// Primary : (LitString | "(" Term ")" | Primitive) ["*" | "+" | Repetitions] ;
internal RegExTree Primary() {
RegExTree tmp;
Unary pls;
if (!esc && chr == '"')
tmp = LitString();
else if (!esc && chr == '(') {
scan();
tmp = Term();
checkAndScan( ')' );
}
else
tmp = Primitive();
if (!esc && chr == '*') {
scan();
tmp = new Unary( RegOp.closure, tmp );
}
else if (!esc && chr == '+') {
pls = new Unary( RegOp.closure, tmp );
pls.minRep = 1;
scan();
tmp = pls;
}
else if (!esc && chr == '?') {
pls = new Unary( RegOp.finiteRep, tmp );
pls.minRep = 0;
pls.maxRep = 1;
scan();
tmp = pls;
}
else if (!esc && chr == '{' && Char.IsDigit( peek() )) {
pls = new Unary( RegOp.finiteRep, tmp );
GetRepetitions( pls );
tmp = pls;
}
return tmp;
}
// Repetitions : "{" IntLiteral ["," [IntLiteral] ] "}" ;
internal void GetRepetitions( Unary tree ) {
scan(); // read past '{'
tree.minRep = GetInt();
if (!esc && chr == ',') {
scan();
if (Char.IsDigit( chr ))
tree.maxRep = GetInt();
else
tree.op = RegOp.closure;
}
else
tree.maxRep = tree.minRep;
checkAndScan( '}' );
}
// Expr : ["^"] SimpleExpr ["$"] ;
internal RegExTree Expr() {
RegExTree tmp;
if (!esc && chr == '^') {
scan();
tmp = new Unary( RegOp.leftAnchor, Simple() );
}
else
tmp = Simple();
if (!esc && chr == '$') {
scan();
tmp = new Unary( RegOp.rightAnchor, tmp );
}
return tmp;
}