TUTOR (programming Language) - Structure of A TUTOR Lesson

Structure of A TUTOR Lesson

A TUTOR lesson consists of a sequence of units where each unit begins with the presentation of information and progress from one unit to the next is contingent on correctly answering one or more questions. As with COBOL paragraphs, control may enter a TUTOR unit from the preceding unit and exit into the next, but units are also callable as subroutines using the do or join commands.

Here is an example unit from page 5 of the TUTOR User's Memo, March 1973 (Computer-based Education Research Laboratory, University of Illinois at Urbana-Champaign):

unit math at 205 write Answer these problems 3 + 3 = 4 × 3 = arrow 413 answer 6 arrow 613 answer 12

Several things should be immediately apparent from this example.

• First, TUTOR is a fixed format language. Each line begins with a command name, with the arguments to that command (the tag) following, after a tab.
• In some cases, such as the write command above, the tag may consist of multiple lines. Continuation lines are either blank or have a leading tab.
• Screen coordinates are presented as single numbers, so 205 refers to line 2 column 5, and 413 refers to line 4 column 13.

What may not be apparent is the control structure implicit in this unit. The arrow command marks the entrance to a judging block This control structure is one of TUTOR's unique features.