Topic: fixed logic language

Summary

For simple applications a fixed logic language is often advantageous. The most common is RPG with a fixed cycle of input, process, control, and output. Another is AWK on Unix, where text lines are sequentially processed by a set of pattern guarded actions. Another is CONTROL, based on event-guarded actions. Each of these has fixed flow of control into which the user plugs his actions. All machines and command languages become fixed logic if used sequentially. Fixed logic languages become complicated when 'hooks' are used to modify control flow.

Advantages-- Provides a flexible system which does not require programmers, since only actions are specified. (cbb 5/80)

Subtopic: AWK -- pattern and action

Quote: AWK program consists of patterns and actions; if an input line matches a pattern, its action occurs [»ahoAV4_1979]

Quote: AWK is used for report generation, data transformation, and data validation [»ahoAV4_1979, OK]

Quote: AWK is designed for simple information retrieval, text manipulation, and report generation [»ahoAV4_1979]

Quote: AWK avoids the trappings of conventional programming languages; uses simple, concise expressions and default handling of common cases

Quote: AWK programs can be very complicated even though basic design is simple

Subtopic: examples

Quote: RPG defines a fixed logic flow machine; heading, detail output, input, flags, totals [»seedH_1971, OK]

QuoteRef: seedH_1971 ;;37 program by specification of processor info, file descriptions, line counter (paging control), input specification, output specification and calculations.

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