Coco/R

Abstract: Coco/R 1 is a compiler generator, which takes an attributed grammar of a source language and generates a scanner and a parser for this language. The scanner works as a deterministic finite automaton. The parser uses recursive descent. LL(1) conflicts can be resolved by a multi-symbol lookahead or by semantic checks. Thus the class of accepted grammars is LL(k) for an arbitrary k. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the As an exception, it is allowed to write an extension of Coco/R that is used as a plugin in non-free software. If not otherwise stated, any source code generated by Coco/R (other than Coco/R itself) does not fall under the GNU General Public License.

Abstract: Recursive descent parsing has the advantage of more convenient semantic processing than in the case of bottom-up parsing. However, it is limited to LL(1) grammars, which has often prevented its use for popular programming languages, such as Java or C#. The authors extended their compiler generator Coco/R, which generates recursive descent parsers, so that the user can specify rules for LL(1) conflict resolution. The simple technique works by evaluating user-defined Boolean expressions to allow the parser to make its parsing decisions where a one-symbol lookahead does not suffice. Thus multi-symbol lookahead or even semantic information can now guide the parsing process as well. Using their extended compiler generator, the authors implemented a compiler front end for C# that can be used as a framework for implementing a variety of tools, two of which are described in more detail: a white-box testing tool that measures path coverage, and a performance hint tool that evaluates source code according to user-defined rules about performance enhancements or coding style.

Abstract: We propose a solution for analyzing programs with multiple language contexts as they occur, for example, in C# 3.0. C# 3.0 has two contexts: the normal C# context and the language integrated query (Linq) context, which are basically the same, but Linq has some additional keywords that are treated as identifiers in the C# context. We demonstrate our solution by using the compiler generator Coco/R, which provides no support for enabling or disabling tokens in a grammar, as tokens are a global property of a programming language. We show how to handle additional tokens on top of the infrastructure provided by Coco/R.