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Intern string by amos402 · Pull Request #1254 · pythonnet/pythonnet

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@amos402

What does this implement/fix? Explain your changes.

Use the intern strings map to const strings instead of creating temporary strings everytimes.

Checklist

Check all those that are applicable and complete.

  • Make sure to include one or more tests for your change
  • If an enhancement PR, please create docs and at best an example
  • Add yourself to AUTHORS
  • Updated the CHANGELOG

lostmsu

Comment on lines +1 to +4

<#@ template debug="true" hostSpecific="true" #>
<#@ output extension=".cs" #>
<#
string[] internNames = new string[]

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Why use a template generator, when you can simply get internNames from reflection? It looks like unnecessary complication.

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Two reasons make this scenario happened.

  1. You need to make sure the string is a c# intern string too to make code like this work without extra checking
const string s = "1";
switch (
    case "1":
        // both "1" point to the same string
       break;
  1. If you need (1), you have to make the internNames set on compile.
    Of course, if you don't (1), internNames can just set by using reflection from reading PyIdentities.

@codecov-io

Codecov Report

Merging #1254 into master will not change coverage.
The diff coverage is n/a.

Impacted file tree graph

@@           Coverage Diff           @@
##           master    #1254   +/-   ##
=======================================
  Coverage   86.25%   86.25%           
=======================================
  Files           1        1           
  Lines         291      291           
=======================================
  Hits          251      251           
  Misses         40       40
Flag Coverage Δ
setup_linux 64.94% <ø> (ø)
setup_windows 72.50% <ø> (ø)

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lostmsu

@lostmsu

@amos402 did you have a chance to compare benchmarks on your branch with InteropString.GetManagedString replaced by Runtime.GetManagedString?

@amos402

https://gist.github.com/amos402/8decd54dee57fe654e098bc0b15c061a

CPU: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz
Python Version: 3.8.6

function origin intern-string without Intern.GetManagedString
get_doc 0.31777 (100.00%%) 0.18106 (56.98%%) 0.32203 (101.34%%)
get_attr_doc 0.3397 (100.00%%) 0.20156 (59.33%%) 0.34397 (101.26%%)
get_attr_doc_concat 0.34546 (100.00%%) 0.42619 (123.37%%) 0.34862 (100.91%%)

lostmsu