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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Copyright (C) 2001 Gerwin Klein <lsf@jflex.de> *
* Copyright (C) 2001 Bernhard Rumpe <rumpe@in.tum.de> *
* All rights reserved. *
* *
* License: BSD *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
import java.io.*;
/**
* Main program of the interpreter for the AS programming language.
* Based on JFlex/CUP.
*
* Steps:
* - scanning (Yylex)
* - context free parsing and AST building (yyparse)
* - build up symbol table (setSymtabs)
* - check context conditions (checkcontext)
* - prepare interpretation (prepInterp)
* - start interpretation (interpret)
*/
public class Main {
public static void main(String [] args) throws Exception {
Reader reader = null;
if (args.length == 1) {
File input = new File(args[0]);
if (!input.canRead()) {
System.out.println("Error: could not read ["+input+"]");
}
reader = new FileReader(input);
}
else {
reader = new InputStreamReader(System.in);
}
Yylex scanner = new Yylex(reader); // create scanner
SymTab symtab = new SymTab(); // set global symbol table
scanner.setSymtab(symtab);
parser parser = new parser(scanner); // create parser
Tprogram syntaxbaum = null;
try {
syntaxbaum = (Tprogram) parser.parse().value; // parse
}
catch (Exception e) {
e.printStackTrace();
}
// System.out.println(symtab);
System.out.println(syntaxbaum);
syntaxbaum.setSymtabs(); // set symbol table
// syntaxbaum.printSymtabs(); // print symbol table
syntaxbaum.checkcontext(); // CoCo (DefVar, DefFun, Arity)
if(contexterror>0) return;
syntaxbaum.prepInterp(); // var. indices and function pointers
// im Syntaxbaum setzen
syntaxbaum.interpret(); // interpretation
}
static int contexterror = 0; // number of errors in context conditions
public static void error(String s) {
System.out.println((contexterror++)+". "+s);
}
}
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