About

What's going on here?

This site uses Microsoft's "Roslyn" CTP to implement section 7.16.2 of the C# language specification, namely the translation of C# query expressions into the equivalent chain of method invocations.

This is purely a syntactic mapping; it can be performed on a query expression in absolute isolation. For example, from person in People select person.Age can be translated into People.Select(person => person.Age) without any knowledge of what Person represents or what Age might represent for a person found within it. Even Select doesn't have to be the usual extension method.

The specification defines six explicit steps to apply to perform the transformation, which I aim to implement faithfully. I have added the further step of removing unnecessary parentheses from expressions; although this is not explicitly included in the specification, the examples given do remove parentheses where they are not necessary. A final step, which the C# compiler does not have to worry about, will be to format the output code nicely.

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