[squeakland] What is a parameter in etoys?

[Ricardo Moran]

Hi,

I modified the "User interface" chapter of the FLOSS manual to add Bert's
explanation about parameters. I replaced the first paragraph of the old text
with Bert's version. I just wanted to check with you to see if you approve
this change. FYI, the old version was:

-----------------------
*add parameter*

This option adds a parameter to the script. The parameter is passed into the
script when it is called from another script. For example if you can create
a script that will move an object forward based upon the number, you can add
a parameter of type number. Then call that script from one or more other
scripts passing in a specific value as the number. To use the parameter in
the script simply drag the parameter from the Script Editor's in the top
line to the right of the scripts name into your script where any number data
type can be used.

The following are the data types that can be used as parameters:


   - Boolean (true or false)
   - BorderStyle
   - ButtonPhase
   - Color
   - Graphic
   - ImageResolution
   - Number
   - Patch
   - Point
   - ScriptName
   - Sound
   - String
   - TrailStyle

-----------------------

On Tue, Mar 29, 2011 at 4:12 PM, Ricardo Moran <richi.moran at gmail.com>wrote:

> Ok, I'll do it tonight :)
>
>
> On Mon, Mar 28, 2011 at 1:51 PM, Bert Freudenberg <bert at freudenbergs.de>wrote:
>
>>
>> On 28.03.2011, at 15:58, Ricardo Moran wrote:
>>
>> Great explanation! I didn't know the difference between "arguments" and
>> "parameters" :)
>>
>>
>>
>> http://en.wikipedia.org/wiki/Parameter_(computer_programming)#Parameters_and_arguments
>>
>> BTW, is this written somewhere? It would be cool to add it to the
>> manual...
>>
>>
>> Go ahead and add it :)
>>
>> - Bert -
>>
>>
>> On Mon, Mar 28, 2011 at 10:02 AM, Bert Freudenberg <bert at freudenbergs.de>wrote:
>>
>>> On 28.03.2011, at 14:17, Christine Murakami wrote:
>>>
>>> Do you have some documentation on how parameters work in Etoys and what
>>> they can accomplish? I looked it up in your Floss manual but it was unclear
>>> to me where to find that information.
>>>
>>>
>>> Many tiles in Etoys have a parameter. It is a value that influences the
>>> behavior of that tile.
>>>
>>> For example, the "forward by" tile has a parameter that specifies how far
>>> the object should move. The "make sound" parameter specifies which sound to
>>> make. Etc.
>>>
>>> You can also make your own tiles. When you create a new script, a tile
>>> for it is placed in an object's "scripts" viewer category. That tile can be
>>> used in another script.
>>>
>>> The "add parameter" menu entry lets you add a parameter to your own tile.
>>> If you use that new tile in another script, you can set a specific value for
>>> the parameter just like with any other tile.
>>>
>>> Inside the script for your tile, that parameter is shown in the title
>>> bar. It is called "number" (unless you change the parameter type). You drag
>>> this "number" tile and use it like any variable tile in that script.
>>>
>>> E.g. in this script, I used the "number" tile four times:
>>>
>>> <PastedGraphic-1.png>
>>>
>>> Every time you use your new tile, you can give it another "concrete"
>>> value. That's why in the script itself, you only have the "abstract" value
>>> called "number". (Computer scientists call the concrete values "arguments"
>>> and the abstract values "parameters", but even programmers get confused
>>> about the distinction)
>>>
>>> <PastedGraphic-3.png>
>>>
>>> Note that after adding a parameter, you can not set your script to
>>> "ticking" anymore, because it now needs a parameter. It only gets a concrete
>>> value for the parameter from another script where your tile is used.
>>> Additionally, you can set a value in the viewer, and hit the yellow button
>>> to run your script with that value:
>>>
>>> <PastedGraphic-6.png>
>>>
>>> - Bert -
>>>
>>>
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>>> squeakland at squeakland.org
>>> http://lists.squeakland.org/mailman/listinfo/squeakland
>>>
>>>
>>
>>
>>
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>
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