TbcParser - Math Expression Parser Component -- Code Crazy Community Board

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Date Posted: 22:28:38 03/24/01 Sat
Author: Ali Demir
Subject: TbcParser - Math Expression Parser Component

There is a handy Delphi component, TbcParser at <a rel=nofollow target=_blank href="http://www.bestcode.com">http://www.bestcode.com</a>

It comes with source code. It has Borland, COM, Java flavors. Parser Component parses and evaluates mathematical expressions given as strings at runtime. The expression can contain predefined or user defined variables and functions . When evaluation is requested, the parser compiles the expression into a parse tree. Further evaluations are made using this tree that represents the expression. The parser can optimize the tree by simplifying branches that evaluate to a constant.
 

An example expression is : LN(X)+SIN(10/2-5)

 
When parsed, this expression will be represented as: <LN(X)+0> since the SIN(10/2-5) is in fact SIN(0) which is a constant and is 0.

 
Thus, in a loop, if you change the value of X and ask for the value of the expression, it will be evaluated quite fast since SIN(10/2-5) is not dependent on X.

<a rel=nofollow target=_blank href="http://www.bestcode.com">http://www.bestcode.com</a>

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