Paper: Directed Replacement

ACL ID P96-1015
Title Directed Replacement
Venue Annual Meeting of the Association of Computational Linguistics
Session Main Conference
Year 1996

This paper introduces to the finite-state calculus a family of directed replace op- erators. In contrast to the simple re- place expression, UPPER -> LOWER, defined in Karttunen (1995), the new directed ver- sion, UPPER ©-> LOWER, yields an unam- biguous transducer if the lower language consists of a single string. It transduces the input string from left to right, mak- ing only the longest possible replacement at each point. A new type of replacement expression, UPPER @-> PREFIX... SUFFIX, yields a transducer that inserts text around strings that are instances of UPPER. The symbol ... denotes the matching part of the input which itself remains unchanged. PREFIX and SUFFIX are regular expressions describ- ing the insertions. Expressions of the type UPPER @-> PI~EFIX •.. SUFFIX may be us...