## )ERASE name(s)

Erases named global variables, functions, operators and classes from the active workspace. The command is followed by the name, or names, of the objects to be erased. If an item cannot be erased, a message to that effect is displayed. Local variables are not erased - use ŚEX if you wish to do this.

                 )ERASE ‘CC NEMO
           NOT FOUND: NEMO

#### Indirect erase

If one or more of the names following the )ERASE command is enclosed in parentheses and is the name of a variable which is a simple character scalar, vector or matrix, then the contents of the variable are interpreted as the name or names of items to be erased.

                 )VARS
           A       B       C       DATA    MAT
                 )ERASE A C
                 )VARS
           B       DATA    MAT
                 NAMES„ŚBOX 'B DATA'
                 NAMES
           B
           DATA
                 )ERASE (NAMES)      (rows of NAMES interpreted as object to erase)
                 )VARS
           MAT     NAMES
                 )ERASE NAMES
                 )VARS
           MAT
                 DATA„'A_NAME'
                 )VARS
                 DATA    MAT
                 )ERASE (DATA)       (same error message as direct erase)
           NOT FOUND: A_NAME

#### Erasing individual class members

)ERASE can be used to erase a member (a method of property) from a class definition, using dot notation in the form ClassName.MemberName to specify which member should be deleted. The change will immediately be reflected in any existing instances of the class:

          PT„ŚNEW COLOR_POINT
          PT.ŚNL 2     © List properties of object PT
    COLOR
    X
    Y
    Z
          )ERASE COLOR_POINT.Z
          PT.ŚNL 2     © Object PT now has one less property
    COLOR
    X
    Y

#### Erasing whole classes

)ERASE can also be used to erase a class definition (and all the methods and properties defined in it). Any instances of the class will become instances of the erased class's parent, if there is one, or of the NULL class, if the erased class did not have a parent. Similarly, any classes which inherited from the erased class will be re-parented so that they now inherit from the erased class's parent.

In this example, class `POINT3D` inherits from `COLOR_POINT` which in turn inherits from `POINT`. `PT` is an instance of `COLOR_POINT`:

          )CLASSES
    COLOR_POINT    POINT   POINT3D
          ŚCLASS POINT3D
    {POINT3D} {COLOR_POINT} {POINT}
          PT„ŚNEW COLOR_POINT
          PT.ŚCLASSNAME
    COLOR_POINT

If we erase the class `COLOR_POINT`, its child class `POINT3D` is re-parented. The instance `PT` becomes an instance of the original parent:

          )ERASE COLOR_POINT
          ŚCLASS POINT3D
    {POINT3D} {POINT}
          PT.ŚCLASSNAME
    POINT

If we now erase the class `POINT`, `POINT3D` will now have no parent, and the instance `PT` becomes an instance of the NULL class:

          )ERASE POINT
          PT.ŚCLASSNAME
    NULL
          ŚCLASS POINT3D
    {POINT3D}

Topic: APLX Help : Help on APL language : System Commands : )ERASE Erase names

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