I don't much like WriteStream on: String empty.
If String empty is implemented as answering a literal, and WritStream
implemented to become the grown contents as it originally did in st80 and
could also do in Squeak now that we have a fast become, we take the risk to
modify the literal...
String new better express our intention, we want a new substring.
Also, contents does not necessarily answer a copy, it could answer the
verbatim contents if full. So i hope that resetContents would perform the
copy, but that's far from certain without seing code. We thus risk to have
substrings sharing identity, and overwrite previous substring...
Note that we can also efficiently search index of any of a character set,
starting at a given index in case of byte string...

Le mar. 4 juin 2019 à 21:34, <commits at source.squeak.org> a écrit :

> Chris Muller uploaded a new version of Collections to project The Inbox:
> http://source.squeak.org/inbox/Collections-cmm.836.mcz
>
> ==================== Summary ====================
>
> Name: Collections-cmm.836
> Author: cmm
> Time: 4 June 2019, 2:34:30.820747 pm
> UUID: 95d228d9-2fda-4e35-9665-d1daf90cbd99
> Ancestors: Collections-cmm.835
>
> - Move utility methods of Collection to 'utilities'.
> - #joinSeparatedBy: is useful even for non-SequenceableCollections.
> - Speed up String>>#subStrings:.
>
> =============== Diff against Collections-cmm.835 ===============
>
> Item was changed:
> + ----- Method: Collection>>asCommaString (in category 'utilities') -----
> - ----- Method: Collection>>asCommaString (in category 'printing') -----
>   asCommaString
>         "Return collection printed as 'a, b, c' "
> +       ^ self joinSeparatedBy: ', '!
> -
> -       ^String streamContents: [:s | self asStringOn: s delimiter: ', ']
> -               !
>
> Item was changed:
> + ----- Method: Collection>>asCommaStringAnd (in category 'utilities')
> -----
> - ----- Method: Collection>>asCommaStringAnd (in category 'printing') -----
>   asCommaStringAnd
>         "Return collection printed as 'a, b and c' "
>
>         ^String streamContents: [:s | self asStringOn: s delimiter: ', '
> last: ' and ']
>                 !
>
> Item was changed:
> + ----- Method: Collection>>asStringOn:delimiter: (in category
> 'utilities') -----
> - ----- Method: Collection>>asStringOn:delimiter: (in category 'printing')
> -----
>   asStringOn: aStream delimiter: delimString
>         "Print elements on a stream separated
>         with a delimiter String like: 'a, b, c'
>         Uses #asString instead of #print:."
>
>         self do: [:elem | aStream nextPutAll: elem asString]
>                 separatedBy: [aStream nextPutAll: delimString]!
>
> Item was changed:
> + ----- Method: Collection>>asStringOn:delimiter:last: (in category
> 'utilities') -----
> - ----- Method: Collection>>asStringOn:delimiter:last: (in category
> 'printing') -----
>   asStringOn: aStream delimiter: delimString last: lastDelimString
>         "Print elements on a stream separated
>         with a delimiter between all the elements and with
>         a special one before the last like: 'a, b and c'.
>         Uses #asString instead of #print:
>
>         Note: Feel free to improve the code to detect the last element."
>
>         | n sz |
>         n := 1.
>         sz := self size.
>         self do: [:elem |
>                 n := n + 1.
>                 aStream nextPutAll: elem asString]
>         separatedBy: [
>                 aStream nextPutAll: (n = sz ifTrue: [lastDelimString]
> ifFalse: [delimString])]!
>
> Item was changed:
> + ----- Method: Collection>>histogramOf: (in category 'utilities') -----
> - ----- Method: Collection>>histogramOf: (in category 'converting') -----
>   histogramOf: aBlock
>
>         ^ self collect: aBlock as: Bag!
>
> Item was added:
> + ----- Method: Collection>>join (in category 'utilities') -----
> + join
> +       "Example: #(H e l l o W o r l d) join = 'HelloWorld'."
> +       ^ self joinSeparatedBy: String empty!
>
> Item was added:
> + ----- Method: Collection>>joinSeparatedBy: (in category 'utilities')
> -----
> + joinSeparatedBy: aString
> +       "Returns a string, which is a concatenation of each element's
> string representation separated by another string."
> +       ^ String streamContents:
> +               [ : stream | self asStringOn: stream delimiter: aString ]!
>
> Item was changed:
> + ----- Method: Collection>>topologicallySortedUsing: (in category
> 'utilities') -----
> - ----- Method: Collection>>topologicallySortedUsing: (in category
> 'converting') -----
>   topologicallySortedUsing: aSortBlock
>         "Answer a SortedCollection whose elements are the elements of the
>         receiver, but topologically sorted. The topological order is
> defined
>         by the argument, aSortBlock."
>
>         | aSortedCollection |
>         aSortedCollection := SortedCollection new: self size.
>         aSortedCollection sortBlock: aSortBlock.
>         self do: [:each | aSortedCollection addLast: each].     "avoids
> sorting"
>         ^ aSortedCollection sortTopologically
>   !
>
> Item was removed:
> - ----- Method: SequenceableCollection>>join (in category 'converting')
> -----
> - join
> -       "Example: #(H e l l o W o r l d) join = 'HelloWorld'.  "
> -
> -       ^ self joinSeparatedBy: ''!
>
> Item was removed:
> - ----- Method: SequenceableCollection>>joinSeparatedBy: (in category
> 'converting') -----
> - joinSeparatedBy: aSeparator
> -       "Returns a string, which is a concatenation of each element's
> string representation separated by another string."
> -
> -       ^ String streamContents: [:stream |
> -               self
> -                       do: [:ea | stream nextPutAll: ea asString]
> -                       separatedBy: [stream nextPutAll: aSeparator
> asString]]!
>
> Item was changed:
>   ----- Method: String>>subStrings: (in category 'converting') -----
>   subStrings: separators
> +       "Answer an array containing the substrings in the receiver
> separated by the elements of separators."
> -       "Answer an array containing the substrings in the receiver
> separated
> -       by the elements of separators."
>         | char result sourceStream subString |
> +       (separators isString or:
> +               [ separators allSatisfy:
> +                       [ : element | element isCharacter ] ]) ifFalse: [
> ^ self error: 'separators must be Characters.' ].
> -       #Collectn.
> -       "Changed 2000/04/08 For ANSI <readableString> protocol."
> -       (separators isString or:[separators allSatisfy: [:element |
> element isCharacter]]) ifFalse:
> -               [^ self error: 'separators must be Characters.'].
>         sourceStream := ReadStream on: self.
>         result := OrderedCollection new.
> +       subString := WriteStream on: String empty.
> +       [ sourceStream atEnd ] whileFalse:
> +               [ char := sourceStream next.
> +               (separators includes: char)
> +                       ifTrue:
> +                               [ subString isEmpty ifFalse:
> +                                       [ result add: subString contents.
> +                                       subString resetContents ] ]
> +                       ifFalse: [ subString nextPut: char ] ].
> +       subString isEmpty ifFalse: [ result add: subString contents ].
> -       subString := String new.
> -       [sourceStream atEnd]
> -               whileFalse:
> -                       [char := sourceStream next.
> -                       (separators includes: char)
> -                               ifTrue: [subString notEmpty
> -                                               ifTrue:
> -                                                       [result add:
> subString copy.
> -                                                       subString :=
> String new]]
> -                               ifFalse: [subString := subString , (String
> with: char)]].
> -       subString notEmpty ifTrue: [result add: subString copy].
>         ^ result asArray!
>
>
>
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