Minor fixes

src/quantity/quantity.rs

@@ -116,10 +116,10 @@ impl Quantity {
 		}
 	}
 
-	pub fn new_rational_from_string(s: &str) -> Quantity {
+	pub fn new_rational_from_string(s: &str) -> Option<Quantity> {
-		return Quantity::Rational {
+		let r = RationalQ::from_string(s);
-			v: RationalQ::from_string(s)
+		if r.is_none() { return None; }
-		}
+		return Some(Quantity::Rational { v: r.unwrap() });
 	}
 
 	pub fn new_rational_from_f64(f: f64) -> 

src/quantity/rationalq.rs

@@ -63,9 +63,13 @@ impl RationalQ {
 		return Some(RationalQ{ val: v.unwrap() });
 	}
 
-	pub fn from_string(s: &str) -> RationalQ {
+	pub fn from_string(s: &str) -> Option<RationalQ> {
 		let v = Rational::from_str_radix(s, 10);
-		return RationalQ{ val: v.unwrap() };
+		let v = match v {
+			Ok(x) => x,
+			Err(_) => return None
+		};
+		return Some(RationalQ{ val: v });
 	}
 
 	pub fn to_float(&self) -> Float {

src/tokens.rs

@@ -572,7 +572,7 @@ impl Operator{
 
 				if let Token::Number(v) = args {
 					if !v.fract().is_zero() { return Err(()); }
-					if v >= Quantity::new_rational(100, 1) { return Err(()); }
+					if v > Quantity::new_rational(50_000, 1) { return Err(()); }
 
 					let mut prod = Quantity::new_rational(1, 1);
 					let mut u = v.clone();