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Var
Syntax
Var X
Var(X)
Var(S:STRING)

where X is the identifier of a CoCoA variable.
Summary
function calls by reference, other complex referencing
Description
In the first and second form 'Var' is used as a formal parameter to a
user-defined function.  It is used to pass a variable---not its
value---to the user-defined function.  The following example should
make the difference clear.

Example

Define CallByRef(Var L )  -- "call by reference": The variable referred
  L := 'new value';       -- to by L is changed.
EndDefine;
M := 'old value';
CallByRef(M);
M;
new value
-------------------------------
Define CallByVal(L)  -- "call by value": The value of L is passed to
  L := 'new value';  -- the function.
  Return L;
EndDefine;
L := 'old value';
CallByVal(L);
new value
-------------------------------
L;
old value.
------------------------------- 

In the third form, Var(S), references the value of the variable or ring
whose identifier is S:

Example

Var("a string") := 6; 
Var("a string");
6
-------------------------------
P := Record[Name = 'test', Value = 1];
X := 'Name';
P.Var(X);
test
-------------------------------
Var('myring') ::= Q[a,b];
Var('myring');
Q[a,b]
-------------------------------
Using Var('myring') Do (a+b)^2 EndUsing;
a^2 + 2ab + b^2
-------------------------------
See also: