[Ifeffit] Ifeffit "print" command question

Bruce Ravel bravel at bnl.gov
Fri Dec 31 07:18:56 CST 2010

> I have recently downloaded Ifeffit for Mac OS X from your website.  I am
> hoping to be able to use it with EXAFS data as the FEFF6 website led me
> to your application.  I am currently working through the tutorial.
> However, every time I try to use the print command to make a literal
> string statement, all I get is 0.0000 back.  Example:
> print " the square root of ", number, " is ", sqrt(number)
> 0.0                         99.0000000 0.0000000 9.94987437
> print "Hi mom"
> 0.000000000
> Any thoughts?

My thought is RTM.


Ifeffit isn't really a proper language with a REPL in the sense that, say, 
bash or python or powershell is.  Ifeffit is a pretty singular of purpose 
object -- it is a tool for processing and analyzing certain kinds of data.  It 
just does that.

As the page from the manual explains, "print" is a way of evaluating 
expression.  "Hi mom" evaluates to 0.  So does " is ".  So does " the square 
root of ".

In the problem area of Ifeffit, "print" is an expression evaluator, not the 
parser/evaluator of a REPL.

Ifeffit> set a=2
Ifeffit> print a
Ifeffit> print sqrt(a)+atan(a**2)
Ifeffit> print "sqrt(a) + atan(a**2)"



 Bruce Ravel  ------------------------------------ bravel at bnl.gov

 National Institute of Standards and Technology
 Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2
 Building 535A
 Upton NY, 11973

 My homepage:    http://xafs.org/BruceRavel
 EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/

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