[Laszlo-dev] how many args is a dependency function supposed to have?

[P T Withington]

[cc-ing laszlo-dev for archiving]

The dependencies method for a method is called will all the arguments  
that the method is called with, plus, prepended to those args are the  
object the constraint is on (the first argument) and the object the  
dependency method is called on.  The safest thing for a dependency  
method that does not need any of these would just be to say  
`(...ignore)`.

I suspect all the dependency methods are wrong because arg count was  
never checked in the past.

Don't be fooled, like I always am by the two kinds of dependencies  
methods:

1) The ones like your example, which compute the dependencies of a  
method that might be used in a constraint

2) The dependency method for a constraint (which takes no arguments),  
which is automatically generated by the compiler and which is called  
to find the events to register on for updating the constraint.

The class 1 dependency methods are always written by hand, and they  
are used to make a method work in a constraint.  The compiler only  
automatically analyzes the constraint expression.  It does not delve  
into functions or methods that are called in the constraint  
expression, unless they have hand-written dependency methods.

On 2008-04-02, at 18:50 EDT, Henry Minsky wrote:
> I get this error:
>
> [trace] dummy LzBrowser getInitArg declared in core/dummyclasses.js
> [Fault] exception, information=ArgumentError: Error #1063: Argument
> count mismatch on LzView/$lzc$getMouse_dependencies(). Expected 0, got
> 3.
> Fault, <anonymous>() at $lzc$class_dragstate.as:26
> 26    return [this, "drag_axis", this, "__dragstate_xdoffset", this,
> "x"].concat(this["$lzc$__dragstate_getnewpos_dependencies"] ?
> this["$lzc$__dragstate_getnewpos_dependencies"](this, this, "x",
> this.immediateparent.getMouse("x") + this.__dragstate_xdoffset) :
> []).concat(this.immediateparent["$lzc$getMouse_dependencies"] ?
> this.immediateparent["$lzc$getMouse_dependencies"](this,
> this.immediateparent, "x") : [])
> (fdb) q
>
> The LzView method and dependency method are
>
>  */
> function getMouse( xory ) {
>    if (this.__movecounter != LzGlobalMouse.__movecounter) {
>        this.__movecounter = LzGlobalMouse.__movecounter;
>        this.__mousecache = this.sprite.getMouse(xory);
>    }
>    if (xory == null) return this.__mousecache;
>    return this.__mousecache[xory];
> }
>
> /** @access private */
> function $lzc$getMouse_dependencies( ) {
>    return [ LzIdle, "idle" ];
> }
>
> So what args should a dependency function expect to get called with,
> and are there always the same number?
>
>
> -- 
> Henry Minsky
> Software Architect
> hminsky at laszlosystems.com