Equation parser - where did I see it?

[trashman.horlicks]

Hi,
A few months ago, I saw an equation parser, written in c#, and using
regular expressions (I think!), but now I cannot recall where I saw
it- if anyone saw anything like this, could they please post the url?

From memory,

the parser not only dealt with operator precedence, but also the use
of brackets, so that any complicated expession could be re-written as
an equation that could be read from left-to-right, as a simple
sequence of sub-equations using basic operators, +,-,/,*

The reason why I ask is that I am anticipating user input into a form
as a string, and I need to convert it into
an equation. The user inputted expression could be something like (a+
(b-d)*(e-c))/f so I need to find a way to parse it.

TIA

Paul

 

[ClayB]

I doubt if this is what you saw earlier, but here is a link to a
TRINUG usergroup meeting presentation that describes making a
WindowsForm DataGridView into Excel. It has a very simple/minimal C#
calculation engine defined that handles precedence and parentheses.
Maybe it will be of help in your task.

http://www.trinug.org/Portals/0/DataGridViewCustomization - Oct '06.zip

=======================
Clay Burch
Syncfusion, Inc.

 

[Fabrizio]

Maybe this: http://www.osix.net/modules/article/?id=761
Or this: http://www.osix.net/modules/article/?id=776

HTH
Fabrizio

 

[ClayB]

One other comment is that there are commercial products that would
allow you to write code that would input a string like (a+(b-c)*(e-c)/
f, identify the unknowns a,b,c,d,e,f, and then allow your user to
input the values for these unknowns and finally compute the entered
expression.

===============================
Clay Burch
Syncfusion, Inc.

 

[Guest]

Are you looking for this ?

http://www.codeproject.com/csharp/RPN_ExpressionParser.asp

Regards,

Bart

 

[trashman.horlicks]

Are you looking for this ?

http://www.codeproject.com/csharp/RPN_ExpressionParser.asp

Regards,

Bart

They weren't what I saw, but they're still very useful!

Thanks a million for the quick replies, they may just save my life

Best wishes

Paul

 

[William Stacey [C# MVP]]

Taking a dependancy on powershell may not work for you, but would allow you
to invoke any expression you can do on the command line and also can use any
..net lib (i.e. system.math) or external lib. And you can script your host
with it too if needed.

--
William Stacey [C# MVP]
PCR concurrency library: www.codeplex.com/pcr
PSH Scripts Project www.codeplex.com/psobject


| Hi,
| A few months ago, I saw an equation parser, written in c#, and using
| regular expressions (I think!), but now I cannot recall where I saw
| it- if anyone saw anything like this, could they please post the url?
| >From memory,
| the parser not only dealt with operator precedence, but also the use
| of brackets, so that any complicated expession could be re-written as
| an equation that could be read from left-to-right, as a simple
| sequence of sub-equations using basic operators, +,-,/,*
|
| The reason why I ask is that I am anticipating user input into a form
| as a string, and I need to convert it into
| an equation. The user inputted expression could be something like (a+
| (b-d)*(e-c))/f so I need to find a way to parse it.
|
| TIA
|
| Paul
|