feat: Added some docs & validation

README.md

@@ -372,6 +372,30 @@ Themes should work with every `telescope.builtin` function.
 
 If you wish to make theme, check out `lua/telescope/themes.lua`. If you need more features, make an issue :).
 
+## Configuration
+
+### Display
+
+`Resolvable`:
+1. 0 <= number < 1:
+    - This means total height as a percentage
+2. 1 <= number:
+    - This means total height as a fixed number
+3. function(picker, columns, lines):
+    - returns one of the above options
+    - `return max.min(110, max_rows * .5)`
+
+```lua
+layout_strategies.horizontal = function(self, max_columns, max_lines)
+  local layout_config = validate_layout_config(self.layout_config or {}, {
+    width_padding = "How many cells to pad the width",
+    height_padding = "How many cells to pad the height",
+    preview_width = "(Resolvable): Determine preview width",
+  })
+  ...
+end
+```
+
 ## Goals
 
 ### Pipeline Different Objects

lua/telescope/config/resolve.lua

@@ -32,19 +32,13 @@ Result of `resolve` should be a table with:
 !!NOT IMPLEMENTED YET!!
 
 height =
-    1. pass between 0 & 1
+    1. 0 <= number < 1
         This means total height as a percentage
 
-    2. pass a number > 1
+    2. 1 <= number
         This means total height as a fixed number
 
-    3. {
+    3. function(picker, columns, lines)
-        previewer = x,
-        results = x,
-        prompt = x,
-    }, this means I do my best guess I can for these, given your options
-
-    4. function(max_rows)
         -> returns one of the above options
         return max.min(110, max_rows * .5)
 
@@ -54,6 +48,12 @@ height =
             return 0.6
         end
 
+    3. {
+        previewer = x,
+        results = x,
+        prompt = x,
+    }, this means I do my best guess I can for these, given your options
+
 width =
     exactly the same, but switch to width
 

lua/telescope/pickers/layout_strategies.lua

@@ -33,6 +33,21 @@ local is_borderless = function(opts)
   return opts.window.border == false
 end
 
+
+local function validate_layout_config(options, values)
+  for k, _ in pairs(options) do
+    if not values[k] then
+      error(string.format(
+        "Unsupported layout_config key: %s\n%s",
+        k,
+        vim.inspect(values)
+      ))
+    end
+  end
+
+  return options
+end
+
 local layout_strategies = {}
 
 --[[
@@ -46,7 +61,11 @@ local layout_strategies = {}
    +-----------------+---------------------+
 --]]
 layout_strategies.horizontal = function(self, max_columns, max_lines)
-  local layout_config = self.layout_config or {}
+  local layout_config = validate_layout_config(self.layout_config or {}, {
+    width_padding = "How many cells to pad the width",
+    height_padding = "How many cells to pad the height",
+    preview_width = "(Resolvable): Determine preview width",
+  })
 
   local initial_options = self:_get_initial_window_options()
   local preview = initial_options.preview