import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import wyautl.core.Automaton;
import wyautl.io.PrettyAutomataWriter;
import wyautl.rw.*;
public final class Main {
public enum RewriteMode { SIMPLE, STATIC_DISPATCH };
private Main() {} // avoid instantiation of this class
public static void main(String[] args) {
final BufferedReader input =
new BufferedReader(new InputStreamReader(System.in));
try {
RewriteMode rwMode = RewriteMode.STATIC_DISPATCH;
System.out.println("Welcome!\n");
while(true) {
System.out.print("> ");
String text = input.readLine();
// commands goes here
if(text.equals("help")) {
printHelp();
} else if(text.equals("exit")) {
System.exit(0);
} else if(text.equals("rw-simple")) {
rwMode = RewriteMode.SIMPLE;
System.out.println("Rewrite mode: simple");
} else if(text.equals("rw-static-dispatch")) {
System.out.println("Rewrite mode: static-dispatch");
rwMode = RewriteMode.STATIC_DISPATCH;
} else {
reduce(text,rwMode);
}
}
} catch(IOException e) {
System.err.println("I/O Error - " + e.getMessage());
}
}
private static void reduce(String text, RewriteMode rwMode) {
try {
Parser parser = new Parser(text);
Automaton automaton = new Automaton();
int root = parser.parse(automaton);
automaton.setRoot(0, root);
PrettyAutomataWriter writer = new PrettyAutomataWriter(System.out,
Arithmetic.SCHEMA, "Or", "And");
System.out.println("------------------------------------");
writer.write(automaton);
writer.flush();
StrategyRewriter.Strategy<InferenceRule> inferenceStrategy;
StrategyRewriter.Strategy<ReductionRule> reductionStrategy;
switch (rwMode) {
case SIMPLE:
inferenceStrategy = new SimpleRewriteStrategy<InferenceRule>(
automaton, Arithmetic.inferences);
reductionStrategy = new SimpleRewriteStrategy<ReductionRule>(
automaton, Arithmetic.reductions);
break;
case STATIC_DISPATCH:
inferenceStrategy = new StaticDispatchRewriteStrategy<InferenceRule>(
automaton, Arithmetic.inferences,Arithmetic.SCHEMA);
reductionStrategy = new StaticDispatchRewriteStrategy<ReductionRule>(
automaton, Arithmetic.reductions,Arithmetic.SCHEMA);
break;
default:
// DEAD-CODE
inferenceStrategy = null;
reductionStrategy = null;
}
StrategyRewriter rw = new StrategyRewriter(automaton,
inferenceStrategy, reductionStrategy, Arithmetic.SCHEMA);
rw.apply(10000);
System.out.println("\n\n=> (" + rw.getStats() + ")\n");
writer.write(automaton);
writer.flush();
System.out.println("\n");
} catch (RuntimeException e) {
// Catching runtime exceptions is actually rather bad style;
// see lecture about Exceptions later in the course!
System.err.println("error: " + e.getMessage());
e.printStackTrace(System.err);
System.err.println("Type \"help\" for help");
} catch (IOException e) {
System.err.println("I/O Exception?");
}
}
private static void printHelp() {
System.out.println("Calculator commands:");
System.out.println("\thelp --- access this help page");
System.out.println("\texit --- quit");
}
}