From e5cb62708736820c09432d02710835b23989c407 Mon Sep 17 00:00:00 2001
From: Evie Litherland-Smith <evie.litherland-smith@ukaea.uk>
Date: Wed, 2 Nov 2022 11:14:31 +0000
Subject: [PATCH] Use pyright (if available), fallback to pylsp otherwise

---
 README.md          |  2 +-
 lua/config_lsp.lua | 52 +++++++++++++++++++++++++++++++---------------
 2 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/README.md b/README.md
index 57ca31e1..a27606cf 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ Plugin definitions are in `plugins.lua`, inside `vim` run `:PackerSync` to insta
 pyenv virtualenv neovim3  # Assumes working pyenv
 pyenv activate neovim3
 pip install -U pip setuptools wheel
-pip install -U pynvim "python-lsp-server[all]" fortls pylsp-mypy python-lsp-black
+pip install -U pynvim pyright fortl  # If pyright not available, fallback to: "python-lsp-server[all]" pylsp-mypy
 pyenv deactivate
 ```
 
diff --git a/lua/config_lsp.lua b/lua/config_lsp.lua
index 4996c588..e2a45160 100644
--- a/lua/config_lsp.lua
+++ b/lua/config_lsp.lua
@@ -104,25 +104,43 @@ cmp.setup.cmdline(':', {
 -- Setup lspconfig.
 local capabilities = require('cmp_nvim_lsp').default_capabilities(vim.lsp.protocol.make_client_capabilities())
 
-require('lspconfig')['pylsp'].setup{
-    cmd = {os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/pylsp"},
-    on_attach = on_attach,
-    flags = lsp_flags,
-    settings = {
-        pylsp = {
-            plugins = {
-                pycodestyle = {maxLineLength = 88},
-                flake8 = {maxLineLength = 88}
-            }
+local function file_exists(name)
+       local f=io.open(name,"r")
+       if f~=nil then io.close(f) return true else return false end
+end
+
+local pyright_file = os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/pyright-langserver"
+local pylsp_file = os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/pylsp"
+
+if file_exists(pyright_file) then
+        require('lspconfig')['pyright'].setup{
+                cmd = {pyright_file, "--stdio"},
+                on_attach = on_attach,
+                flags = lsp_flags,
+                capabilities = capabilities,
         }
-    },
-    capabilities = capabilities
-}
+elseif file_exists(pylsp_file) then
+        require('lspconfig')['pylsp'].setup{
+            cmd = {pylsp_file},
+            on_attach = on_attach,
+            flags = lsp_flags,
+            settings = {
+                pylsp = {
+                    plugins = {
+                        pycodestyle = {maxLineLength = 88},
+                        flake8 = {maxLineLength = 88}
+                    }
+                }
+            },
+            capabilities = capabilities
+        }
+end
+
 require('lspconfig')['fortls'].setup{
-    cmd = {os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/fortls"},
-    on_attach = on_attach,
-    flags = lsp_flags,
-    capabilities = capabilities
+        cmd = {os.getenv( "HOME" ).."/.pyenv/versions/neovim3/bin/fortls"},
+        on_attach = on_attach,
+        flags = lsp_flags,
+        capabilities = capabilities
 }
 
 require('lspconfig')['sumneko_lua'].setup {