From help-octave-request at bevo dot che dot wisc dot edu Tue Nov 13 14:26:52 2001
Subject: Modifying global variables from within functions
From: Roberto Hernandez <robher at adinet dot com dot uy>
To: help-octave at bevo dot che dot wisc dot edu
Date: Tue, 13 Nov 2001 17:26:28 -0300

Hello everyone,

I am trying to modify a global variable directly from within a function. 
  The solution I found is somewhat complicated for what I want. I was 
wondering if there's a better way to do it.

Here's the situation. The function "foo" has to accept a global variable 
name and a value and assign the value to the variable.

For example this function:

------------------------------
function foo(varName, newValue)
     eval(["global ",  varName]);

     if isnumeric(newValue)
         eval([varName, " = " , num2str(newValue), ";"])
     else
         eval([varName, " = \"" , newValue, "\";"])
     endif
endfunction
------------------------------

So I would call it this way:

------------------------------
octave:1> global a
octave:2> foo("a", 5)
ans = 5
octave:3> foo("a", "hello")
ans = hello
------------------------------

The previous example works fine. But if I want to do more complex 
operations inside the function "foo", then having to use "eval" and 
building lots of strings becomes annoying. It's easy to make mistakes 
and pretty bad for debugging.

The question is: Is there a better way to do this?

TIA,

-Roberto



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