feat: nvim: treesitter: enable code folding

nix/base-system/flake.lock

@@ -1818,11 +1818,11 @@
     },
     "unstable": {
       "locked": {
-        "lastModified": 1746152631,
-        "narHash": "sha256-zBuvmL6+CUsk2J8GINpyy8Hs1Zp4PP6iBWSmZ4SCQ/s=",
+        "lastModified": 1747312588,
+        "narHash": "sha256-MmJvj6mlWzeRwKGLcwmZpKaOPZ5nJb/6al5CXqJsgjo=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "032bc6539bd5f14e9d0c51bd79cfe9a055b094c3",
+        "rev": "b1bebd0fe266bbd1820019612ead889e96a8fa2d",
         "type": "github"
       },
       "original": {

nix/base-system/flake.nix

@@ -292,6 +292,7 @@ EOF";
             uv = unstablePkgs.uv;
             quint = (pkgs.callPackage ../packages/quint/default.nix {})."@informalsystems/quint";
             quint-lsp = (pkgs.callPackage ../packages/quint/default.nix {})."@informalsystems/quint-language-server";
+            ollama = unstablePkgs.ollama;
           })
           rust-overlay
         ];

nix/base-system/init.lua

@@ -43,6 +43,23 @@ vim.api.nvim_create_autocmd({ "BufEnter", "BufWinEnter" }, {
     end,
 })
 
+vim.api.nvim_create_autocmd({ "BufNewfile", "BufRead" }, {
+    callback = function(args)
+        -- If treesitter supports this filetype then use the treesitter fold expression
+        local ft = vim.bo.filetype
+        if ft and ft ~= "" then
+            -- Safely check if a parser exists for this filetype
+            local has_parser = pcall(function() return vim.treesitter.language.inspect(ft) end)
+            if has_parser then
+                vim.wo.foldexpr = 'v:lua.vim.treesitter.foldexpr()'
+                vim.wo.foldmethod = 'expr'
+                vim.wo.foldlevel = 3
+            end
+        end
+    end,
+})
+
+
 vim.cmd([[
 au BufNewFile,BufRead *Makefile,*.mk set noexpandtab
 ]])
@@ -320,31 +337,16 @@ require('nvim-treesitter.configs').setup {
         extended_mode = true,
         max_file_lines = nil,
     },
-    --textobjects = {
-    --  enable = true,
-    --  select = {
-    --    enable = true,
-    --    lookahead = true, -- Automatically jump forward to textobj, similar to targets.vim
-    --    keymaps = {
-    --      -- You can use the capture groups defined in textobjects.scm
-    --      ['aa'] = '@parameter.outer',
-    --      ['ia'] = '@parameter.inner',
-    --      ['af'] = '@function.outer',
-    --      ['if'] = '@function.inner',
-    --      ['ac'] = '@class.outer',
-    --      ['ic'] = '@class.inner',
-    --    },
-    --  },
-    --},
-    --incremental_selection = {
-    --  enable = true,
-    --  keymaps = {
-    --    init_selection = '<Leader>c',
-    --    node_incremental = '<Leader>c',
-    --    scope_incremental = '<Leader>ci',
-    --    node_decremental = '<Leader>cx',
-    --  },
-    --},
+    textobjects = { enable = true },
+    incremental_selection = {
+      enable = true,
+      keymaps = {
+        init_selection = '<Leader>c',
+        node_incremental = '<Leader>c',
+        scope_incremental = '<Leader>ci',
+        node_decremental = '<Leader>cx',
+      },
+    },
 }
 
 require 'treesitter-context'.setup {