java-projects/grammer/GrammarMain.java

64 lines
2.4 KiB
Java

// Stuart Reges
// 3/10/04
//
// GrammarMain contains a main program that prompts a user for the name of a
// grammar file and then gives the user the opportunity to generate random
// versions of various elements of the grammar.
import java.io.*;
import java.util.*;
public class GrammarMain {
public static void main(String[] args) throws FileNotFoundException {
Scanner console = new Scanner(System.in);
System.out.println("Welcome to the cs145 random sentence generator.");
System.out.println();
// open grammar file
System.out.print("What is the name of the grammar file? ");
String fileName = console.nextLine();
Scanner input = new Scanner(new File(fileName));
// read the grammar file and construct the grammar solver
List<String> grammar = new ArrayList<String>();
while (input.hasNextLine())
grammar.add(input.nextLine());
GrammarSolver solver =
new GrammarSolver(Collections.unmodifiableList(grammar));
showResults(console, solver);
}
// pre : console open for console reading, solver initialized
// post: allows the user to repeatedly pick a grammar element to generate
public static void showResults(Scanner console, GrammarSolver solver) {
for(;;) {
System.out.println();
System.out.println("Available symbols to generate are:");
System.out.println(solver.getSymbols());
System.out.print("What do you want generated (return to quit)? ");
String target = console.nextLine();
if (target.length() == 0)
break;
if (!solver.grammarContains(target))
System.out.println("Illegal symbol");
else {
System.out.print("How many do you want me to generate? ");
if (!console.hasNextInt())
System.out.println("that's not an integer");
else {
int number = console.nextInt();
if (number < 0)
System.out.println("no negatives allowed");
else {
String[] answers = solver.generate(target, number);
for (int i = 0; i < number; i++)
System.out.println(answers[i]);
}
}
console.nextLine(); // to position to next line
}
}
}
}