Initial clod library

1 files changed, 127 insertions, 0 deletions

diff --git a/lib/clod.lua b/lib/clod.lua
new file mode 100644
index 0000000..d25048b
--- /dev/null
+++ b/lib/clod.lua
@@ -0,0 +1,127 @@
+-- lib/clod.lua
+--
+-- Configuration Language Organised (by) Dots
+--
+-- Copyright 2012 Daniel Silverstone <dsilvers@digital-scurf.org>
+--
+
+local type = type
+local getinfo = debug.getinfo
+local pcall = pcall
+local loadstring = loadstring
+local tconcat = table.concat
+local setmetatable = setmetatable
+local setfenv = setfenv
+
+-- metatable for clod config operations
+local clod_mt = {}
+-- metadata for clod config instances
+local metadata = setmetatable({}, {__mode = "k"})
+
+-- Methods for clod instances
+local methods = {}
+
+function methods:serialise()
+   local entries = metadata[self].entries
+   local retstr = {}
+   local function serialise_entry(entry)
+      local key, value, line = entry.key, entry.value, ""
+      if entry.key then
+	 local vtype = type(value)
+	 if vtype == "string" then
+	    line = ("%s %q"):format(key, value)
+	 elseif vtype == "number" then
+	    line = ("%s = %d"):format(key, value)
+	 elseif vtype == "boolean" then
+	    line = ("%s = %s"):format(key, value and "true" or "false")
+	 else
+	    line = ("-- %s was a %s.  Cannot serialise"):format(key, vtype)
+	 end
+      end
+      retstr[#retstr+1] = line
+   end
+   while entries do
+      serialise_entry(entries)
+      entries = entries.next
+   end
+   serialise_entry({})
+   return tconcat(retstr, "\n")
+end
+
+-- Metamethods for clod instances
+function clod_mt:__index(key)
+   if key == "settings" then
+      return gen_settings(self)
+   elseif methods[key] then
+      return methods[key]
+   end
+end
+
+local function parse_config(conf, confname)
+   local ret = {}
+   local settings = {}
+   local last_entry = {lineno = 0}
+   local front_entry = last_entry
+   local keys = {}
+   local parse_mt = {}
+   local function gen_hook(key)
+      local ret = setmetatable({}, parse_mt)
+      keys[ret] = key
+      return ret
+   end
+   function parse_mt:__index(key)
+      local prefix = keys[self]
+      if not prefix then
+	 -- This is a global indexing, so return a fresh entry
+	 return gen_hook(key)
+      end
+      -- A 'local' indexing, so combine with the key
+      return gen_hook(("%s.%s"):format(prefix, key))
+   end
+   function parse_mt:__setindex(key, value)
+      -- This is the equivalent of 'foo = "bar"' instead of 'foo "bar"'
+      return self[key](value)
+   end
+   function parse_mt:__call(value)
+      local key = assert(keys[self])
+      local curline = getinfo(2, "Snlf").currentline
+      local entry = { key = key, value = value, lineno = curline }
+      while last_entry.lineno < (curline - 1) do
+	 local empty = { 
+	    lineno = last_entry.lineno + 1,
+	    prev = last_entry
+	 }
+	 last_entry.next = empty
+	 last_entry = empty
+      end
+      last_entry.next = entry
+      entry.prev = last_entry
+      last_entry = entry
+      settings[key] = entry
+   end
+   local func, msg = loadstring(conf, ("@%s"):format(confname or "clod-config"))
+   if not func then
+      return nil, msg
+   end
+   local globs = setmetatable({}, parse_mt)
+   setfenv(func, globs)
+   local ok, err = pcall(func)
+   if not ok then
+      return nil, err
+   end
+   -- Successfully loaded the settings, they're in settings and front_entry
+   -- points to line zero which we can now detach
+   front_entry.next.prev = nil
+   front_entry = front_entry.next
+   -- Construct a return object ready for magic
+   local ret = setmetatable({}, clod_mt)
+   metadata[ret] = {
+      settings = settings,
+      entries = front_entry,
+   }
+   return ret
+end
+
+return {
+   parse = parse_config,
+}