onnlucky / jmeta Goto Github PK

java  -cp jmeta-runtime.jar:test Calculator "4 * 3 - 2/2"
Exception in thread "main" jmeta.SyntaxError: expected end of input before '/2' (at line: 1, char: 9)
    at Calculator.start(Calculator.java:22)
    at jmeta.BaseParser.parse(BaseParser.java:199)
    at jmeta.BaseParser.parse(BaseParser.java:190)
   at Calculator.main(Calculator.java:8)

I've just started playing with it and, and have run into this. Interesting enough, this:

java  -cp jmeta-runtime.jar:test Calculator "4 * 3/3 - 2"
2

works

example:
rule: xs=something* ( ?{ xs.length == 0 } simple | complex) ;
will always do complex
(caveat, the predicate needs to be written like such: return ((ArrayList)xs).size() == 0;)

_t=ERROR; do{ //or
  { int _p108=_pos; _t=ERROR; do { //and
    if (!__pred107(ps,xs)) _t=ERROR;

since _t is set to ERROR at start of alternative list, and a predicate does not reset _t only set it to error if needed, this will fail

workaround: place an empty before the first predicate:
rule: xs=something* ( empty ?{ xs.length == 0 } simple | complex) ;