String>> isValidBinary ^self allSatisfy: [:each | each = $0 or: [each = $1]] binaryToDecimal "The caller should ensure that self isValidBinary before calling this." ^self inject: 0 into: [:acc :each | acc*2 + (each codePoint - $0 codePoint)] On Mon, 27 Apr 2020 at 06:05, Roelof Wobben via Pharo-users <pharo-users@lists.pharo.org> wrote:

Hello,

I have to make some code that convert a binary to a decimal and im not allowed to use the convert methods that Pharo has.

So I have written this :

decimalFromBinary: aString | result isValid | isValid = self isValidBinary: aString. isValid ifTrue: [ result := 0. aString reverse withIndexDo: [ :digit :index | result := result + (digit digitValue * (2 raisedTo: index - 1)) ]. ^ result ] ifFalse: [ ^ nil ]

isValidBinary: aString ^ aString allSatisfy: [ :c | c = 0 or: [ c = 1 ] ]

but on the first method I see a message that the temp variables are read before written. and the second one I see a message that I use a or instead of searching literals.

Where did I think wrong here ?

Roelof