pg@bsg.com (Peter Garst) (04/16/91)
Introducing ydb - A SYMBOLIC DEBUGGER FOR YACC GRAMMARS AND PARSERS A COMPLETE GRAMMAR DEVELOPMENT TOOL ydb is a powerful new symbolic debugger for yacc grammars and parsers. It provides an extensive set of tools for producing correct, conflict-free grammars at translate time, and for providing complete debugging control of an operating parser at run time. ydb also provides crucial extensions to yacc, and frees the user from yacc's most serious limitations. FEATURES ******** ydb consists of two debuggers. One is for translate time, when your grammar is translated into a C language parser; the other is for run time, when you are using a program with a ydb parser compiled in. Both come with windowed interfaces, using X and SunView, and terminal interfaces. At translate time: - ydb shows you how a parse would proceed if the parser chose one branch or the other of a conflict. - ydb automatically generates a new precedence system to implement your decisions about conflicts, and writes it into your grammar file. - ydb allows you to explore your grammar; for example, one command shows you typical strings derived from a nonterminal. - ydb provides significant extensions to yacc. For example, you can compile more than one parser into a program. We built a C interpreter using two ydb parsers - one for the preprocessor feeding another for the main language. At run time: - ydb allows you to trace rule reductions, input tokens, the stack and other items of interest in your running parser. - ydb allows you to break at particular rule reductions, at all rule reductions, at particular input tokens, or at other significant points. - ydb can display the parse tree, grammar states, rules and other parser information. ydb is thoroughly documented, and comes with an indexed user's manual, a tutorial, a reference manual, a quick reference and extensive on line help. APPLICATIONS ************ - for developers and maintainers of parsers, command interpreters and front ends, ydb provides greatly enhanced productivity and ease of use, plus freedom from yacc's most serious limitations. - for educators, ydb is an ideal tool for demonstrating parsers. Your students can watch the stack grow and shrink, trace the rules as they are reduced, and in general get a window into a running parser. - for researchers, ydb provides all the tools you need to take an interactive, exploratory approach to your grammars. FOR MORE INFORMATION ******************** Bloomsbury Software Group P.O. Box 390018 Mountain View, CA 94039 (415) 964-3486 ydb@bsg.com or ...uunet!bsg!ydb