BRL.Hook: Functions Source  


This module provides a generic way to hook into various BlitzMax commands, and to add support for hooks into your own code.

The following hook ids are currently used by BlitzMax modules:

Hook idDescriptionData
FlipHookA Max2D Flip is about to occurNull
EmitEventHookAn event has been emitted by a call to EmitEventA TEvent object
To hook into any of these functions, use AddHook with the specified hook id and your hook function.

To provide hook support for your own code, use AllocHookId to generate a valid integer hook id somewhere in your program's startup code. Then, when the section of code you would like to be 'hookable' is about to execute, simply call RunHooks with the previously generated hook id and your own custom 'data' object.

Functions

AllocHookIdAllocate a hook id
AddHookAdd a hook function
RunHooksRun hook functions
RemoveHookRemove a hook function

Function reference

Function AllocHookId()
ReturnsAn integer hook id
DescriptionAllocate a hook id
Information The returned hook id can be used with AddHook, RunHooks and RemoveHook.

Function AddHook( id,func:Object( id,data:Object,context:Object ),context:Object=Null,priority=0 )
ReturnsA hook object that can be used with the RemoveHook command.
DescriptionAdd a hook function
Information Add a hook function to be executed when RunHooks is called with the specified hook id.
Example
'This function will be automagically called every Flip
Function MyHook:Object( id,data:Object,context:Object )
	Global count
	
	count:+1
	If count Mod 10=0 Print "Flips="+count
	
End Function

'Add our hook to the system
AddHook FlipHook,MyHook

'Some simple graphics
Graphics 640,480,0

While Not KeyHit( KEY_ESCAPE )

	Cls
	DrawText MouseX()+","+MouseY(),0,0
	Flip

Wend

Function RunHooks:Object( id,data:Object )
ReturnsThe data produced by the last hook function
DescriptionRun hook functions
Information RunHooks runs all hook functions that have been added for the specified hook id.

The first hook function is called with the provided data object. The object returned by this function is then passed as the data parameter to the next hook function and so on. Therefore, hook functions should generally return the data parameter when finished.

Function RemoveHook( id,func:Object( id,data:Object,context:Object ),context:Object=Null )
DescriptionRemove a hook function
Information Removes the hook function specified by id, func and context.