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Main.java
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Main.java
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/* Copyright (C) 2012 Matt O'Connor <thegreendragon@gmail.com> */
package zero.compiler;
import java.io.Console;
import java.io.InputStream;
import java.io.FileInputStream;
import zero.lang.*;
import zero.compiler.parser.*;
import zero.interp.ast.*;
public final class Main {
static final Console C = System.console();
static final String PROMPT = "> ";
static final String NL = System.lineSeparator();
public static void main(final String[] args) throws Exception {
C.printf(welcome());
Scope scope = Pervasives.addAll(Scope.EMPTY);
if(args.length > 0) {
for(final String file : args) {
final Expression expr = read(new FileInputStream(file));
eval(expr);
}
}
C.printf(PROMPT);
String line;
while((line = C.readLine()) != null) {
handleSpecial(line);
try {
final Expression expr = read(line);
eval(expr);
} catch(final ParseException exn) {
C.printf("Error: %s%n", exn.getMessage());
}
C.printf(PROMPT);
}
}
private static Expression read(final InputStream in) {
final Lexer l = new Lexer(in);
final Parser p = new Parser(l);
final Expression expr = p.parseExpression();
return expr;
}
private static Expression read(final String line) {
final Lexer l = new Lexer(line);
final Parser p = new Parser(l);
final Expression expr = p.parseExpression();
return expr;
}
private static void eval(final Expression expr) {
C.printf("%s%n", expr);
}
private static void handleSpecial(final String line) {
if(line.equals("#exit")) {
System.exit(0);
}
}
private static String welcome() {
final StringBuilder b = new StringBuilder();
b.append("zero repl v").append(Version.string()).append(NL);
b.append(" Copyright (C) 2012 Matt O'Connor <thegreendragon@gmail.com>").append(NL);
return b.toString();
}
}