An interpreter for Easy, the teaching notation in Evangel P. Quiwa, Data Structures (Manila: Electronics Hobbyists Publishing House, 2007). Quiwa traces that notation to SPARKS, in Ellis Horowitz and Sartaj Sahni, Fundamentals of Data Structures (Computer Science Press, 1976), pp. 8–15, and to the data-structures course Oscar Ibarra taught at the University of the Philippines in the ...