Compiler Construction with ANTLR and Java

By Gary L. Schaps

Dr. Dobb's Journal March 1999

// import directive
importDirective
// init-action
{File f=null; String str=null;}
// rule
:    "import" str=fileName
    // semantic actions
    {
        f = new File(str);  KPLLexer lexer = null;
        lexer = new KPLLexer(new FileInputStream(f));
        parser = new KPLParser(lexer);
        //  this file's either another pattern file ...
        if (str.substring(str.length()-4).equals(".kpl")) { 
            parser.compilationUnit();
        }else{
            // ... or else it's a test program program ...
            parser.testProgram();
        }
    }
;

Example 3: ANTLR rule for discriminating import directive.

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