Defining a variable outside of a function in vim

Question

I would like to use a default argument that is defined outside of the function, for example:

let DEFAULT_FUNCTION_NAME = 'Toggle3'
func Run(function_name=DEFAULT_FUNCTION_NAME)
    echom function_name
endfunc

However, I get an error stating:

E121: Undefined variable: DEFAULT_FUNCTION_NAME

What would be the possible way to 'scope this' so that I can do something like the above?

Answer 1

Be explicit with the scope: declare it with a given scope

let s:var = ...

And then use s:var (or another scope). Note that s: in particular may not work since the default arguments are evaluated at call time!

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Edit: recent vim supports default function arguments, but I’ll leave this for older versions.

There are a couple of ways I can think of to handle defaults:

1. Pass a “special value” to represent not supplied, and fall back to the default
2. (The approach I see more often) document the use of a particular global variable, and use let var = get(g:, 'globalvar', default) to get the value or default for use.