public class BasicParser {
HashSet<String> reserved = new HashSet<String>();
Operators operators = new Operators();
Parser expr0 = rule();
Parser primary =
rule(PrimaryExpr.class)
.or(
rule().sep("(").ast(expr0).sep(")"),
rule().number(NumberLiteral.class),
rule().identifier(Name.class, reserved),
rule().string(StringLiteral.class));
Parser factor = rule().or(rule(NegativeExpr.class).sep("-").ast(primary), primary);
Parser expr = expr0.expression(BinaryExpr.class, factor, operators);
Parser statement0 = rule();
Parser block =
rule(BlockStmnt.class)
.sep("{")
.option(statement0)
.repeat(rule().sep(";", Token.EOL).option(statement0))
.sep("}");
Parser simple = rule(PrimaryExpr.class).ast(expr);
Parser statement =
statement0.or(
rule(IfStmnt.class).sep("if").ast(expr).ast(block).option(rule().sep("else").ast(block)),
rule(WhileStmnt.class).sep("while").ast(expr).ast(block),
simple);
Parser program = rule().or(statement, rule(NullStmnt.class)).sep(";", Token.EOL);
public BasicParser() {
reserved.add(";");
reserved.add("}");
reserved.add(Token.EOL);
operators.add("=", 1, Operators.RIGHT);
operators.add("==", 2, Operators.LEFT);
operators.add(">", 2, Operators.LEFT);
operators.add("<", 2, Operators.LEFT);
operators.add("+", 3, Operators.LEFT);
operators.add("-", 3, Operators.LEFT);
operators.add("*", 4, Operators.LEFT);
operators.add("/", 4, Operators.LEFT);
operators.add("%", 4, Operators.LEFT);
}
public ASTree parse(Lexer lexer) throws ParseException {
return program.parse(lexer);
}
}
public ASTree parse(Lexer lexer) throws ParseException {
return program.parse(lexer);
}