出典:Wikipedia
出典:『Wikipedia』 (2011/02/03 23:12 UTC 版)
The Syntax Definition Formalism (SDF for short) is a metasyntax used to define context-free grammars: that is, a formal way to describe formal languages. It can express the entire range of context-free grammars. Its current version is SDF2. A parser and parser generator for SDF specifications are provided as part of the free ASF+SDF Meta Environment. These operate using the SGLR (Scannerless GLR parser). An SDF parser outputs parse trees or, in the case of ambiguities, parse forests.