Linq.Expression.Optimizer
Lightweight optimizer of System.Linq.Expression expressions. Just basic boolean algebra and reductions, constant and tuple/anonymous type eliminations. For side-effect free Expressions. No compilation-subjective optimizations. This is meant to be used with expressions that are not compiled but transferred to other domain.
Supported frameworks: Net 3.5, Net 4.5-... (and Mono), .NET Standard 1.6 (so also .NET Core)
Supported optimizations
Example as a quote. There are various other cases also.
- Replace constants comparisons:
3 < 4 -> true - Remove anonymous types:
new AnonymousObject(Item1 = x, Item2 = "").Item1 --> x - Cut not used condition:
if false then x else y -> y - Remove not:
not(false) -> true - Binary tree balancing:
a or (b or (c or (d or (e or (f or (g or h)))))) -> ((a or b) or (c or d)) or ((e or f) or (g or h)) - Captured closure constant ("free variable") evaluation:
y = 3 and (y + x) -> (3 + x) - Execute simple math:
5 * 3 -> 15 - Boolean algebra reductions:
- gather
(x or y) and (x or z) -> x or (y and z) - identity
false or y -> y - annihilate
true or x -> true - absorb
x and (x or y) -> x - idempotence
y or y -> y - complement
x and not(x) -> false - doubleNegation
not(not(y)) -> y - deMorgan
not(x) and not(y) -> not(x or y)
- gather
Background
This is a side-track from SQLProvider, excelent tool that is kind of OR-mapper with auto-generated objects, so it compiles any databases to .NET-language, and works fast on design time in Visual Studio or other editors.
But I needed better SQL-queries. So this optimses .NET LINQ-expressions. These expressions were not ment to be compiled so Nessos LinqOptimizer was not the right tool. I thought that .NET would optimize these automatically, but no.
Read the Getting started tutorial to learn more.
Documentation: http://thorium.github.io/Linq.Expression.Optimizer
Maintainer(s)
If you want more optimizations, please feel free to send PRs!