How do you link up the BNF definition with the parse statement?
I can't seem to find any simple examples. Thanks!
REBOL [
Title: "Differentiator"
Purpose: {
differentiates an algebraic function
differentiate "x**2" returns "2*x**1"
}
]
differentiate: function [str [string!]] [result] [
result: ""
factor: ["x**" digit]
digit: charset "0123456789"
parse str [
factor (result: join result [ digit "*x**" digit - 1 ] ) ;this
doesn't work
]
return result
]
print [differentiate "x**2"]
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Sunday, February 06, 2000 3:25 AM
Subject: [REBOL] Re: [Rebol_New] symbol manipulation
> [EMAIL PROTECTED] wrote (on Rebol_New):
> > I'd like to learn how to do symbolic differentiation and parse roman
> numerals to get arabic numbers. I've read the docs, but nothing sinks in.
I
> believe I need to use the dialog method. Does anybody know how to do
these?
>
> My rather boring Roman numerals converter implementation is attached.
>
> Andrew Martin
> Partying like it's MIM...
> ICQ: 26227169
> http://members.xoom.com/AndrewMartin/
> -><-
>
>
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>
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