func.orchid

-- An Orchid program demonstrating the use of the `func!` keyword.

import! orchid.console;

main! {
	-- Functions can only be invoked as part of an expression. Invoking a function is as simple as
	-- stating the name of the function and then the arguments, separated by spaces.
	-- If there are multiple layers of function calls, or if the programmer simply wishes to be
	-- explicit, a function call can be delimited with parentheses. It is idiomatic to omit the
	-- parentheses in simple cases.
	bind! message = silly_join "Hello, " "Orchid";
	call! console.write_line message;
}

-- The `func! NAME (ARG: TYPE...) : RET { CODE... }` statement defines a new function. Orchid
-- functions are much more similar to functions from languages like Haskell: they cannot have
-- mutable bindings, they cannot touch external mutable state, they cannot operate directly on
-- unsafe pointers (but can interact with safe wrapper types), and they cannot have side effects
-- (i.e. invoking procedures).
--
-- The return type delimiter is a colon instead of the more typical arrow to keep the tokenizer
-- simpler (since `-` is already used to detect negative integers and floats).
func! silly_join (lhs: String, rhs: String) : String {
	-- Unlike Haskell, functions are still made up of multiple sequential statements; these statements
	-- are just restricted to a pure subset of all statements.
	return! lhs + rhs;
}