Easy-Lang: Evangel Quiwa's Programming Language

Easy-Lang is a Python interpreter for “Easy,” the teaching notation used in Evangel P. Quiwa’s 2007 data-structures textbook. The notation traces back to SPARKS and to a University of the Philippines data-structures course taught in the 1970s. The interpreter runs programs written in this notation; it does not include the textbook. Programs are organized into procedures and begin execution at MAIN. They can express conditionals, several loop forms, arrays, structures, linked nodes, input and output, and procedure calls. Parameters are passed by reference, while expressions passed as arguments are evaluated into temporary cells.

The tool is designed to help students run and understand algorithm examples. It can execute local files or GitHub-hosted programs, and an explanation mode prints a step-by-step trace alongside the program’s output. An interview mode produces concise talking points for cataloged examples, including key steps, complexity, and pitfalls. The README demonstrates insertion sort and binary search, and describes the trace notation, where arrows show assigned or returned values and loop conditions are marked true or false. Installation creates an isolated Python environment, avoiding changes to system-managed packages; the interpreter can also be run from a cloned repository. A Python interface exposes the program’s output, trace, return value, and global variables, and the project includes examples and unit tests.