AoC 2022, day 10 (smalltalk)

#!/usr/local/bin/gst -q

Collection extend [
    apply: method  [ ^self collect: [:x | x perform: method] ]
    sum            [ ^self inject: 0 into: [ :a :b | a + b ] ]
]

"
| Mainline
"
" Build a list of increment events to regX "
events := stdin lines contents gather: [ :line |
              " addx VALUE adds (0, VALUE), delaying by one cycle "
              " noop adds (0), a cycle of adding nothing "
              line substrings apply: #asNumber
          ].

" Build table of the values of regX for each time "
regX := OrderedCollection with: 1.
events inject: 1 into: [:a :b | regX add: (a + b)].

" Part one is the sum of (time * regX) at these set times "
'Part 1: ' display.
((20 to: 220 by: 40) collect: [:time | time * (regX at: time)]) sum displayNl.

" Part 2 involves outputing a # pixel when regX is inside scan window "
'Part 2:' displayNl.
regX keysAndValuesDo: [ :time :val |
    (((time - 1) \\ 40 - val) abs <= 1 ifTrue: [$#] ifFalse: [$ ]) display.
    (time \\ 40) = 0 ifTrue: [ stdout nl ].     " newline every 40 "
]