🚀 go-pugleaf

Andrew Koenig (ark@research.att.com) wrote:
: In article <311FEBD8.7305@cnj.digex.net> Aristotle <johndc@cnj.digex.net> writes:

: > Does anyone have any tips on how to go about writing an expression 
: > evaluator(one complex enough to handle Trig. functions). I am writing a 
: > program that uses expression and I would like to have the user be able to 
: >  enter their own expressions and have my program implement them. Any help 
: >  would be appreciated. Thanks in advance!

: Read ``The UNIX Programming Environment'' by Kernighan and Pike (Prentice-Hall).

The code for the calculator described in this bible is available at
ftp://plan9.att.com/csrc/hoc.bundle.Z

-taj

On 15 Feb 1996, Taj Khattra wrote:

> Andrew Koenig (ark@research.att.com) wrote:
> : In article <311FEBD8.7305@cnj.digex.net> Aristotle <johndc@cnj.digex.net> writes:
> 
> : > Does anyone have any tips on how to go about writing an expression 
> : > evaluator(one complex enough to handle Trig. functions). I am writing a 
> : > program that uses expression and I would like to have the user be able to 
> : >  enter their own expressions and have my program implement them. Any help 
> : >  would be appreciated. Thanks in advance!
> 
> : Read ``The UNIX Programming Environment'' by Kernighan and Pike (Prentice-Hall).
> 
> The code for the calculator described in this bible is available at
> ftp://plan9.att.com/csrc/hoc.bundle.Z
> 

I have a expression evaluator written in Turbo Pascal, it is part of a 
numerical solver I wrote with Staale Schumacher years back. It is as far 
as I can remember quite stable and safe. You can have it if you want it. 
If I don't remember wrong it has some ability to "define" functions aswell.

Simen Svale Skogsrud

Aristotle <johndc@cnj.digex.net> wrote:
>
> Does anyone have any tips on how to go about writing an expression 
> evaluator(one complex enough to handle Trig. functions). I am writing a 
> program that uses expression and I would like to have the user be able to 
>  enter their own expressions and have my program implement them. Any help 
>  would be appreciated. Thanks in advance!
> 		
> 				John M. "Aristotle" De Cristofaro


I have an expression evaluator written in C based on Polish notation.

It was primarily designed for normal mathemtical functions such as
add, subtract, multiply and divide.  It does, however, manager
brackets - using recursion.

It could be modified to include further functions.

Email me if you want the source code.


Malcolm Smith
mjsmith@mpx.com.au

In article <4g19rq$288@inferno.mpx.com.au>
           mjsmith@mpx.com.au "Malcolm Smith" writes:

> 
> I have an expression evaluator written in C based on Polish notation.
> 
> It was primarily designed for normal mathemtical functions such as
> add, subtract, multiply and divide.  It does, however, manager
> brackets - using recursion.
> 

That's cheating isn't it ?  r.p.n is a doddle to code :)

If you are doing this in Pascal (First in your newsgroups line) then check
out SWAG, which has several infix parsers (how you write math. expressions
in your code).

SWAG is big though, but it is a superlative programming resource.  It is
accessible from the clpb mini-FAQ (sorry, con't remember the swag url)
that FAQ is also on the Web at:

http://www.geocities.com/TimesSquare/2678/clpbfaq.html
-- 
* TQ 1.0 * The 'Just So Quotes'.
"Waiter, there's no fly in my soup!"
    	-- Kermit the frog

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a basic 
spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found I 
still have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a basic 
spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found I 
still have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a basic 
spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found I 
still have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De CristofaroAristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a basic 
spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found I still 
have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De CristofaroAristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a basic 
spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found I still 
have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De CristofaroAristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a basic 
spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found I still 
have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De CristofaroAristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a basic 
spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found I still 
have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a
basic spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found 
I still have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle wrote:
> 
> Does anyone have any tips on how to go about writing an expression
> evaluator(one complex enough to handle Trig. functions). I am writing a
> program that uses expression and I would like to have the user be able to
>  enter their own expressions and have my program implement them. Any help
>  would be appreciated. Thanks in advance!
> 
>                                 John M. "Aristotle" De Cristofaro

Borland Pascal-3 (if you can remember that far back) included
source code for what they called MicroCalc, sample code for a
basic spread sheet. In that code was a reasonably good function 
interpreter and evaluator which I have used often with good results. 
It will handle fairly complicated expressions as long as parens are
not to deep. In digging through my stack of old 5.25 DDs I found 
I still have it. If you are interested, I would be happy to make it
available to you.

straty@bldrdoc.gov

Aristotle <johndc@cnj.digex.net> wrote:
> Does anyone have any tips on how to go about writing an expression 
> evaluator(one complex enough to handle Trig. functions). I am writing a 

There is information of Turbo Pascal experssion parsing in the
inevitable

 93045 Jan 1 09:31 ftp://garbo.uwasa.fi/pc/link/tsfaqp.zip
 tsfaqp.zip Common Turbo Pascal Questions and Timo's answers

   All the best, Timo

P.S. Please let's cut back on the crossposting a bit. Followups
redirected to news:comp.lang.pascal.borland.

....................................................................
Prof. Timo Salmi   Co-moderator of news:comp.archives.msdos.announce
Moderating at ftp:// & http://garbo.uwasa.fi archives  193.166.120.5
Department of Accounting and Business Finance  ; University of Vaasa
ts@uwasa.fi http://uwasa.fi/~ts BBS 961-3170972; FIN-65101,  Finland

Have you tried LEX and YACC? The tools could be an overkill but for more 
complex parsing stuff, they will save you time.

Anh

In article <31251AAF.2D0B@harrier.bldrdoc.gov>, "G. C. Straty" <straty@harrier.bldrdoc.gov> writes:
> Aristotle wrote:
>> 
>> Does anyone have any tips on how to go about writing an expression
>> evaluator(one complex enough to handle Trig. functions). I am writing a
>> program that uses expression and I would like to have the user be able to
>>  enter their own expressions and have my program implement them. Any help
>>  would be appreciated. Thanks in advance!
>> 

No no no, you're doing this all wrong!  The correct way to write an 
expression evaluator is with QBASIC.  Observe:

    PRINT "Enter an expression:"
    INPUT E$
    OPEN "TEMP.BAS" FOR OUTPUT AS #1
    PRINT #1, "PRINT " + E$
    PRINT #1, "RUN "+CHR$(34)+"THISPROG.BAS"+CHR$(34)
    CLOSE #1
    RUN "TEMP.BAS"

Jeez guys, I don't know why your complicating the issue with things like 
parsing and recursion.  Go figure.
 
-Sam McGrath

[insert smiley face here.  I refuse to.]