APAREL-A PARSE-REQUEST LANGUAGE
RAND CORP SANTA MONICA CA
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A description, without listing, of APAREL, a flexible high-level parsing-language extension to PLI that provides the pattern-matching capability normally found only in special-purpose languages such as SNOBOL4 and TMG. This capability is provided through parse requests stated in a BNF-like format, which form their own programming language with special sequencing rules. Upon successful completion of a parse request, an associated piece of PLI code is executed, which has as normal PLI strings the various elements of the parse at all levels. It has as normal PLI variables the information concerning which of the various alternative parsings were successful. Convenient facilities for multiple input-output streams, the initiation of sequences of parse request as a subroutine, and parse-time semantic checks are included. APAREL has proved convenient in building a powerful SYNTAX and FUNCTION macro system, an algebraic language preprocessor debugging system, an on-line command parser which produces actions rather than machine code, and a translator for Dataless Programming RM- 5290-ARPA, and as a general string manipulator.
- Computer Programming and Software