initial release

cosmic rage/lua/json/decode/calls.lua

@@ -0,0 +1,116 @@
+--[[
+	Licensed according to the included 'LICENSE' document
+	Author: Thomas Harning Jr <harningt@gmail.com>
+--]]
+local lpeg = require("lpeg")
+local tostring = tostring
+local pairs, ipairs = pairs, ipairs
+local next, type = next, type
+local error = error
+
+local util = require("json.decode.util")
+
+local buildCall = require("json.util").buildCall
+
+local getmetatable = getmetatable
+
+module("json.decode.calls")
+
+local defaultOptions = {
+	defs = nil,
+	-- By default, do not allow undefined calls to be de-serialized as call objects
+	allowUndefined = false
+}
+
+-- No real default-option handling needed...
+default = nil
+strict = nil
+
+local isPattern
+if lpeg.type then
+	function isPattern(value)
+		return lpeg.type(value) == 'pattern'
+	end
+else
+	local metaAdd = getmetatable(lpeg.P("")).__add
+	function isPattern(value)
+		return getmetatable(value).__add == metaAdd
+	end
+end
+
+local function buildDefinedCaptures(argumentCapture, defs)
+	local callCapture
+	if not defs then return end
+	for name, func in pairs(defs) do
+		if type(name) ~= 'string' and not isPattern(name) then
+			error("Invalid functionCalls name: " .. tostring(name) .. " not a string or LPEG pattern")
+		end
+		-- Allow boolean or function to match up w/ encoding permissions
+		if type(func) ~= 'boolean' and type(func) ~= 'function' then
+			error("Invalid functionCalls item: " .. name .. " not a function")
+		end
+		local nameCallCapture
+		if type(name) == 'string' then
+			nameCallCapture = lpeg.P(name .. "(") * lpeg.Cc(name)
+		else
+			-- Name matcher expected to produce a capture
+			nameCallCapture = name * "("
+		end
+		-- Call func over nameCallCapture and value to permit function receiving name
+
+		-- Process 'func' if it is not a function
+		if type(func) == 'boolean' then
+			local allowed = func
+			func = function(name, ...)
+				if not allowed then
+					error("Function call on '" .. name .. "' not permitted")
+				end
+				return buildCall(name, ...)
+			end
+		else
+			local inner_func = func
+			func = function(...)
+				return (inner_func(...))
+			end
+		end
+		local newCapture = (nameCallCapture * argumentCapture) / func * ")"
+		if not callCapture then
+			callCapture = newCapture
+		else
+			callCapture = callCapture + newCapture
+		end
+	end
+	return callCapture
+end
+
+local function buildCapture(options)
+	if not options  -- No ops, don't bother to parse
+		or not (options.defs and (nil ~= next(options.defs)) or options.allowUndefined) then
+		return nil
+	end
+	-- Allow zero or more arguments separated by commas
+	local value = lpeg.V(util.types.VALUE)
+	local argumentCapture = (value * (lpeg.P(",") *  value)^0) + 0
+	local callCapture = buildDefinedCaptures(argumentCapture, options.defs)
+	if options.allowUndefined then
+		local function func(name, ...)
+			return buildCall(name, ...)
+		end
+		-- Identifier-type-match
+		local nameCallCapture = lpeg.C(util.identifier) * "("
+		local newCapture = (nameCallCapture * argumentCapture) / func * ")"
+		if not callCapture then
+			callCapture = newCapture
+		else
+			callCapture = callCapture + newCapture
+		end
+	end
+	return callCapture
+end
+
+function load_types(options, global_options, grammar)
+	local capture = buildCapture(options, global_options)
+	if capture then
+		util.append_grammar_item(grammar, "VALUE", capture)
+	end
+end