How to clear a cluttered workspace in Pharo? - smalltalk

Question

In the Pharo MOOC there is a proposed challenge (section 2.15.2) that consists in taking a email address and getting the associated gravatar image, as a Morph object. I was able to do it, by running the following code in the playground:
| url email |
email := 'stephane.ducasse#inria.fr'.
url := 'http://www.gravatar.com/avatar/', (MD5 hashMessage: email) hex asString , '.jpg'.
(ZnEasy getJpeg: url) asMorph openInHand.
Now the problem is, I could not figure out how to properly clean my workspace of all the objects downloaded:
As you can see, now I have the image from the url (from a previous botched attempt where I did url asMorph openInHand without getting the jpg with ZnEasy first), and several lighthouse images (as every time I open the inspector a new one is generated).
I say properly clean because you can just exit Pharo without saving, and then open it again to have a clean workspace, but this is probably not ideal.
So far I tried to inspect the created objects, seeing they are instances of ImageMorph. Then in the associated methods I searched something including "erase", "del", "delete" or "clear", but could not find anything similar. These were the available methods for ImageMorph:
{ImageMorph>>#prepareForRotating.
ImageMorph>>#grabFromScreen.
ImageMorph>>#forwardDirection:.
ImageMorph>>#adoptPaneColor:.
ImageMorph>>#drawOnAthensCanvas:.
ImageMorph>>#extent:.
ImageMorph>>#setOptimalResizing.
ImageMorph>>#form:.
ImageMorph>>#shouldFlex.
ImageMorph>>#forwardDirection.
ImageMorph>>#resize:.
ImageMorph>>#areasRemainingToFill:.
ImageMorph>>#heading.
ImageMorph>>#imageExport.
ImageMorph>>#defaultImage.
ImageMorph>>#rotationDegrees.
ImageMorph>>#borderStyle:.
ImageMorph>>#opacityString.
ImageMorph>>#setDirectionFrom:.
ImageMorph>>#rotationDegrees:.
ImageMorph>>#borderWidth:.
ImageMorph>>#isOpaque.
ImageMorph>>#image:.
ImageMorph>>#readFromFile.
ImageMorph>>#drawOn:.
ImageMorph>>#basicExtent:.
ImageMorph>>#form.
ImageMorph>>#withSnapshotBorder.
ImageMorph>>#wantsRecolorHandle.
ImageMorph>>#changeOpacity.
ImageMorph>>#initialize.
ImageMorph>>#addCustomMenuItems:hand:.
ImageMorph>>#isOpaque:.
ImageMorph>>#releaseCachedState.
ImageMorph>>#color:}
I also tried to execute garbageCollect, and just click the images and press Delete.

Answer 1

After opening them in the hand, you have positioned them in the world. If you inspect the world, you'll see there are a number of ImageMorphs. You want to exclude the Pharo logo. If you inspect that, its extension tells you the logo is locked.
World submorphs select: [ :m |
m class = ImageMorph and: [
m isLocked not ] ]
thenDo: [ :m | m delete ]

Answer 2

Another way, which is not so practical in this case, but is unique to smalltalk, is to use #allInstances. You can do
ImageMorph allInstances inspect
which returns all those images. in the raw view of the inspector, you can then send them #delete. Here that is not so practical, as the icons in the windows are also ImageMorphs, so you'll get a long list

Answer 3

Based on the above I used Playground to inspect the World subMorphs. This allows you to identify the unwanted images.
I then used (work SubMorphs at: n) delete to remove them individually. You need to track the indices as they may change each time an image is deleted.

Answer 4

To find all messages an object will understand, have a look at its class and at its superclasses. You will find delete in the Morph class, a superclass of ImageMorph.
Try executing this line by line:
| url email morph |
email := 'stephane.ducasse#inria.fr'.
url := 'http://www.gravatar.com/avatar/', (MD5 hashMessage: email) hex asString , '.jpg'.
morph := (ZnEasy getJpeg: url) asMorph.
morph openInHand.
morph delete.