add a cool lua repl

1 files changed, 192 insertions, 0 deletions

diff --git a/lib/lua-repl/repl/plugins/completion.lua b/lib/lua-repl/repl/plugins/completion.lua
new file mode 100644
index 00000000..938c7439
--- /dev/null
+++ b/lib/lua-repl/repl/plugins/completion.lua
@@ -0,0 +1,192 @@
+-- Copyright (c) 2011-2015 Rob Hoelz <rob@hoelz.ro>
+--
+-- Permission is hereby granted, free of charge, to any person obtaining a copy of
+-- this software and associated documentation files (the "Software"), to deal in
+-- the Software without restriction, including without limitation the rights to
+-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+-- the Software, and to permit persons to whom the Software is furnished to do so,
+-- subject to the following conditions:
+--
+-- The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+-- FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+-- COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+-- IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+-- CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+local utils        = require 'repl.utils'
+local getmetatable = getmetatable
+local pairs        = pairs
+local sfind        = string.find
+local sgmatch      = string.gmatch
+local smatch       = string.match
+local ssub         = string.sub
+local tconcat      = table.concat
+local tsort        = table.sort
+local type         = type
+
+local function isindexable(value)
+  if type(value) == 'table' then
+    return true
+  end
+
+  local mt = getmetatable(value)
+
+  return mt and mt.__index
+end
+
+local function getcompletions(t)
+  local union = {}
+
+  while isindexable(t) do
+    if type(t) == 'table' then
+      -- XXX what about the pairs metamethod in 5.2?
+      --     either we don't care, we implement a __pairs-friendly
+      --     pairs for 5.1, or implement a 'rawpairs' for 5.2
+      for k, v in pairs(t) do
+        if union[k] == nil then
+          union[k] = v
+        end
+      end
+    end
+
+    local mt = getmetatable(t)
+    t        = mt and mt.__index or nil
+  end
+
+  return pairs(union)
+end
+
+local function split_ns(expr)
+  if expr == '' then
+    return { '' }
+  end
+
+  local pieces = {}
+
+  -- XXX method calls too (option?)
+  for m in sgmatch(expr, '[^.]+') do
+    pieces[#pieces + 1] = m
+  end
+
+  -- logic for determining whether to pad the matches with the empty
+  -- string (ugly)
+  if ssub(expr, -1) == '.' then
+    pieces[#pieces + 1] = ''
+  end
+
+  return pieces
+end
+
+local function determine_ns(expr)
+  local ns     = _G -- XXX what if the REPL lives in a special context? (option?)
+  local pieces = split_ns(expr)
+
+  for index = 1, #pieces - 1 do
+    local key = pieces[index]
+    -- XXX rawget? or regular access? (option?)
+    ns = ns[key]
+
+    if not isindexable(ns) then
+      return {}, '', ''
+    end
+  end
+
+  expr = pieces[#pieces]
+
+  local prefix = ''
+
+  if #pieces > 1 then
+    prefix = tconcat(pieces, '.', 1, #pieces - 1) .. '.'
+  end
+
+  local last_piece = pieces[#pieces]
+
+  local before, after = smatch(last_piece, '(.*):(.*)')
+
+  if before then
+    ns     = ns[before] -- XXX rawget
+    prefix = prefix .. before .. ':'
+    expr   = after
+  end
+
+  return ns, prefix, expr
+end
+
+local isidentifierchar
+
+do
+  local ident_chars_set = {}
+  -- XXX I think this can be done with isalpha in C...
+  local ident_chars     = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.:_0123456789'
+
+  for i = 1, #ident_chars do
+    local char = ssub(ident_chars, i, i)
+    ident_chars_set[char] = true
+  end
+
+  function isidentifierchar(char)
+    return ident_chars_set[char]
+  end
+end
+
+local function extract_innermost_expr(expr)
+  local index = #expr
+
+  while index > 0 do
+    local char = ssub(expr, index, index)
+    if isidentifierchar(char) then
+      index = index - 1
+    else
+      break
+    end
+  end
+
+  index = index + 1
+
+  return ssub(expr, 1, index - 1), ssub(expr, index)
+end
+
+-- XXX is this logic (namely, returning the entire line) too specific to
+--     linenoise?
+function repl:complete(expr, callback)
+  if utils.ends_in_unfinished_string(expr) then
+    return
+  end
+
+  local ns, prefix, path
+
+  prefix, expr = extract_innermost_expr(expr)
+
+  ns, path, expr = determine_ns(expr)
+
+  prefix = prefix .. path
+
+  local completions = {}
+
+  for k, v in getcompletions(ns) do
+    if sfind(k, expr, 1, true) == 1 then
+      local suffix = ''
+      local type   = type(v)
+
+      -- XXX this should be optional
+      if type == 'function' then
+        suffix = '('
+      elseif type == 'table' then
+        suffix = '.'
+      end
+
+      completions[#completions + 1] = prefix .. k .. suffix
+    end
+  end
+
+  tsort(completions)
+
+  for _, completion in ipairs(completions) do
+    callback(completion)
+  end
+end
+
+features = 'completion'