checkout some https://github.com/dadhi/FastExpressionCompiler and DryIoC

[dzmitry-lahoda]

it has some tree to String stuff and complex trees

[zspitz]

Thank you for the link. The magic happens in the ToCSharpPrinter class and in the ToExpressionPrinter class. It may be interesting to extract these into a separate project and see how they perform in unit tests against this library.

[dzmitry-lahoda]

@dadhi

[dadhi]

Wow, wow :) this lib does much more than mine.. great job. For now, mine are more of the diagnostics helpers to the compiler (though I have plans to use C# output for the code gen later).

@zspitz Btw, do you handle the expressions with the block on the right side of the assignment, or inside the ternarary - I mean the cases where in C# you must have an expression but the Expression trees allow the blocks?

[zspitz]

@dadhi Thanks for the kind words.

Btw, do you handle the expressions with the block on the right side of the assignment, or inside the ternarary - I mean the cases where in C# you must have an expression but the Expression trees allow the blocks?

I try. I was under the (apparently mistaken) impression that C# supports the , operator, which (in other C-style languages) has the same semantics as a BlockExpression -- multiple statements, and the last expression becomes the value of the entire expression. I will have to rethink this.

But my goal is a little different -- I'm not aiming for code that is completely syntactically correct, but rather a string that uses C# constructs as much as possible to represent an expression tree. So, for example, VB.NET doesn't have a standalone block structure; the grouped statements are always in the context of some other syntax -- For Each, or a method, or an If...Then. So if I have a BlockExpression without any other context, I represent it as a Block ... End Block syntax, which (I think) gets the point across, even if it isn't syntactically valid.

There will always be expressions that can't be represented in a given language; C# is the best in this regard, but aside from BlockExpressions there's also unsupported dynamic operations -- DeleteIndexBinder and DeleteMemberBinder -- which other languages support.

And so, it might be better to render BlockExpression in an expression context, as standard curly-braced blocks.

[dadhi]

Interesting, thanks for the doc link. My goal is to provide a compilable C# as much as possible, as I plan the code-gen and also extract the result output to the tests.