Can I load variables & functions from Octave script file into global scope from an if test?

Question

I have a script that performs a lot of computation on startup, and defines some functions, and I want to ensure it is all loaded when I run other scripts. I'm running Octave 5.1.0 configured for x86_64-w64-mingw32.

I initially tried call the script only if one of its variables didn't exist('varName'). That doesn't seem to work, so I marked a lot of the variables global, but they still aren't loaded into global, and the functions aren't either. The script works well if I call it from the top level of the REPL or the other script's top level (but not inside an if test). I also checked out other questions like octave: load many functions from single file.

This is what I want to do:

global all;
if (!exist('all'))
  prepareData
endif

I am wondering how to expose the global variables and functions in the prepareData script only the first time it is run.

score 1 · Answer 1 · answered Sep 27 '19 at 05:41

1

After going through the question writing process, it became clear to me that I can simply put the if (!exist('all')) into the original script to prevent it from loading the data multiple times. So now in the prepareData script I just put my expensive data loading inside this:

global all;
if (!exist('all') || length(all) < 1);
  # Expensive load calls
endif

and in the consuming script I can call simply:

prepareData;

# Happily use data

answered Sep 27 '19 at 05:41

Jonathan Johansen

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The additional `length(all) < 1` check is because the `global all;` gives the variable a dimension of `0x0` with value `[]`. – Jonathan Johansen Sep 27 '19 at 05:43
Note that `all` is name of a builtin function. – rahnema1 Sep 27 '19 at 17:16

Can I load variables & functions from Octave script file into global scope from an if test?

1 Answers1