Pastel (programming language)

Pastel is an extended version of the Pascal programming language, created in 1982 for Amber, an operating system for the S-1 supercomputer project at Lawrence Livermore National Laboratory in California. The Pastel compiler was the inspiration for Richard Stallman's GNU C compiler.

Pastel was conceived by Jeffrey M. Broughton, then Project Engineer in charge of compilers and operating system software for the S-1 project, because of dissatisfaction with the PL/1 language in which Amber was being implemented. The language was named Pastel ("an off-color Pascal").

Compared with Pascal compilers of that period, Pastel's features included:
 * Improved type definition
 * Parametric types
 * Explicit packing and allocation control
 * Additional parameter passing modes
 * Additional control constructs
 * Set iteration
 * Loop-exit form
 * Return statement
 * Module definition
 * Exception handling
 * General enhancements
 * Conditional boolean operations
 * Constant expressions
 * Variable initialization