{{stub|language}}

{{language|RPL
|exec=interpreted
|gc=yes
|parampass=value
|safety=unsafe
|strength=weak
|tags=rpl
|hopl id=2456
|LCT=no
|site=https://en.wikipedia.org/wiki/RPL_(programming_language)
}}

'''RPL''' (an acronym for '''Reverse Polish Lisp''') is the onboard calculator language for the HP-28 and [[wp:HP 48 series|HP 48]] lines of graphing calculators. It is a stack language (not a [[Lisp]]-like language, as its name implies), tightly integrated with the calculator system, with many instructions similar to Forth.

It can natively handle unsigned integers (named ''binary integers''), floating-point numbers (named ''real numbers''), complex numbers, vectors and matrices (named ''arrays''), lists and algebraic expressions.

There are actually two languages with the name RPL: '''User RPL''' and '''System RPL'''. System RPL is used in implementing the operating system, and User RPL is the language users use to write programs on the calculator.

The language [[RPL/2]] is a recreation of this language for POSIX machines.

{{language programming paradigm|concatenative}}