Implemented dumb database for standard C headers

1 files changed, 130 insertions, 0 deletions

diff --git a/headers.lua b/headers.lua
new file mode 100755
index 0000000..13d98a9
--- /dev/null
+++ b/headers.lua
@@ -0,0 +1,130 @@
+#!/usr/bin/env lua
+--- For example:
+---
+---     $ ./headers.lua db/c.lua C23
+---     assert.h
+---     ctype.h
+---     ...
+local public = {}
+local private = {}
+private.tags = {}
+private.tags_lookup = {}
+private.headers = {}
+
+
+local tag do
+	local methods = {}
+	function methods:add (header)
+		table.insert(self.headers_, header)
+	end
+	local function headers (self)
+		local result = {}
+		for _, value in pairs(self.headers_) do
+			if type(value) == "function" then
+				value(result)
+			else
+				table.insert(result, value)
+			end
+		end
+		return result
+	end
+	local mt = {
+		__tostring=function (self) return self.name end,
+		__index=function (self, key)
+			if key == "headers" then
+				return headers(self)
+			end
+			return methods[key]
+		end,
+	}
+	function tag (name)
+		return setmetatable({name=name, headers_={}}, mt)
+	end
+end
+
+
+local alias do
+	local mt = {
+		__tostring = function (self) return string.format("%s (%s)", self.name, tostring(self.tag)) end,
+		__index = function (self, key) return self.tag[key] end,
+	}
+	function alias (name, tag)
+		return setmetatable({name=name, tag=tag}, mt)
+	end
+end
+
+
+local function include (source)
+	return function (target)
+		for _, header in pairs(source.headers) do
+			table.insert(target, header)
+		end
+	end
+end
+
+
+local function remove (header)
+	return function (target)
+		for key, value in pairs(target) do
+			if value == header then
+				table.remove(target, key)
+			end
+		end
+	end
+end
+
+
+local function get_or_create_tag (name)
+	local found = private.tags_lookup[name]
+	if not found then
+		found = tag(name)
+		table.insert(private.tags, found)
+		private.tags_lookup[name] = found
+	end
+	return found
+end
+
+
+function public.aliases (name)
+	local tag = get_or_create_tag(name)
+	return function (aliases)
+		for _, name in pairs(aliases) do
+			private.tags_lookup[name] = alias(name, tag)
+		end
+	end
+end
+
+
+function public.headers (name)
+	local tag = get_or_create_tag(name)
+	return function (filenames)
+		for _, header in pairs(filenames) do
+			tag:add(header)
+		end
+	end
+end
+
+
+function public.include (tag)
+	tag = private.tags_lookup[tag] or error("invalid tag: " .. tag, 2)
+	return include(tag)
+end
+
+
+function public.remove (header)
+	return remove(header)
+end
+
+
+local db = loadfile(arg[1], nil, public)
+db()
+if arg[2] then
+	local tag = private.tags_lookup[arg[2]]
+	for _, header in pairs(tag.headers) do
+		print(header)
+	end
+else
+	for _, tag in pairs(private.tags_lookup) do
+		print(tag)
+	end
+end