Syntax-Directed Pretty Printing—A First Step Towards a Syntax-Directed Editor

A language-independent syntax-directed pretty printer has been implemented as the first step towards building a language-independent syntax-directed editor. The syntax-directed pretty printer works in two phases: the grammar processing phase and the program processing phase. In the grammar processing stage, a grammar which contains a context-free grammar and information for the parser and pretty printer is processed and all files needed by the second phase are written. With these files, the syntax-directed pretty printer works for the language of the grammar. The syntax-directed editor would use the same grammar processing phase to construct the files needed to make it work for a specific language. In the program processing phase, programs in the language of the grammar are parsed and parse trees are built. If syntax errors are found, error messages are produced and error recovery is done. The parse trees are pretty printed according to the pretty printer specifications given in the grammar, resulting in well-indented, syntactically clear programs.