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2 Francy Callbacks

Callbacks are objects holding a Function, a list of arguments and a trigger event. Callbacks are used to execute GAP code from a remote client using the Trigger Operation.

Callbacks can be added directly to Menus and Shapes.

Please see Francy-JS for client implementation.

2.1 Categories

In this section we show all Francy Callback Categories.

2.1-1 IsCallback

Returns: true or false

Identifies Callback objects.

2.1-2 IsRequiredArg

Returns: true or false

Identifies RequiredArg objects.

2.1-3 IsArgType

Returns: true or false

Identifies ArgType objects.

2.1-4 IsTriggerType

Returns: true or false

Identifies TriggerType objects.

2.2 Families

In this section we show all Francy Callback Families.

2.3 Representations

In this section we show all Francy Callback Representations.

2.3-1 IsCallbackRep

Returns: true or false

Checks whether an Object has a Callback internal representation.

2.3-2 IsRequiredArgRep

Returns: true or false

Checks whether an Object has a RequiredArg internal representation.

2.3-3 IsArgTypeRep

Returns: true or false

Checks whether an Object has a ArgType internal representation.

2.3-4 IsTriggerTypeRep

Returns: true or false

Checks whether an Object has a TriggerType internal representation.

2.4 Operations

In this section we show all Francy Callback Operations.

2.4-1 Callback

Returns: Callback

Creates a Callback object that holds a Function and the RequiredArgs to be executed by a TriggerType.

Please note, the Function must always Return

Examples:

Create a simple Callback with no arguments:

gap> MyFunction := function() return "Hello World!"; end;
gap> callback := Callback(MyFunction);
gap> Id(callback);

Create a Callback with one required argument of type string:

gap> MyFunction := function(str) return Concatenation("Hello", " ", str); end;
gap> callback := Callback(MyFunction);
gap> arg := RequiredArg(ArgType.STRING, "Your Name");
gap> Add(callback, arg);

Create a Callback with one known argument of type string:

gap> MyFunction := function(args) return args; end;
gap> callback := Callback(MyFunction, ["Hello World"]);

Create a Callback with one known argument and one required argument of type string:

gap> MyFunction := function(a,b) return Concatenation(a, b); end;
gap> callback := Callback(MyFunction, ["Hello "]);
gap> arg := RequiredArg(ArgType.STRING, "Your Name");
gap> Add(callback, arg);

Create a Callback with one known argument and one required argument of type string and double click trigger Type:

gap> MyFunction := function(a,b) return Concatenation(a, b); end;
gap> callback := Callback(TriggerType.DOUBLE_CLICK, MyFunction, ["Hello "]);
gap> arg := RequiredArg(ArgType.STRING, "Your Name");
gap> Add(callback, arg);

In order to see the output of the previous examples, we have to simulate the external call to Trigger operation:

gap> MyFunction := function(a,b) return Concatenation(a, b); end;
gap> callback := Callback(TriggerType.DOUBLE_CLICK, MyFunction, ["Hello "]);
gap> arg := RequiredArg(ArgType.STRING, "Your Name");
gap> SetTitle(arg, "Enter your name");
gap> Title(arg);
gap> Add(callback, arg);
gap> SetValue(arg, "Manuel"); # simulate the user input
gap> Value(arg);
gap> Trigger(GapToJsonString(Sanitize(callback))); # simulate the external trigger

Create a Noop Callback, useful for Menu holders, where no Function is required:

gap> callback := NoopCallback();

2.4-2 NoopCallback

Returns: Callback

Creates an empty Callback object that does nothing. Useful to create menu holders.

2.4-3 RequiredArg

Returns: RequiredArg

Creates a Callback with a RequiredArg. RequiredArg is user input driven and required for the execution of a Callback Function. The value for this argument will be provided by the user.

2.4-4 Trigger

Returns: the result of the execution of the Callback defined Function

Triggers a Callback Function in GAP. Gets a JSON String object representation of the callback to execute.

2.4-5 Add

Returns: Callback

Adds a RequiredArg to a specific Callback.

2.4-6 Remove

Returns: Callback

Removes a RequiredArg from a specific Callback.

2.5 Globals

In this section we show the Global Callback Francy Records for multi purpose.

2.6 Attributes

In this section we show the Francy Callback Attributes

2.6-1 Title

Returns: IsString with the title of the object

A title on a RequiredArg is used to retrieve input from a user.

2.6-2 Title

2.6-3 SetTitle

Sets the title of the RequiredArg.

2.6-4 Value

Returns: IsString with the value of the object

A value on a RequiredArg is the actual input value to be passed to back gap from the client GUI. These values are stored as String for convenience, even if the ArgType specified for the RequiredArg is of another type. Hence, explicit conversion is required within the Callback Function.

2.6-5 Value

2.6-6 SetValue

Sets the value of the RequiredArg.

2.6-7 ConfirmMessage

Returns: a IsString with the message to be shown to the user before the Callback execution.

This will display a confirmation message before any Callback is executed.

2.6-8 ConfirmMessage

2.6-9 SetConfirmMessage

Sets the value of the confirmation message to display to the user.

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