Cooler errors?

lua/entities/gmod_wire_expression2/base/compiler.lua

@@ -1868,12 +1868,18 @@ local CompileVisitors = {
 				---@type E2Lambda
 				local f = expr(state)
 
-				if not f then
-					state:forceThrow("Trying to call function that doesn't exist!")
-				elseif f.arg_sig ~= sig then
-					state:forceThrow("Incorrect arguments passed to lambda, expected (" .. f.arg_sig .. ") got (" .. sig .. ")")
+				if f.arg_sig ~= sig then
+					if f == E2Lib.NoLambda then
+						f.fn()
+					else
+						state:forceThrow("Incorrect arguments passed to lambda, expected (" .. f.arg_sig .. ") got (" .. sig .. ")")
+					end
 				elseif f.ret ~= ret_type then
-					state:forceThrow("Expected type " .. (ret_type or "void") .. " from lambda, got " .. (f.ret or "void"))
+					if f == E2Lib.NoLambda then
+						f.fn()
+					else
+						state:forceThrow("Expected type " .. (ret_type or "void") .. " from lambda, got " .. (f.ret or "void"))
+					end
 				else
 					local rargs = {}
 					for k = 1, nargs do

lua/entities/gmod_wire_expression2/core/e2lib.lua

@@ -81,12 +81,20 @@ function Function:__tostring()
 	return "function(" .. self.arg_sig .. ")" .. ((self.ret and (": " .. self.ret)) or "")
 end
 
+---@param args string
+---@param ret string?
+---@param fn fun(args: any[]): any
 function Function.new(args, ret, fn)
 	return setmetatable({ arg_sig = args, ret = ret, fn = fn }, Function)
 end
 
 E2Lib.Lambda = Function
 
+local noLambda = Function.new("", nil, function()
+	E2Lib.RuntimeContext:forceThrow("Trying to call function that doesn't exist")
+end)
+E2Lib.NoLambda = noLambda
+
 --- Call the function without doing any type checking.
 --- Only use this when you check self:Args() yourself to ensure you have the correct signature function.
 function Function:UnsafeCall(args)

lua/entities/gmod_wire_expression2/core/functions.lua

@@ -4,13 +4,27 @@
 		Format: { arg_sig: string, ret: string, fn: fun(args: any[]): any }
 ]]
 
-registerType("function", "f", nil,
+local noLambda = E2Lib.NoLambda
+
+local function is_invalid(v)
+	return not istable(v) or getmetatable(v) ~= E2Lib.Lambda
+end
+
+-- Do this manually or otherwise registerType will needlessly copy noFunction for each zero
+WireLib.DT.FUNCTION = {
+	Zero = function()
+		return noLambda
+	end,
+	Validator = function(v)
+		return not is_invalid(v)
+	end
+}
+
+registerType("function", "f", noLambda,
 	function(self) self.entity:Error("You may not input a function") end,
 	function(self) self.entity:Error("You may not output a function") end,
 	nil,
-	function(v)
-		return not istable(v) or getmetatable(v) ~= E2Lib.Lambda
-	end
+	is_invalid
 )
 
 __e2setcost(1)
@@ -46,8 +60,12 @@ e2function string function:getReturnType()
 	return this.ret or ""
 end
 
+e2function function nofunction()
+	return noLambda
+end
+
 e2function string toString(function func)
 	return tostring(func)
 end
 
-e2function string function:toString() = e2function string toString(function func)
+e2function string function:toString() = e2function string toString(function func)