Expression Tree Tutorial - Knowledge Base (KB)

Is there a simple method to convert a string (lambda expression) into an Action delegate?

I have a method that alters an "Account" object based on the action delegate passed into it:...public static void AlterAccount(string AccountID, Action<Account> AccountAction) { Account someAccount = accountRepository.GetAccount(AccountID); AccountAct...

How can I parse random strings into expression trees in C#?

In a project that I'm working on I have to work with a rather weird data source. I can give it a "query" and it will return me a DataTable. But the query is not a traditional string. It's more like... a set of method calls that define the criteria that I ...

C# assistance with parsing my own expression tree

I have the following code. I constructed an expression tree and I am stuck parsing it to find the result ...You will find the details within my code...public enum OpertaionType { add, sub, div, mul} public class Node { public Node(Node lhs, Node rhs...

Query filter expression tree parser

I am looking for a parser that can operate on a query filter. However, I'm not quite sure of the terminology so it's proving hard work. I hope that someone can help me. I've read about 'Recursive descent parsers' but I wonder if these are for full-blown l...

What is the method for processing infix notation expressions?

I would like to parse boolean expressions in PHP. As in:...A and B or C and (D or F or not G) ...The terms can be considered simple identifiers. They will have a little structure, but the parser doesn't need to worry about that. It should just recognize t...

c# string expression to boolean expression converter

Is it possible to convert a string expression into a boolean condition?...For example, I get the following string:...var b = "32 < 45 && 32 > 20" ...I would like to create a ...bool... expression out of this and invoke it. The string representation is als...

How may parameters be sent into an Expression tree?

I am developing the parser for expressions like this: ...a1 + a2 + a3 > 0 and b <> "" or c = "source" ...I want to use expression tree and collect parameters (a1, a2..) while parsing expression. How to pass parameters into an Expression tree? ...Edit: I a...

Parser tree or expression tree

I'm doing a command line calculator, so I need to parse expressions....calc 2*(3+4)*5 ...I already have the scanner step done, returning a token's array. Now I'm at parser step. However I have no clue about how to do a parser/expression tree....This is al...

Building a Custom Expression Tree in Spirit:Qi (Without Utree or Boost::Variant)

First of all, if it is much easier using either Boost Variant or Utree, then I will settle with them, and i will try to solve my issues with them in another topic. However, i would very much like to be able to build a tree like i have below....Background,...