Module:DiceEval

Documentation for this module may be created at Module:DiceEval/doc

local p = {}

local function parseDice(s)
	-- Accepts optional spaces and upper/lowercase 'd'
	if type(s) ~= 'string' then
		return nil, nil, "expected a string like '2d8'"
	end
	local n, m = s:match("^%s*(%d+)%s*[dD]%s*(%d+)%s*$")
	if not n then
		return nil, nil, "bad format (use NdM, e.g., '3d6')"
	end
	n, m = tonumber(n), tonumber(m)
	if n <= 0 or m <= 0 then
		return nil, nil, "n and m must be positive integers"
	end
	return n, m
end

local function compute(n, m)
	return n * math.ceil((m + 1) / 2)
end

-- Public: {{#invoke:DiceMid|eval|2d8}}
function p.eval(frame)
	local s = frame.args[1] or frame.args.s
	if not s and frame.getParent then
		local parent = frame:getParent()
		if parent then s = parent.args[1] or parent.args.s end
	end

	local n, m, err = parseDice(s)
	if not n then
		return "Error: " .. err
	end
	return tostring(compute(n, m))
end

-- For other modules/tests: require('Module:DiceMid')._eval("3d6")
function p._eval(s)
	local n, m, err = parseDice(s)
	if not n then error(err) end
	return compute(n, m)
end

return p