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Cond

conditional expression
Syntax

Cond B_1 Then E_1 EndCond
Cond B_1 Then E_1 Elsif B_2 Then E_2 Elsif ... EndCond
Cond B_1 Then E_1 Elsif B_2 Then E_2 Elsif ... Else E_r EndCond
Cond(B_1,E_1,B_2,E_2,...,E_r)

where the B_i's are boolean expressions and the E_i's are expressions.


Description
If B_n is the first in the sequence of B_i's to evaluate to TRUE, then E_n is returned. If none of the B_i's evaluates to TRUE, then Null is returned. The construct, Elsif B Then E can be repeated any number of times. Note: be careful not to type Elseif by mistake (it has an extraneous e).

The difference between Cond and If is that Cond is an expression which may be assigned to a variable; each of the E_i's is an expression, not a general sequence of commands (as their analogues in If might be).

Example
Define Sign(A)
 Return Cond A>0 Then 1 Elsif A=0 Then 0 Else -1 EndCond;
EndDefine;
Sign(3);
1
-------------------------------
Define PrintSign(A)
  Return Cond(A>0,"positive",A=0,"zero","negative");
EndDefine;
PrintSign(3);
positive
-------------------------------


See Also