The name is from CS, but the regexen in, e.g., Perl, Python, Ruby, can describe grammars that are not RE grammars in the CS sense.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Paul Gilmartin <[email protected]> Sent: Tuesday, February 25, 2020 11:51 AM To: [email protected] Subject: Re: Rexx parse using period as placeholder On Tue, 25 Feb 2020 08:14:33 -0500, Tony Thigpen wrote: >"regular expressions". What a misnamed item. It should be called "geek >readable only expressions". :-) > The name is adopted from formal language theory, clearly a geeky field. An alternative name is Chomsky type-3. https://secure-web.cisco.com/1yEhmTUBhK8QGgUQt09y0JsOgSqhJXPgIB7Wz4gZwgrTHdy8wAmwypFT0tCrS-JB2GheOTXaWsSeHJvgS2ofoCdp0m-1F0xEEQ1yXoQPhi6lbKSQQKlTBLZzS3TTM684q07ZikhoWrXEgICvTpo9FJcP95rTkyG3euEsTRYwDhlCXDQy_L5QL_LGkcmjt4G4xcTLA5yxPC3kMDpTFlLzZ31kiCv-pmGKv9GELh_RI2HeGU3cuxaX9kEFbeLzlK9eZvHT_rqfF1xTGp98og32FnHCCvu30HGdzhtB0IkRj8VaAbLArDRGTApSMFRK0kJHQ6mgZ9_m92aUcmsqyN6vlKLSyxEZtJKpHgap3ZEnOXvRq8yUe1zu3WkELf09COKLJTEn0ROC6L2B7BXUy1LsGE4Qj6Jwt3MuW_tao1O43pxGqN5xEtkLqIt86glUmt6Hu/https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FChomsky_hierarchy#Type-3_grammars It refers not to the template but to the target. I shudder to envision a formal grammer for UNIX regexen. On Tue, 25 Feb 2020 12:11:24 +0000, Seymour J Metz wrote: >What is happening is that everything in the template before the string match >'.' >is a sub-pattern applied to the fragment to the left of the period. ... > Good description. Does IBM use the term "sub-pattern" anywhere in its documentation? On Tue, 25 Feb 2020 13:24:09 +0000, Seymour J Metz wrote: >While the Eunix RE syntax is grotesque, the regexen are incredibly useful. I >just wish that >they had adopted the pattern syntax from SNOBOL or Wylbur. > There are two poles of UI design style: o Ergonomic or keystroke economy. Frequently used commands are single keystrokes with no lexical separator between the command and its argument, as in the XEDIT "/target" for a string search. o Orderly command grammar. I suspect that TSO begat CLIST and linemod EDIT, which begat ISPF commands. Good in a script; terrible from the keyboard. A very simple regex pattern, / ' " /, was formerly available in ISPF EDIT only as F x'407d407f40'! Now that ISPF has regexen, it can be the relatively transparent F R' ['] " '. But only the hex can be used as a replacement. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
