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5.1.10 ComputationStack
If the ComputationStack option is on, a special variable named ComputationStack contains a list tracing errors that occur during the execution of CoCoA commands. This option is useful for debugging programs.

Example 
  Define Test(X)
    If X>=0 Then PrintLn 1/X; EndIf;
  EndDefine;

  Set ComputationStack;
  Test(0);

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ERROR: Division by zero
CONTEXT: 1 / X
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  S := ComputationStack;  -- to save typing later
  S[1];  -- the command that produced the error
PrintLn(1 / X)
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  S[2];  -- S[1] was part of an If-statement
If X >= 0 Then PrintLn(1 / X) EndIf
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  S[3];  -- the command issued by the user
If X >= 0 Then PrintLn(1 / X) EndIf;
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