2 files changed, 33 insertions, 10 deletions
diff --git a/lua/simple-denote/api.lua b/lua/simple-denote/api.lua
index c26bafd..a03c9f2 100644
--- a/lua/simple-denote/api.lua
+++ b/lua/simple-denote/api.lua
@@ -4,7 +4,7 @@ local internal = require("simple-denote.internal")
 
 ---@param options table
 ---@param title string|nil
----@param keywords table|nil
+---@param keywords string|nil
 function M.note(options, title, keywords)
   if not title then
     vim.ui.input({ prompt = "Note title: " }, function(input)
@@ -38,7 +38,7 @@ end
 
 ---@param options table
 ---@param filename string|nil
----@param keywords table|nil
+---@param keywords string|nil
 function M.keywords(options, filename, keywords)
   if not filename then
     filename = vim.fn.expand("%")
@@ -52,10 +52,9 @@ function M.keywords(options, filename, keywords)
   internal.keyword(options, filename, keywords)
 end
 
----@param options table
 ---@param filename string|nil
----@param sig string
-function M.signature(options, filename, sig)
+---@param sig string|nil
+function M.signature(filename, sig)
   filename = filename or vim.fn.expand("%")
   if not sig then
     vim.ui.input({ prompt = "Signature: " }, function(input)
@@ -63,7 +62,21 @@ function M.signature(options, filename, sig)
     end)
   end
   if not sig then return end
-  internal.signature(options, filename, sig)
+  internal.signature(filename, sig)
+end
+
+---@param filename string|nil
+---@param ext string|nil
+function M.extension(filename, ext)
+  filename = filename or vim.fn.expand("%")
+  if not ext then
+    vim.ui.input({ prompt = "Extension: " }, function(input)
+      ext = input
+    end)
+  end
+  if not ext then return end
+  internal.extension(filename, ext)
 end
 
+
 return M
diff --git a/lua/simple-denote/internal.lua b/lua/simple-denote/internal.lua
index 73ba71f..8821689 100644
--- a/lua/simple-denote/internal.lua
+++ b/lua/simple-denote/internal.lua
@@ -18,7 +18,7 @@ function M.plain_format(str)
 end
 
 ---@param str string
----@param char delimiter that replaces spaces (- for titles, _ for keywords, = for sigs)
+---@param char string delimiter that replaces spaces (- for titles, _ for keywords, = for sigs)
 ---Format the title/keywords/sig string of a Denote filename
 function M.format_denote_string(str, char)
   str = M.plain_format(str)
@@ -28,7 +28,6 @@ function M.format_denote_string(str, char)
 end
 
 ---@param title string heading text
----@param ext string file extension
 ---Set the first line to title if it's an empty buffer or the first line is a heading
 function M.set_heading(options, title)
   if title == "" then return end
@@ -108,11 +107,10 @@ function M.keyword(options, filename, keywords)
   M.replace_file(filename, new_filename)
 end
 
----@param options table
 ---@param filename string
 ---@param sig string
 ---Add/change the ==signature in the filename
-function M.signature(options, filename, sig)
+function M.signature(filename, sig)
   local prefix, suffix = filename:match("^(.-%d%d%d%d%d%d%d%dT%d%d%d%d%d%d)(.*)")
   if not prefix then
     error("This doesn't look like a Denote filename")
@@ -123,4 +121,16 @@ function M.signature(options, filename, sig)
   M.replace_file(filename, new_filename)
 end
 
+---@param filename string
+---@param ext string
+---Replace the extension in the file with ext
+function M.extension(filename, ext)
+  local prefix, _ = filename:match("^(.-%d%d%d%d%d%d%d%dT%d%d%d%d%d%d.*%.)(.+)$")
+  if not prefix then
+    error("This doesn't look like a Denote file")
+  end
+  local new_filename = prefix .. ext
+  M.replace_file(filename, new_filename)
+end
+
 return M