Well my main run method looks like this:
run
| op | 
ram := self input.
in := ReadStream on: ram.
[ (op := in next) = 99 ] whileFalse: [ self processOpcode: op ].
^self at: 0.

ram is the array of integers.
in is a ReadStream on them which lets me process them in order.
They are both instance variables.

self input provides a clean copy of the program memory (the integer array).  I just used an array literal.  No file IO.

The main dispatch method is

processOpcode: op 

op = 1 ifTrue: [ ^self processAdd ].
op = 2 ifTrue: [ ^self processMultiply ].

and for illustration 

processAdd
| a b c |
a := self at: in next.
b := self at: in next.
self at: in next put: a+b

There are custom versions of at: and at:put: that compensate for zero based vs one based array indexing.

at: idx
^ram at: idx + 1

I hope this helps you out.

On Dec 17, 2019, at 6:59 AM, Roelof Wobben via Pharo-users <pharo-users@lists.pharo.org> wrote:


From: Roelof Wobben <r.wobben@home.nl>
Subject: how can I this refractor this so its more smalltalk
Date: December 17, 2019 at 6:59:28 AM PST
To: Any question about pharo is welcome <pharo-users@lists.pharo.org>


Hello,

My solution to day2 part1 is right this :

processData: instructions
    | opcode index firstNumber secondNumber placeToPut firstNumberIndex secondNumberIndex |
    index := 1.
    opcode := instructions at: index.
    [ opcode ~= 99 ]
        whileTrue: [ firstNumberIndex := instructions at: index + 1.
            secondNumberIndex := instructions at: index + 2.
            firstNumber := instructions at: firstNumberIndex + 1.
            secondNumber := instructions at: secondNumberIndex + 1.
            placeToPut := (instructions at: index + 3) + 1.
            opcode == 1
                ifTrue: [ instructions at: placeToPut put: firstNumber + secondNumber ].
            opcode == 2
                ifTrue: [ instructions at: placeToPut put: firstNumber * secondNumber ].
            index := index + 4.
            opcode := instructions at: index ].
    ^ instructions at: 1

so its ugly code

is there a way  I can this more the smalltalk way by using streams or something else.
if so, is there someone who can tell me or can let me see how to make this cleaner code

Roelof