fix: serialization of values into string

minisql/src/type_system.rs

@@ -17,6 +17,7 @@ pub type Uuid = u64;
 //       I would rather have non-nullable values by default,
 //       and something like an explicit Option type for nulls.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(try_from = "String", into = "String")]
 pub enum Value {
     Number(f64), // TODO: Can't put floats as keys in maps, since they don't implement Eq. What to
     // do?
@@ -24,6 +25,7 @@ pub enum Value {
 }
 
 #[derive(Debug, Ord, Eq, Clone, PartialOrd, PartialEq, Serialize, Deserialize)]
+#[serde(try_from = "String", into = "String")]
 pub enum IndexableValue {
     String(String),
     Int(u64),
@@ -113,10 +115,88 @@ impl Value {
     }
 }
 
+//  Own string serialization so enums can be used as keys in maps
+impl From<IndexableValue> for String {
+    fn from(value: IndexableValue) -> Self {
+        match value {
+            IndexableValue::String(s) => format!("String({s})"),
+            IndexableValue::Int(i) => format!("Int({i})"),
+            IndexableValue::Uuid(u) => format!("Uuid({u})"),
+        }
+    }
+}
+
+impl TryFrom<String> for IndexableValue {
+    type Error = String;
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        if !value.ends_with(')') {
+            return Err(format!("Invalid IndexableValue: {}", value));
+        }
+
+        if value.starts_with("String(") {
+            let s = value[7..value.len() - 1].to_string();
+            return Ok(Self::String(s));
+        }
+
+        if value.starts_with("Int(") {
+            let s = value[4..value.len() - 1].to_string();
+            let i = s
+                .parse::<u64>()
+                .map_err(|e| format!("Invalid Int: {}", e))?;
+            return Ok(Self::Int(i));
+        }
+
+        if value.starts_with("Uuid(") {
+            let s = value[5..value.len() - 1].to_string();
+            let u = s
+                .parse::<u64>()
+                .map_err(|e| format!("Invalid UUID: {}", e))?;
+            return Ok(Self::Uuid(u));
+        }
+
+        Err(format!("Invalid IndexableValue: {}", value))
+    }
+}
+
+impl From<Value> for String {
+    fn from(value: Value) -> Self {
+        match value {
+            Value::Number(n) => format!("Number({n})"),
+            Value::Indexable(i) => format!("Indexable({})", String::from(i)),
+        }
+    }
+}
+
+impl TryFrom<String> for Value {
+    type Error = String;
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        if !value.ends_with(')') {
+            return Err(format!("Invalid Value: {}", value));
+        }
+
+        if value.starts_with("Number(") {
+            let s = value[7..value.len() - 1].to_string();
+            let n = s
+                .parse::<f64>()
+                .map_err(|e| format!("Invalid Number: {}", e))?;
+            return Ok(Self::Number(n));
+        }
+
+        if value.starts_with("Indexable(") {
+            let s = value[10..value.len() - 1].to_string();
+            let i = IndexableValue::try_from(s)?;
+            return Ok(Self::Indexable(i));
+        }
+
+        Err(format!("Invalid Value: {}", value))
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::{IndexableValue, Value};
     use crate::error::TypeConversionError::UnknownType;
+    use crate::type_system::Value::{Indexable, Number};
 
     #[test]
     fn test_encode_number() {
@@ -213,4 +293,25 @@ mod tests {
             Err(UnknownType { oid: 2950, size: 8 })
         ))
     }
+
+    #[test]
+    fn test_value_stringification() {
+        let pairs = vec![
+            (Number(1.0), "Number(1)"),
+            (
+                Indexable(IndexableValue::String("hello".to_string())),
+                "Indexable(String(hello))",
+            ),
+            (Indexable(IndexableValue::Int(123)), "Indexable(Int(123))"),
+            (Indexable(IndexableValue::Uuid(123)), "Indexable(Uuid(123))"),
+        ];
+
+        for (value, string) in pairs {
+            let serialized = String::from(value.clone());
+            assert_eq!(serialized, string);
+
+            let deserialized = Value::try_from(serialized);
+            assert_eq!(deserialized, Ok(value));
+        }
+    }
 }