Working with expression AST:s

Posted by Marcus on Stack Overflow See other posts from Stack Overflow or by Marcus
Published on 2010-04-12T14:56:53Z Indexed on 2010/04/12 15:13 UTC
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ast

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expression

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design-patterns

Hi,

Is there any best practice when working with AST:s? I have a parsed expression AST. ConstantExpression, BinaryExpression etc. I want to populate a GUI-dialog with information from the AST, and it's here where I get kinda confused because my code gets pretty messy.

Example:

expression = "Var1 > 10 AND Var2 < 20"

I want to populate two textboxes with value 10 resp. 20 from the AST. What I'm doing now is a recursive method that checks for correct child expression-types (with .Net Is-operator) and acts accordingly and the code is really "smelly" :)

Is there any design pattern, like Visitor or such, that makes this somewhat easier/more readable/maintainable ?

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