Key () Pressed? (block)/Enabling Dropping

This article or section documents something not included in the current version of Scratch (3.0). It is only useful from a historical perspective.

In 1.4, the ability to drag and drop reporter block in the drop-down menu on the Key () Pressed? block was not available. To enable drag and dropping reporter block in the drop-down menu on the Key () Pressed? block, the %K argument's function in the System Browser had to be changed by editing the underlying Squeak code which controlled inputs.

Enabling

First, open the System Browser. Navigate to Scratch-Blocks → CommandBlockMorph → private → uncoloredArgMorphFor:

Replace the code with this:

uncoloredArgMorphFor: t1
	| t2 |
	t2 _ t1 at: 2.
	$a = t2 ifTrue: [^ AttributeArgMorph new choice: 'volume'].
	$b = t2 ifTrue: [^ BooleanArgMorph new].
	$c = t2 ifTrue: [^ ColorArgMorph new showPalette: true].
	$C = t2 ifTrue: [^ ColorArgMorph new showPalette: false].
	$d = t2 ifTrue: [^ ExpressionArgMorphWithMenu new numExpression: '0';
		 menuSelector: #directionMenu].
	$D = t2 ifTrue: [^ ExpressionArgMorphWithMenu new numExpression: '48';
		 menuSelector: #midiDrumMenu].
	$e = t2 ifTrue: [^ EventTitleMorph new].
	$f = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #mathFunctionNames;
		 choice: 'sqrt'].
	$g = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #graphicEffectNames;
		 choice: 'color'].
	$H = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #hookupSensorNames].
	$h = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #hookupBooleanSensorNames].
	$I = t2 ifTrue: [^ ExpressionArgMorphWithMenu new numExpression: '1';
		 menuSelector: #midiInstrumentMenu].
	$i = t2 ifTrue: [^ ExpressionArgMorphWithMenu new numExpression: '1';
		 menuSelector: #listIndexMenu].
	$k = t2 ifTrue: [^ ChoiceOrExpressionArgMorph new getOptionsSelector: #keyNames;
		 choice: 'space'].
	$L = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #listVarMenu].
	$l = t2 ifTrue: [^ ChoiceOrExpressionArgMorph new getOptionsSelector: #costumeNames;
		 choice: 'costume1'].
	$m = t2 ifTrue: [^ SpriteArgMorph new].
	$M = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #motorNames].
	$n = t2 ifTrue: [^ ExpressionArgMorph new numExpression: '10'].
	$N = t2 ifTrue: [^ ExpressionArgMorphWithMenu new numExpression: '60';
		 menuSelector: #noteSelector].
	$s = t2 ifTrue: [^ ExpressionArgMorph new stringExpression: ''].
	$S = t2 ifTrue: [^ ChoiceOrExpressionArgMorph new getOptionsSelector: #soundNames;
		 choice: 'pop'].
	$v = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #varNamesMenu;
		 choice: ''].
	$W = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #motorDirection].
	$x = t2 ifTrue: [^ ChoiceOrExpressionArgMorph new getOptionsSelector: #sceneNames;
		 choice: ''].
	$y = t2 ifTrue: [^ ExpressionArgMorphWithMenu new numExpression: '1';
		 menuSelector: #listIndexForDeleteMenu].
	^ ExpressionArgMorph new numExpression: '10'

Alternatively, scroll down to the line:

	$k = t2 ifTrue: [^ ChoiceArgMorph new getOptionsSelector: #keyNames;
		 choice: 'space'].

and replace ChoiceArgMorph with ChoiceOrExpressionArgMorph:

$k = t2 ifTrue: [^ ChoiceOrExpressionArgMorph new getOptionsSelector: #keyNames;
		 choice: 'space'].

Finally, Shift-Click R and select "save image for end-user" to save changes.

Warning:

Saving changes may cause irreversible damage to some copies of Scratch. If this happens, simply re-install Scratch.

Explanation

This patch functions by changing the input type. The basic input types include text boxes, text boxes with drop-down menus, drop-down menus which accept drop-ins, and drop-down menus which do not. By setting the input type to ChoceOrExpressionArgMorph, it is being set to a drop-down menu which accept drop-ins.

Using the modified block

There are many uses for this change. One use, namely emulating the (key pressed) block, is outlined here:

when gf clicked
set [n v] to [0]
forever
set [n v] to ((n) mod ((length of [keys v])+(1)))
change [n v] by (1)
if <key (item (n) of [keys v]) pressed?> then
set [key v] to (item (n) of [keys v])
end
end

when [space v] key pressed
say (key)// space

The list "keys" contains all the keys, namely:

1
2
3
4
5
6
7
8
9
0
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
space
up arrow
down arrow
left arrow
right arrow

This script makes projects like word processors very easy.