Performance improvements: Optimize built-in functions name checking and use ConcurrentDictionary<string, WeakReference<LogicalExpression>> at caching

[gumbarros]

Before:

After:
(At IL it's optimized by string size)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 96.00000% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 74.01%. Comparing base (c5fcc0e) to head (c745739).

❗ Current head c745739 differs from pull request most recent head 10d3d7e. Consider uploading reports for the commit 10d3d7e to get more accurate results

Files	Patch %	Lines
src/NCalc/Domain/EvaluationVisitor.cs	96.72%	1 Missing and 1 partial ⚠️
src/NCalc/Expression.cs	94.87%	0 Missing and 2 partials ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##           master     #114      +/-   ##
==========================================
- Coverage   74.30%   74.01%   -0.30%     
==========================================
  Files          20       20              
  Lines        4480     4433      -47     
  Branches      274      255      -19     
==========================================
- Hits         3329     3281      -48     
  Misses       1021     1021              
- Partials      130      131       +1     

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[ThomasHambach]

Thanks for the contribution @gumbarros

You mention performance improvements, did you run any tests to confirm it runs faster?

[gumbarros]

Thanks for the contribution @gumbarros

You mention performance improvements, did you run any tests to confirm it runs faster?

No, just checked the IL and checked the unit test of concurrency to see if everything is alright. Do you know how can I do a Benchmark to compare two NCalc versions?

[Bykiev]

Do you know how can I do a Benchmark to compare two NCalc versions?

You can use https://github.com/dotnet/BenchmarkDotNet library to measure performance with existing NuGet package

[yallie]

I'm sorry guys, I'm still feeling sick a bit and can't function properly.
I was going to merge all PRs and release it as a new version.
But looks like recent PRs have conflicts in the generated code due to grammar changes.
Could you give me a hand resolving the conflicts please?
Perhaps it's the matter of regenerating the parser/lexer classes.

PS. @gumbarros, @lucaschimweg — thanks a lot for your contributions! 🚀

[gumbarros]

Ready to merge