Initial problem

Author: AydinHassan

exercises/unite-the-types/problem/problem.md

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+For a long time in PHP the types have been independent & solitary, it's now time for the uprising, and the uniting of types.
+
+Create a program which adds up and prints the result of all the arguments passed to the program (not including the program name).
+
+In the process you should create a function named `adder` which accepts these numbers as a variadic parameter.
+
+The type of the parameter should be a union of all the types of numbers we might pass to your program.
+
+We will pass to your program any number of random numbers which could be integers, floats or strings. Your `adder` function
+should only accept these types.
+
+You should output the sum of the numbers followed by a new line.
+
+How you print and add the numbers is up to you.
+
+### The advantages of match
+
+* Match uses strict equality, unlike switch which uses weak comparison and can lead to subtle bugs.
+* Each match arm does not fall through without a break statement, unlike switch.
+* Match expressions must be exhaustive, if there is no default arm specified, and no arm matches the given value, an `UnhandledMatchError` is thrown
+* Match is an expression and thus returns a value, reducing unnecessary variables and reducing the risk of accessing undefined variables.
+
+
+----------------------------------------------------------------------
+## HINTS
+
+Remember the first argument will be the programs file path and not an argument passed to the program.
+
+The function must be called `adder`.
+
+It is up to you to pass the numbers to your function.
+
+Documentation on the union types can be found by pointing your browser here:
+[https://www.php.net/manual/en/language.types.declarations.php#language.types.declarations.union]()
+
+----------------------------------------------------------------------
+## EXTRA
+
+You should access `$argv` directly to fetch the numbers (we have casted the arguments from strings to their respective types)
+
+Think about the return type of your `adder` function - you could declare it as a float.