public void parse() throws IOException {
sta.nextTokenType();
cond();
if (sta.lastToken() != TOKEN_EOF)
throw new InvalidExpressionError(
"Expected end of expression. Got '" + sta.lastToken() + "' instead.");
}
private void factb() throws IOException {
switch (sta.lastToken()) {
case TOKEN_NOT:
sta.nextTokenType();
factb();
builder.buildOperator(OP_NOT);
break;
case TOKEN_OPAR:
sta.nextTokenType();
cond();
if (sta.lastToken() != TOKEN_CPAR)
throw new InvalidExpressionError("Expected ). Got '" + sta.lastToken() + "' instead.");
sta.nextTokenType();
break;
case TOKEN_ADD:
case TOKEN_SUB:
case TOKEN_ID:
case TOKEN_NUM:
case TOKEN_OSB:
expr();
switch (sta.lastToken()) {
case TOKEN_EQ:
builder.buildOperator(OP_EQ);
break;
case TOKEN_NE:
builder.buildOperator(OP_NE);
break;
case TOKEN_GT:
builder.buildOperator(OP_GT);
break;
case TOKEN_GE:
builder.buildOperator(OP_GE);
break;
case TOKEN_LT:
builder.buildOperator(OP_LT);
break;
case TOKEN_LE:
builder.buildOperator(OP_LE);
break;
default:
throw new InvalidExpressionError(
"Expected relational operator (==, !=, >, >=, <, <=). Got '"
+ sta.lastToken()
+ "' instead.");
}
sta.nextTokenType();
expr();
builder.endOperator();
break;
default:
throw new InvalidExpressionError(
"Expected not (!), (, [, +, -, a number or an identifier. Got '"
+ sta.lastToken()
+ "' instead.");
}
}