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digitalmars.D.bugs - [Issue 4348] New: std.container.SList append

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4348

           Summary: std.container.SList append
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc


--- Comment #0 from bearophile_hugs eml.cc 2010-06-19 12:52:03 PDT ---
This shows how you can append to a std.container.SList:

import std.container: SList;
void main() {
    auto l = SList!int(1, 2);
    l.insertAfter(l[], 3);
}


But the standard D syntax too can be supported, despite it's O(n):

import std.container: SList;
void main() {
    auto l = SList!int(1, 2);
    l ~= 3;
}


(The member function "insertFront" might be named "prepend", that is shorter ,
equally readable and contains no upper case letters).

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Jun 19 2010
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4348


Andrei Alexandrescu <andrei metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrei metalanguage.com


--- Comment #1 from Andrei Alexandrescu <andrei metalanguage.com> 2010-06-19
14:51:02 PDT ---
~= is only for containers that can implement it in time independent of the size
of the container. Writing s.insertAfter(s[], value) hints the user that the
cost is higher (i.e. proportional to the length of s[]).

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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--- Comment #2 from bearophile_hugs eml.cc 2010-06-19 15:20:42 PDT ---
Answer to Comment 1: thank you for your answer, I didn't know about this rule.

In arrays the append can require a full array copy, so it can be O(n), but it's
(hopefully) O(1) on amortized time.

If this rule is present and well established then you can close this bug report
(the suggestion about the "prepend" name is for you, but you can ignore it if
you don't like it).

Another possibility is to find a compromise: instead of writing something hairy
like:
s.insertAfter(s[], value)
You can use:
s.linearAppend(value)
That is less noisy and equally clear in its complexity :-)

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prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=4348


bearophile_hugs eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |WONTFIX


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Jun 20 2010