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extended list of types involved in an expression
Shape(E:LIST):LIST (of TYPE)
Shape(E:MAT):MAT (of TYPE)
Shape(E:RECORD):RECORD (of TYPE)
Shape(E:OTHER):TYPE
where OTHER stands for a type which is not LIST, MAT, or RECORD.
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This function returns the extended list of types involved in the
expression E as outlined below:
Type(E) = LIST
In this case, Shape(E) is the list whose i-th component is the type
of the i-th component of E.
Type(E) = MAT
In this case, Shape(E) is a matrix with (i,j)-th entry equal to the
type of the (i,j)-th entry of E.
Type(E) = RECORD
In this case, Shape(E) is a record whose fields are the types of the
fields of E.
Otherwise,
Shape(E) is the type of E.
Use R ::= QQ[x];
L := [1,[1,"a"],x^2-x];
Shape(L);
[INT, [INT, STRING], POLY]
-------------------------------
R := Record[Name = "test", Contents = L];
Shape(R);
Record[Contents = [INT, [INT, STRING], POLY], Name = STRING]
-------------------------------
It.Name;
STRING
-------------------------------
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There are undocumented functions,
IsSubShape and
IsSubShapeOfSome,
for determining if the
shape of a CoCoA expression is a
subshape
of another. To see the code for these functions, enter
Describe Function("$misc.IsSubShape");
Describe Function("$misc.IsSubShapeOfSome");