previous  next
Shape
Syntax
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.
Summary
extended list of types involved in an expression
Description
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.

Example

Use R ::= Q[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
-------------------------------

There are undocumented functions, 'IsSubShape' and 'IsSubShapeOfSome',
for determining if the 'shape' of an CoCoA expression is a 'subshape'
of another.  To see the code for these functions, enter 
'Describe Function('$cocoa/misc.IsSubShape')' or 
'Describe Function('$cocoa/misc.IsSubShapeOfSome')'.
See also: