Marc,
try this here:
if get(g:, 'purescript_update_path')
call PurescriptUpdatePath()
endif
You can omit the v:false in get(), see `:help get()` for more details.
g:, w: and b: return the global, window-local, and buffer-local dictionary,
respectively. See `:help g:` for more details. For example, if you run `:echo g:`
in the command-line it will print all the global variables as a dictionary. When
we pass g:, b: or w: to get(), we essentially use the following overload:
get({dict}, {key} [, {default}])