parse_result read_lvl(string input, int from, int lvl) {
from = skipSpaces(input,from);
if (from >= (int)input.length()) {
throw "End of input reached before the parsing finished";
}
if (lvl <= 0) { // parens or variable
if (input[from] == '(') {
parse_result pr = read_lvl(input,from+1,START_LVL);
pr.idx = skipSpaces(input, pr.idx);
if (pr.idx >= (int)input.length()) {
throw "End of input reached before the parsing finished";
} else if (input[pr.idx] != ')') {
throw "'(' at character "+pr.idx;
}
pr.idx = pr.idx+1;
return pr;
} else {
return read_var(input, from);
}
} else {
operateur op = operateur_for_level(lvl);
string s_op = operateur2string(op);
if (is_binary(op)) {
parse_result pr1 = read_lvl(input,from,lvl-1);
pr1.idx = skipSpaces(input,pr1.idx);
if ( input.compare(pr1.idx, s_op.length(), s_op) == 0 ) {
parse_result pr2 = read_lvl(input,pr1.idx+(int)s_op.length(), lvl);
parse_result res;
res.f = new formule();
res.f -> op = op;
res.f -> arg1 = pr1.f;
res.f -> arg2 = pr2.f;
res.idx = pr2.idx;
return res;
} else {
return pr1;
}
} else {
if ( input.compare(from, s_op.length(), s_op) == 0 ) {
parse_result pr = read_lvl(input,from + (int)s_op.length(),lvl);
parse_result res;
res.idx = pr.idx;
res.f = new formule();
res.f->op = op;
res.f->arg = pr.f;
return res;
} else {
return read_lvl(input,from,lvl-1);
}
}
}
}
string formule2string(const formule* f) {
switch (f->op) {
case o_variable:
return *(f->nom);
case o_non:
return "~" + formule2string(f->arg);
case o_et:
case o_ou:
case o_equivaut:
case o_implique:
return "(" + formule2string(f->arg1) + " " + operateur2string(f->op) + " " + formule2string(f->arg2) + ")";
}
}
