wsmith@uiucdcsm.UUCP (05/20/88)
Leif is a language oriented editor that has been just made available via anonymous ftp from a.cs.uiuc.edu. Leif is based on an incremental parser. A language for Leif is specified with a lexical analyzer via Lex and an LALR(1) parser via Bison (which uses the Yacc input format). Editing of a program in Leif is done with GNU Emacs. A minor mode adds commands to GNU Emacs to access the syntax of the program. Commands exist to locate errors, to display the legal tokens at the cursor (i.e. the followset), and to highlight phrases in the program being edited. (See the Software Engineering Digest for a more complete description of Leif.) Of interest to comp.lang.misc is that Leif's language descriptions are completely table driven. It is possible to prototype an LALR grammar for a language and very quickly have a language oriented editor for the language. The "legal tokens" command is also useful to help intermediate students learn a language. Language descriptions are provided for Pascal, Ada, and a large subset of C. On a.cs.uiuc.edu, the files are located in the subdirectory pub/Leif. The file README.DIST describes the files located there to help select the files needed. (If you are unable to access the files via ftp, please contact us.) Please send Leif related queries to ihnp4!uiucdcs!leif or leif@a.cs.uiuc.edu William Smith, Dan LaLiberte, Roy Campbell