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Version: 7.0

INPUT operator

The INPUT operator creates an action that inputs a primitive value or selects an object of a custom class.

Syntax​

INPUT inputOptions [LIST listExpr]
[CHANGE [= changeExpr]]
[DO actionOperator [ELSE elseActionOperator]]

inputOptions - input options. Specified by one of the following syntaxes:

[alias =] className
[alias] = expr

Description​

The INPUT operator creates an action which allows to request the value of one of the built-in classes from the user.

If className is a custom class, the operator requests an object of that class. Without an explicit LIST, interactive input opens the class selection form, while a programmatically supplied value is interpreted as the object's id. An explicit LIST offers the values of listExpr for selection (for example LIST name(o)); the value class of listExpr determines the inline editor.

Parameters​

  • className

    The name of a built-in class or a custom class. For a custom class, the input requests an object of that class.

  • listExpr

    An expression whose values are offered for selection. Used for a custom-class input to list candidate objects (the value class of listExpr determines the inline editor).

  • expr

    An expression, which value determines the initial value of the input.

  • alias

    The name of the local parameter to which the input result is written. Simple ID.

  • CHANGE

    A keyword specifying that in addition to the value input the result needs to be written to the specified property.

  • changeExpr

    An expression that determines the property to which the input result is written. By default, the property specified as the initial input value is used.

  • actionOperator

    A context-dependent action operator that is executed if the input was completed successfully.

  • elseActionOperator

    A context-dependent action operator that is executed if the input was cancelled. The input result parameter cannot be used as parameters.

Examples​

changeCustomer (Order o)  {
    INPUT s = STRING[100] DO {
        customer(o) <- s;
        IF s THEN
            MESSAGE 'Customer changed to ' + s;
        ELSE
            MESSAGE 'Customer dropped';
    }
}

FORM order
    OBJECTS o = Order
    PROPERTIES(o) customer ON CHANGE changeCustomer(o)
;

testFile  {
    INPUT f = FILE DO { // requesting a dialog to select a file
        open(f); // opening the selected file
    }
}