The full KWIC index program specification can be found in the original 1971 paper (reference [8] in the 1972 paper): https://kilthub.cmu.edu/articles/journal_co

The full KWIC index program specification can be found in the original 1971 paper (reference [8] in the 1972 paper): https://kilthub.cmu.edu/articles/journal_contribution/On_the_criteria_to_be_used_in_decomposing_systems_into_modules/6607958/files/12098510.pdf https://kilthub.cmu.edu/articles/journal_contribution/On_the... The code therein uses the specification language described in https://dl.acm.org/doi/pdf/10.1145/355602.361309 https://dl.acm.org/doi/pdf/10.1145/355602.361309 (reference [3] in the 1972 paper). From there: "The notation is mainly ALGOL-like and requires little explanation. To distinguish references to the value of a function before calling the specified function from references to its value after the call, we enclose the old or previous value in single quotes (e.g. 'VAL'). If the value does not change, the quotes are optional. Brackets ("[" and "]") are used to indicate the scope of quantifiers. "=" is the relation "equals" and not the assignment operator as in FORTRAN."