Add option to suggest words in different cases

lua/cmp_buffer/cases.lua

@@ -0,0 +1,120 @@
+-- slice a word to individual slices. "my_cool_word" -> { "my", "cool", "word" }
+function get_word_slices(name)
+  local slices = {}
+  local current_word = ""
+  local last_character_uppercase = true
+
+  for i = 1, #name do
+    local character = name:sub(i, i)
+
+    if character == "_" or character == "-" then
+      if current_word ~= "" then
+        table.insert(slices, current_word)
+        current_word = ""
+      end
+
+      last_character_uppercase = false
+    elseif string.upper(character) == character then
+
+      if last_character_uppercase or current_word == "" then
+        current_word = current_word .. string.lower(character)
+      else
+        table.insert(slices, current_word)
+        current_word = string.lower(character)
+      end
+
+      last_character_uppercase = true
+    else
+      current_word = current_word .. character
+      last_character_uppercase = false
+    end
+  end
+
+  if current_word ~= "" then
+    table.insert(slices, current_word)
+  end
+
+  return slices
+end
+
+-- e.g. my_cool_word
+function snake_case(slices)
+  local word = ""
+
+  for index, slice in ipairs(slices) do
+    if index > 1 then
+      word = word .. "_"
+    end
+
+    word = word .. slice
+  end
+
+  return word
+end
+
+-- e.g. my-cool-word
+function kebab_case(slices)
+  local word = ""
+
+  for index, slice in ipairs(slices) do
+    if index > 1 then
+      word = word .. "-"
+    end
+
+    word = word .. slice
+  end
+
+  return word
+end
+
+-- e.g. myCoolWord
+function camel_case(slices)
+  local word = ""
+
+  for index, slice in ipairs(slices) do
+    if index == 1 then
+      word = word .. slice
+    else
+      word = word .. string.upper(string.sub(slice, 1, 1))
+      word = word .. string.sub(slice, 2, -1)
+    end
+  end
+
+  return word
+end
+
+-- e.g. MyCoolWord
+function pascal_case(slices)
+  local word = ""
+
+  for _, slice in ipairs(slices) do
+    word = word .. string.upper(string.sub(slice, 1, 1))
+    word = word .. string.sub(slice, 2, -1)
+  end
+
+  return word
+end
+
+-- e.g. MY_COOL_WORD
+function macro_case(slices)
+  local word = ""
+
+  for index, slice in ipairs(slices) do
+    if index > 1 then
+      word = word .. "_"
+    end
+
+    word = word .. string.upper(slice)
+  end
+
+  return word
+end
+
+-- lookup table for all cases that are suppored out of the box
+return {
+  ["snake"] = snake_case,
+  ["camel"] = camel_case,
+  ["pascal"] = pascal_case,
+  ["kebab"] = kebab_case,
+  ["macro"] = macro_case,
+}

lua/cmp_buffer/source.lua

@@ -1,4 +1,5 @@
 local buffer = require('cmp_buffer.buffer')
+local case_lookup = require('cmp_buffer.cases')
 
 ---@class cmp_buffer.Options
 ---@field public keyword_length number
@@ -7,6 +8,7 @@ local buffer = require('cmp_buffer.buffer')
 ---@field public indexing_batch_size number
 ---@field public indexing_interval number
 ---@field public max_indexed_line_length number
+---@field public cases table
 
 ---@type cmp_buffer.Options
 local defaults = {
@@ -18,6 +20,7 @@ local defaults = {
   indexing_batch_size = 1000,
   indexing_interval = 100,
   max_indexed_line_length = 1024 * 40,
+  cases = {},
 }
 
 local source = {}
@@ -37,6 +40,7 @@ source._validate_options = function(_, params)
     get_bufnrs = { opts.get_bufnrs, 'function' },
     indexing_batch_size = { opts.indexing_batch_size, 'number' },
     indexing_interval = { opts.indexing_interval, 'number' },
+    cases = { opts.cases, 'table' },
   })
   return opts
 end
@@ -71,6 +75,33 @@ source.complete = function(self, params, callback)
               label = word,
               dup = 0,
             })
+
+            if opts.cases ~= {} then
+              local slices = get_word_slices(word)
+
+              for _, case in ipairs(opts.cases) do
+                local new_word
+
+                if type(case) == "function" then
+                  new_word = case(slices)
+                else
+                  local converter = case_lookup[case]
+                  if converter ~= nil then
+                    new_word = converter(slices)
+                  end
+                end
+
+                if type(new_word) == "string" then
+                  if not words[new_word] then
+                    words[new_word] = true
+                    table.insert(items, {
+                      label = new_word,
+                      dup = 0,
+                    })
+                  end
+                end
+              end
+            end
           end
         end
       end