Expression trees in C#

on YouTube ↗48m

" summary

Explains what C# expression trees are, shows manual construction with System.Linq.Expressions and compiling them to IL, and benchmarks calling a private method: reflection (slow) → cached MethodInfo → Delegate.CreateDelegate → compiled expression (fastest), with dynamic about 20x slower. Builds a generic three‑quarters operator via compiled expressions, a small calculator DSL parsed with Sprache into Expression trees and compiled, and an ExpressionVisitor that rewrites sin to cos — all working as demonstrated.

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" chapters (9)

1. 0:00Intro
2. 0:11Expression Trees in C#
3. 5:36Expression Tree describes the structure of an expression
4. 6:51Constructing Expression Trees Manually
5. 14:07Optimizing Reflection Heavy Code
6. 19:54Implementing Generic Operators
7. 25:40Parsing DSLs into Expression Trees
8. 36:41Preserving Source Code in Assertions
9. 43:12Transpiling Code into a Different Language

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