fix(snippets): make read_file() work with function array items

echasnovski · echasnovski · commit 126ce3328c78 · 2025-09-30T12:46:10.000+03:00
Resolve #2032
diff --git a/doc/mini-snippets.txt b/doc/mini-snippets.txt
@@ -349,6 +349,9 @@ General advice:
   example from |MiniSnippets-examples|.
 - Prefer `*.json` files with dict-like content if you want more cross platfrom
   setup. Otherwise use `*.lua` files with array-like content.
+- To implement "dynamic snippet" that changes data (usually <body>) depending
+  on the context, use `*.lua` file with function returning snippet data.
+  It should be an element in the output table (dict or array like).
 
 Notes:
 - There is no built-in support for VSCode-like "package.json" files. Define
diff --git a/lua/mini/snippets.lua b/lua/mini/snippets.lua
@@ -346,6 +346,9 @@
 ---   example from |MiniSnippets-examples|.
 --- - Prefer `*.json` files with dict-like content if you want more cross platfrom
 ---   setup. Otherwise use `*.lua` files with array-like content.
+--- - To implement "dynamic snippet" that changes data (usually <body>) depending
+---   on the context, use `*.lua` file with function returning snippet data.
+---   It should be an element in the output table (dict or array like).
 ---
 --- Notes:
 --- - There is no built-in support for VSCode-like "package.json" files. Define
@@ -376,7 +379,6 @@
 --- - Set up 'mini.snippets' as recommended in |MiniSnippets-examples|.
 --- - Open Neovim. Type each snippet prefix and press <C-j> (even if there is
 ---   still active session). Explore from there.
----
 ---@tag MiniSnippets-overview
 
 --- # Basic snippet management config ~
@@ -1657,7 +1659,7 @@ H.file_readers.lua = function(path, silent)
   local ok, contents = pcall(dofile, path)
   if not ok then return { problems = { 'Could not execute Lua file' } } end
   if type(contents) ~= 'table' then return { problems = { 'Returned object is not a table' } } end
-  return H.read_snippet_dict(contents)
+  return H.read_snippet_data(contents)
 end
 
 H.file_readers.json = function(path, silent)
@@ -1672,18 +1674,21 @@ H.file_readers.json = function(path, silent)
     return { problems = { 'File does not contain a valid JSON object. Reason: ' .. msg } }
   end
 
-  return H.read_snippet_dict(contents)
+  return H.read_snippet_data(contents)
 end
 
 H.file_readers['code-snippets'] = H.file_readers.json
 
-H.read_snippet_dict = function(contents)
+H.read_snippet_data = function(contents)
   local res, problems = {}, {}
   for name, t in pairs(contents) do
     if H.is_snippet(t) then
       -- Try inferring description from dict's field (if appropriate)
       if type(name) == 'string' and (t.desc == nil and t.description == nil) then t.desc = name end
       table.insert(res, t)
+    elseif vim.is_callable(t) then
+      -- Allow entries to be functions (relevant for Lua files)
+      table.insert(res, t)
     else
       table.insert(problems, 'The following is not a valid snippet data:\n' .. vim.inspect(t))
     end
diff --git a/tests/dir-snippets/file-dynamic-snippets.lua b/tests/dir-snippets/file-dynamic-snippets.lua
@@ -0,0 +1,9 @@
+return {
+  function(context) return { prefix = 'dyn', body = 'Buf: ' .. context.buf_id, desc = 'Dynamic' } end,
+  -- Should also work with function returning (maybe nested) function
+  function(_)
+    return {
+      function(con) return { prefix = 'dynest', body = 'Buf (from nested): ' .. con.buf_id, desc = 'Dynamic nested' } end,
+    }
+  end,
+}
diff --git a/tests/test_snippets.lua b/tests/test_snippets.lua
@@ -883,6 +883,19 @@ T['gen_loader']['from_file()']['works'] = function()
   eq(child.lua_get('_G.loader_tilde()'), out)
 end
 
+T['gen_loader']['from_file()']['works with function items'] = function()
+  child.lua('_G.file_dynamic_path = ' .. vim.inspect(test_dir_absolute .. '/file-dynamic-snippets.lua'))
+  local dyn_snippets = child.lua([[
+    MiniSnippets.config.snippets = { MiniSnippets.gen_loader.from_file(_G.file_dynamic_path) }
+    return MiniSnippets.expand({ match = false, insert = false })
+  ]])
+  local buf_id = get_buf()
+  eq(dyn_snippets, {
+    { prefix = 'dyn', body = 'Buf: ' .. buf_id, desc = 'Dynamic' },
+    { prefix = 'dynest', body = 'Buf (from nested): ' .. buf_id, desc = 'Dynamic nested' },
+  })
+end
+
 T['gen_loader']['from_file()']['does not cache if there were reading problems'] = function()
   local temp_file = child.lua([[
     local temp_file = vim.fn.tempname() .. '.lua'
@@ -991,6 +1004,21 @@ T['read_file()']['works with array-like content'] = function()
   validate('file-array.code-snippets')
 end
 
+T['read_file()']['works with function items'] = function()
+  child.lua('_G.file_dynamic_path = ' .. vim.inspect(test_dir_absolute .. '/file-dynamic-snippets.lua'))
+  local dyn_snippets = child.lua([[
+    MiniSnippets.config.snippets = {
+      function() return MiniSnippets.read_file(_G.file_dynamic_path) end
+    }
+    return MiniSnippets.expand({ match = false, insert = false })
+  ]])
+  local buf_id = get_buf()
+  eq(dyn_snippets, {
+    { prefix = 'dyn', body = 'Buf: ' .. buf_id, desc = 'Dynamic' },
+    { prefix = 'dynest', body = 'Buf (from nested): ' .. buf_id, desc = 'Dynamic nested' },
+  })
+end
+
 T['read_file()']['works with relative paths'] = function()
   child.fn.chdir(test_dir_absolute)
   eq(read_file('snippets/lua.json'), { { prefix = 'a', body = 'A=$1', desc = 'snippets/lua.json' } })
