6 files changed, 42 insertions, 51 deletions
diff --git a/runtime/autoload/provider/clipboard.vim b/runtime/autoload/provider/clipboard.vim
index e43f8fbb7a..9b79e5abec 100644
--- a/runtime/autoload/provider/clipboard.vim
+++ b/runtime/autoload/provider/clipboard.vim
@@ -1,6 +1,16 @@
 " The clipboard provider uses shell commands to communicate with the clipboard.
 " The provider function will only be registered if a supported command is
 " available.
+
+if exists('g:loaded_clipboard_provider')
+  finish
+endif
+" Default to FALSE.  Set by provider#clipboard#Executable() later.
+" To force a reload:
+"   :unlet g:loaded_clipboard_provider
+"   :runtime autoload/provider/clipboard.vim
+let g:loaded_clipboard_provider = 0
+
 let s:copy = {}
 let s:paste = {}
 let s:clipboard = {}
@@ -48,9 +58,6 @@ endfunction
 let s:cache_enabled = 1
 let s:err = ''
 
-" eval_has_provider checks the variable to verify provider status
-let g:provider#clipboard#enabled = 0
-
 function! provider#clipboard#Error() abort
   return s:err
 endfunction
@@ -123,12 +130,6 @@ function! provider#clipboard#Executable() abort
   return ''
 endfunction
 
-" Call this to setup/reload the provider
-function! provider#clipboard#Reload()
-  " #enabled is used by eval_has_provider()
-  let g:provider#clipboard#enabled = !empty(provider#clipboard#Executable())
-endfunction
-
 function! s:clipboard.get(reg) abort
   if type(s:paste[a:reg]) == v:t_func
     return s:paste[a:reg]()
@@ -195,4 +196,5 @@ function! provider#clipboard#Call(method, args) abort
   endtry
 endfunction
 
-call provider#clipboard#Reload()
+" eval_has_provider() decides based on this variable.
+let g:loaded_clipboard_provider = !empty(provider#clipboard#Executable())
diff --git a/runtime/autoload/provider/node.vim b/runtime/autoload/provider/node.vim
index 6413720605..dd2423fe2a 100644
--- a/runtime/autoload/provider/node.vim
+++ b/runtime/autoload/provider/node.vim
@@ -1,8 +1,7 @@
 if exists('g:loaded_node_provider')
   finish
 endif
-let g:loaded_node_provider = 1
-let g:provider#node#enabled = 0
+let g:loaded_node_provider = 0
 
 function! s:is_minimum_version(version, min_major, min_minor) abort
   if empty(a:version)
@@ -141,12 +140,10 @@ endfunction
 
 let s:err = ''
 let s:prog = provider#node#Detect()
+let g:loaded_node_provider = !empty(s:prog)
 
-if empty(s:prog)
+if !g:loaded_node_provider
   let s:err = 'Cannot find the "neovim" node package. Try :checkhealth'
-else
-  let g:provider#node#enabled = 1
 endif
 
 call remote#host#RegisterPlugin('node-provider', 'node', [])
-
diff --git a/runtime/autoload/provider/python.vim b/runtime/autoload/provider/python.vim
index d65506a55a..7921701141 100644
--- a/runtime/autoload/provider/python.vim
+++ b/runtime/autoload/provider/python.vim
@@ -7,10 +7,8 @@
 if exists('g:loaded_python_provider')
   finish
 endif
-let g:loaded_python_provider = 1
-
 let [s:prog, s:err] = provider#pythonx#Detect(2)
-let g:provider#python#enabled = !empty(s:prog)
+let g:loaded_python_provider = !empty(s:prog)
 
 function! provider#python#Prog() abort
   return s:prog
diff --git a/runtime/autoload/provider/python3.vim b/runtime/autoload/provider/python3.vim
index 469611c7ce..67350e3753 100644
--- a/runtime/autoload/provider/python3.vim
+++ b/runtime/autoload/provider/python3.vim
@@ -7,10 +7,8 @@
 if exists('g:loaded_python3_provider')
   finish
 endif
-let g:loaded_python3_provider = 1
-
 let [s:prog, s:err] = provider#pythonx#Detect(3)
-let g:provider#python3#enabled = !empty(s:prog)
+let g:loaded_python3_provider = !empty(s:prog)
 
 function! provider#python3#Prog() abort
   return s:prog
diff --git a/runtime/autoload/provider/ruby.vim b/runtime/autoload/provider/ruby.vim
index df43dffa40..f9d4f2b885 100644
--- a/runtime/autoload/provider/ruby.vim
+++ b/runtime/autoload/provider/ruby.vim
@@ -2,12 +2,11 @@
 if exists('g:loaded_ruby_provider')
   finish
 endif
-let g:loaded_ruby_provider = 1
+let g:loaded_ruby_provider = 0
 
 function! provider#ruby#Detect() abort
   return s:prog
 endfunction
-let g:provider#ruby#enabled = 0
 
 function! provider#ruby#Prog() abort
   return s:prog
@@ -63,11 +62,10 @@ endfunction
 let s:err = ''
 let s:prog = s:detect()
 let s:plugin_path = expand('<sfile>:p:h') . '/script_host.rb'
+let g:loaded_ruby_provider = !empty(s:prog)
 
-if empty(s:prog)
+if !g:loaded_ruby_provider
   let s:err = 'Cannot find the neovim RubyGem. Try :checkhealth'
-else
-  let g:provider#ruby#enabled = 1
 endif
 
 call remote#host#RegisterClone('legacy-ruby-provider', 'ruby')
diff --git a/runtime/doc/develop.txt b/runtime/doc/develop.txt
index 0f9e17e697..180612cf20 100644
--- a/runtime/doc/develop.txt
+++ b/runtime/doc/develop.txt
@@ -84,12 +84,11 @@ Developer guidelines				        *dev-guidelines*
 
 PROVIDERS 						*dev-provider*
 
-A goal of Nvim is to allow extension of the editor without special knowledge
-in the core. But some Vim components are too tightly coupled; in those cases
-a "provider" hook is exposed.
+A primary goal of Nvim is to allow extension of the editor without special
+knowledge in the core.  Some core functions are delegated to "providers"
+implemented as external scripts.
 
-Consider two examples of integration with external systems that are
-implemented in Vim and are now decoupled from Nvim core as providers:
+Examples:
 
 1. In the Vim source code, clipboard logic accounts for more than 1k lines of
    C source code (ui.c), to perform two tasks that are now accomplished with
@@ -101,29 +100,28 @@ implemented in Vim and are now decoupled from Nvim core as providers:
    scripting is performed by an external host process implemented in ~2k lines
    of Python.
 
-Ideally we could implement Python and clipboard integration in pure vimscript
-and without touching the C code. But this is infeasible without compromising
-backwards compatibility with Vim; that's where providers help.
+The provider framework invokes VimL from C.  It is composed of two functions
+in eval.c:
 
-The provider framework helps call vimscript from C. It is composed of two
-functions in eval.c:
-
-- eval_call_provider(name, method, arguments): calls provider#(name)#Call
+- eval_call_provider(name, method, arguments): calls provider#{name}#Call
   with the method and arguments.
-- eval_has_provider(name): Checks if a provider is implemented. Returns true
-  if the provider#(name)#enabled variable is not 0. Called by |has()|
-  (vimscript) to check if features are available.
-
-The provider#(name)#Call function implements integration with an external
-system, because shell commands and |RPC| clients are easier to work with in
-vimscript.
+- eval_has_provider(name): Checks the `g:loaded_{name}_provider` variable
+  which must be set by the provider script to indicate whether it is enabled
+  and working. Called by |has()| to check if features are available.
 
 For example, the Python provider is implemented by the
-autoload/provider/python.vim script; the variable provider#python#enabled is only
-1 if a valid external Python host is found. That works well with the
-`has('python')` expression (normally used by Python plugins) because if the
-Python host isn't installed then the plugin will "think" it is running in
-a Vim compiled without the "+python" feature.
+"autoload/provider/python.vim" script, which sets `g:loaded_python_provider`
+to TRUE only if a valid external Python host is found.  Then `has("python")`
+reflects whether Python support is working.
+
+							*provider-reload*
+Sometimes a GUI or other application may want to force a provider to
+"reload".  To reload a provider, undefine its "loaded" flag, then use
+|:runtime| to reload it: >
+
+    :unlet g:loaded_clipboard_provider
+    :runtime autoload/provider/clipboard.vim
+
 
 DOCUMENTATION						*dev-doc*