TUTOR programming language

Later renamed to PLATO Author Language. It had powerful pattern matching for text that allowed students to answer questions using complete sentences. This level of detail also applied to mathematical equations. Students could enter real equations with superscript, fractions, implicit multiplication (2b and 2×b meant the same thing), and symbols such as ÷, ×, π, and ≥ instead of encoding them or using substitute characters. The programmer could enter them in the code as such also. At first, there were no local variables, only 'private' and 'common' ones. Each user had a private data segment of 150 variables in the mainframe memory. Then all users shared 'common blocks' of the mainframe memory, where variables could be exchanged between users. The private variable were persistent and could be used in any program the user ran without being erase when loading a new program. Additionally, each program was allotted their own common block to be shared between all users of that program. Finally, 1000 temporary variables could be allotted to a program when needed; these where a way to 'bankswitch' the various variable categories. Proper common and private, local and global variables were added later.