Implement number casting.

src/bin.rs

@@ -315,7 +315,22 @@ impl Loopable for serde_json::Value {
 
 impl Castable for serde_json::Value {
     fn cast_to_type<'a>(&'a self, target: &str) -> Option<IceResult<'a>> {
-        todo!()
+        match (self, target) {
+            (serde_json::Value::String(text), "number") => text
+                .parse::<u64>()
+                .map(|num| IceResult::from_owned(OwnedLiteral::LPositiveInteger(num)))
+                .or_else(|_| {
+                    text.parse::<i64>()
+                        .map(|num| IceResult::from_owned(OwnedLiteral::LNegativeInteger(num)))
+                })
+                .or_else(|_| {
+                    text.parse::<f64>()
+                        .map(|num| IceResult::from_owned(OwnedLiteral::LFloat(num)))
+                })
+                .ok(),
+            (serde_json::Value::Number(_), "number") => Some(IceResult::from_borrowed(self)),
+            (_, _) => panic!("Unimplemented cast"),
+        }
     }
 }
 

src/renderer/parameters_context.rs

@@ -170,7 +170,24 @@ impl Walkable for OwnedLiteral {
 
 impl Castable for OwnedLiteral {
     fn cast_to_type<'a>(&'a self, target: &str) -> Option<IceResult<'a>> {
-        todo!()
+        match (self, target) {
+            (OwnedLiteral::LString(text), "number") => text
+                .parse::<u64>()
+                .map(|num| IceResult::from_owned(OwnedLiteral::LPositiveInteger(num)))
+                .or_else(|_| {
+                    text.parse::<i64>()
+                        .map(|num| IceResult::from_owned(OwnedLiteral::LNegativeInteger(num)))
+                })
+                .or_else(|_| {
+                    text.parse::<f64>()
+                        .map(|num| IceResult::from_owned(OwnedLiteral::LFloat(num)))
+                })
+                .ok(),
+            (OwnedLiteral::LPositiveInteger(_), "number") => Some(IceResult::from_borrowed(self)),
+            (OwnedLiteral::LNegativeInteger(_), "number") => Some(IceResult::from_borrowed(self)),
+            (OwnedLiteral::LFloat(_), "number") => Some(IceResult::from_borrowed(self)),
+            (_, _) => panic!("Unimplemented cast"),
+        }
     }
 }