HP Compiler

Language highlights:

• High-level, strongly typed language with local variables, procedures, functions and programs.
• "Normal" infix syntax for expressions, and casts (type-conversions).
• High-level control structures; they have a similar form to that of User RPL.
• Direct stack manipulations are allowed, since this is often much more efficient than using local variables.
• Compiles directly to System RPL (no external programs are required) or to System RPL source compatible with GNU tools.

The language supports strings, real numbers, complex numbers, arrays, lists, binary numbers (hex strings) and system objects such as system binary. Instead of providing a code yourself, you can declare a subroutine as "external" and give its ROM address. In fact, the core language is minimal and heavily relies on this feature (something like C); the compiler automatically loads the library of many ROM routines before compiling your source.

Just to give you the flavor of the language, here are two examples (one using stack manipulations, the other using local variables). Both programs do the same thing: take a user binary number (hex string) on level 2 and real number on level 1 and shift it that many places to the left. The syntax is a mixture of C and Pascal with comments borrowed from Ada.

-- using stack manipulations
function slns(a : binary; n : real) : binary;
begin
	() = a;
	start 1, natural n do
		() = shl binary ();
	next;
end;

-- using local variables
function slnv(a : binary; n : real) : binary;
var result : binary;
begin
	result = a;
	start 1, natural n do
		result = shl result;
	next;
	() = result;
end;