) [[x], [y]] end:
f0(1, 2);
                           [[1], [2]]

f0(2, 2);
Error, invalid input: f0 expects its 1st argument, x, to be of type Not(2), but received 2

The code below also works as expected: 

f1 := proc(x::depends(Not(y)), y::2) [[x], [y]] end:
f1(1, 2);
                           [[1], [2]]

f1(2, 2);
Error, invalid input: f1 expects its 1st argument, x, to be of type Not(2), but received 2

The code below works as desired as well: 

f2 := proc(x::seq(Not(2)), y::2) [[x], [y]] end:
f2(0, 1, 2);
                         [[0, 1], [2]]

f2(2, 1, 2);
                           [[], [2]]

However, the following code does not work: 

f3 := proc(x::seq(depends(Not(y))), y::2) [[x], [y]] end:
f3(0, 1, 2);
Error, invalid input: NULL uses a 2nd argument, y (of type 2), which is missing
f3(2, 1, 2);
Error, invalid input: NULL uses a 2nd argument, y (of type 2), which is missing

I believe that the output of f3(0, 1, 2) and f3(2, 1, 2) should be the same as that of f2(0, 1, 2) and f2(2, 1, 2), respectively. Did I miss something? 
Please Wait...