XPL0

XPL0 is a computer programming language that is essentially a cross between Pascal and C. It was created in 1976 by Peter J. R. Boyle who wanted a high-level language for his microcomputer and wanted something more sophisticated than BASIC, which was the dominant language for personal computers at the time.

XPL0 is based on PL/0, an example compiler in the book Algorithms + Data Structures = Programs by Niklaus Wirth. The first XPL0 compiler was written in ALGOL. It generated instructions for a pseudo-machine that was implemented as an interpreter on a Digital Group computer based on the 6502 microprocessor. The compiler was converted from ALGOL to XPL0 and was then able to compile itself and run on a microcomputer.

XPL0 soon proved its worth in a variety of products based on the 6502. These embedded systems would otherwise have had their code written in assembly language, which is much more tedious to do.

Boyle used XPL0 to write a disk operating system called Apex. Beginning in 1980 this was sold, along with XPL0, as an alternative to Apple DOS for the Apple II computer, which was based on the 6502.

XPL

XPL is a programming language based on PL/I, and a portable one-pass compiler written in its own language, and a parser generator tool for easily implementing similar compilers for other languages. XPL was designed in 1967 as a way to teach compiler design principles and as starting point for students to build compilers for their own languages.

XPL was designed and implemented by William McKeeman and David B. Wortman at University of California, Santa Cruz and James J. Horning and others at Stanford University. XPL was first announced at the 1968 Fall Joint Computer Conference. The methods and compiler are described in detail in the 1971 textbook A Compiler Generator.

They called the combined work a 'compiler generator'. But that implies little or no language- or target-specific programming is required to build a compiler for a new language or new target. A better label for XPL is a Translator Writing System. It helps you write a compiler with less new or changed programming code.

XPL (disambiguation)

XPL may refer to:

Computing

Places

Other