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Check
This function checks the given arguments and calls the error-function if something is wrong. Finally it makes debugging easier since you'll get useful error-messages when calling a selfmade function with wrong or malformed arguments.
Syntax
void Check( string funcname, var types1, var arg1, string argname1, [ ... ] )
Required Arguments
- funcname: Name of the function in which the Check-function is called.
- types1: Type(s) that arg1 should/may be of. It's a string if only one type is possible, otherwise it can be a table with strings. Possible types are "nil", "boolean", "number", "string", "function", "table", "thread" and "userdata".
- arg1: Value of the argument that should be checked.
- argname1: Name of the argument whose value is arg1.
Optional Arguments
- ...: You may pass as many triples as you want to.
Source
function Check(funcname, ...)
local arg = {...}
if (type(funcname) ~= "string") then
error("Argument type mismatch at 'Check' ('funcname'). Expected 'string', got '"..type(funcname).."'.", 2)
end
if (#arg % 3 > 0) then
error("Argument number mismatch at 'Check'. Expected #arg % 3 to be 0, but it is "..(#arg % 3)..".", 2)
end
for i=1, #arg-2, 3 do
if (type(arg[i]) ~= "string" and type(arg[i]) ~= "table") then
error("Argument type mismatch at 'Check' (arg #"..i.."). Expected 'string' or 'table', got '"..type(arg[i]).."'.", 2)
elseif (type(arg[i+2]) ~= "string") then
error("Argument type mismatch at 'Check' (arg #"..(i+2).."). Expected 'string', got '"..type(arg[i+2]).."'.", 2)
end
if (type(arg[i]) == "table") then
local aType = type(arg[i+1])
for _, pType in next, arg[i] do
if (aType == pType) then
aType = nil
break
end
end
if (aType) then
error("Argument type mismatch at '"..funcname.."' ('"..arg[i+2].."'). Expected '"..table.concat(arg[i], "' or '").."', got '"..aType.."'.", 3)
end
elseif (type(arg[i+1]) ~= arg[i]) then
error("Argument type mismatch at '"..funcname.."' ('"..arg[i+2].."'). Expected '"..arg[i].."', got '"..type(arg[i+1]).."'.", 3)
end
end
end
local arg = {...}
if (type(funcname) ~= "string") then
error("Argument type mismatch at 'Check' ('funcname'). Expected 'string', got '"..type(funcname).."'.", 2)
end
if (#arg % 3 > 0) then
error("Argument number mismatch at 'Check'. Expected #arg % 3 to be 0, but it is "..(#arg % 3)..".", 2)
end
for i=1, #arg-2, 3 do
if (type(arg[i]) ~= "string" and type(arg[i]) ~= "table") then
error("Argument type mismatch at 'Check' (arg #"..i.."). Expected 'string' or 'table', got '"..type(arg[i]).."'.", 2)
elseif (type(arg[i+2]) ~= "string") then
error("Argument type mismatch at 'Check' (arg #"..(i+2).."). Expected 'string', got '"..type(arg[i+2]).."'.", 2)
end
if (type(arg[i]) == "table") then
local aType = type(arg[i+1])
for _, pType in next, arg[i] do
if (aType == pType) then
aType = nil
break
end
end
if (aType) then
error("Argument type mismatch at '"..funcname.."' ('"..arg[i+2].."'). Expected '"..table.concat(arg[i], "' or '").."', got '"..aType.."'.", 3)
end
elseif (type(arg[i+1]) ~= arg[i]) then
error("Argument type mismatch at '"..funcname.."' ('"..arg[i+2].."'). Expected '"..arg[i].."', got '"..type(arg[i+1]).."'.", 3)
end
end
end
Example
This example shows the Check-function's usage in case of a more or less useless division function.
function divide(dividend, divisor, round)
-- check the passed arguments
Check("divide", "number", dividend, "dividend", "number", divisor, "divisor", {"nil","boolean"}, round, "round")
-- error if divisor is 0
if (divisor == 0) then error("Someone tried to divide by 0. YOU MUST NOT DO THAT!!!") end
-- calculate the result
local quotient = dividend / divisor
-- round the result if round is true
if (round) then quotient = math.floor(quotient + .5)
-- return the result
return quotient
end
-- check the passed arguments
Check("divide", "number", dividend, "dividend", "number", divisor, "divisor", {"nil","boolean"}, round, "round")
-- error if divisor is 0
if (divisor == 0) then error("Someone tried to divide by 0. YOU MUST NOT DO THAT!!!") end
-- calculate the result
local quotient = dividend / divisor
-- round the result if round is true
if (round) then quotient = math.floor(quotient + .5)
-- return the result
return quotient
end
