private void expr() throws IOException {
switch (sta.lastToken()) {
case TOKEN_SUB:
// 0 - term
builder.buildOperand(0);
builder.buildOperator(OP_SUB);
sta.nextTokenType();
term();
builder.endOperator();
expr1();
break;
case TOKEN_ADD:
sta.nextTokenType();
term();
expr1();
break;
case TOKEN_ID:
case TOKEN_NUM:
case TOKEN_OSB:
term();
expr1();
break;
default:
throw new InvalidExpressionError(
"Expected [, a number with sign or an identifier. Got '"
+ sta.lastToken()
+ "' instead.");
}
}
private void expr1() throws IOException {
if (sta.lastToken() == TOKEN_ADD) builder.buildOperator(OP_ADD);
else if (sta.lastToken() == TOKEN_SUB) builder.buildOperator(OP_SUB);
else return;
sta.nextTokenType();
term();
builder.endOperator();
expr1();
}