Change DialectFunction to take &mut DialectInterpreter

- Update DialectFunction trait to use &mut DialectInterpreter
- Update function signature in BTreeMap to use &mut
- Update evaluate() and execute() methods to take &mut self
- Update all test function implementations
- Make interpreter variables mutable in tests

This allows functions to modify interpreter state (caching,
connections, etc.) which will be needed for IDE functions
that maintain state or connections to external services.

Author: nikomatsakis

server/src/dialect.rs

@@ -6,7 +6,7 @@ use serde_json::Value;
 pub mod ambiguity;
 
 pub struct DialectInterpreter<U> {
-    functions: BTreeMap<String, fn(&DialectInterpreter<U>, Value) -> anyhow::Result<Value>>,
+    functions: BTreeMap<String, fn(&mut DialectInterpreter<U>, Value) -> anyhow::Result<Value>>,
     userdata: U,
 }
 
@@ -29,7 +29,7 @@ impl<U> DialectInterpreter<U> {
         self.functions.insert(type_name_lower, Self::execute::<F>);
     }
 
-    pub fn evaluate(&self, value: Value) -> anyhow::Result<Value> {
+    pub fn evaluate(&mut self, value: Value) -> anyhow::Result<Value> {
         match value {
             Value::Null | Value::Bool(_) | Value::Number(_) | Value::String(_) => Ok(value),
             Value::Array(values) => Ok(Value::Array(
@@ -82,7 +82,7 @@ impl<U> DialectInterpreter<U> {
         }
     }
 
-    fn execute<F>(&self, value: Value) -> anyhow::Result<Value>
+    fn execute<F>(&mut self, value: Value) -> anyhow::Result<Value>
     where
         F: DialectFunction<U>,
     {
@@ -102,7 +102,7 @@ impl<U> DialectInterpreter<U> {
 pub trait DialectFunction<U>: DeserializeOwned {
     type Output: Serialize;
 
-    fn execute(self, interpreter: &DialectInterpreter<U>) -> anyhow::Result<Self::Output>;
+    fn execute(self, interpreter: &mut DialectInterpreter<U>) -> anyhow::Result<Self::Output>;
 }
 
 #[cfg(test)]
@@ -119,7 +119,7 @@ mod tests {
     impl DialectFunction<()> for Uppercase {
         type Output = String;
 
-        fn execute(self, _interpreter: &DialectInterpreter<()>) -> anyhow::Result<Self::Output> {
+        fn execute(self, _interpreter: &mut DialectInterpreter<()>) -> anyhow::Result<Self::Output> {
             Ok(self.text.to_uppercase())
         }
     }
@@ -134,7 +134,7 @@ mod tests {
     impl DialectFunction<()> for Concat {
         type Output = String;
 
-        fn execute(self, _interpreter: &DialectInterpreter<()>) -> anyhow::Result<Self::Output> {
+        fn execute(self, _interpreter: &mut DialectInterpreter<()>) -> anyhow::Result<Self::Output> {
             Ok(format!("{}{}", self.left, self.right))
         }
     }
@@ -149,7 +149,7 @@ mod tests {
     impl DialectFunction<()> for Add {
         type Output = i32;
 
-        fn execute(self, _interpreter: &DialectInterpreter<()>) -> anyhow::Result<Self::Output> {
+        fn execute(self, _interpreter: &mut DialectInterpreter<()>) -> anyhow::Result<Self::Output> {
             Ok(self.a + self.b)
         }
     }
@@ -210,7 +210,7 @@ mod tests {
 
     #[test]
     fn test_literal_values() {
-        let interpreter = DialectInterpreter::new(());
+        let mut interpreter = DialectInterpreter::new(());
 
         // Test that literal values pass through unchanged
         assert_eq!(
@@ -248,7 +248,7 @@ mod tests {
 
     #[test]
     fn test_unknown_function_error() {
-        let interpreter = DialectInterpreter::new(());
+        let mut interpreter = DialectInterpreter::new(());
 
         let input = serde_json::json!({"unknown": {"arg": "value"}});
         let result = interpreter.evaluate(input);
@@ -262,7 +262,7 @@ mod tests {
 
     #[test]
     fn test_invalid_function_format() {
-        let interpreter = DialectInterpreter::new(());
+        let mut interpreter = DialectInterpreter::new(());
 
         // Multiple keys in object
         let input = serde_json::json!({"func1": {}, "func2": {}});
@@ -284,7 +284,7 @@ where
 {
     type Output = V;
 
-    fn execute(self, _interpreter: &DialectInterpreter<U>) -> anyhow::Result<Self::Output> {
+    fn execute(self, _interpreter: &mut DialectInterpreter<U>) -> anyhow::Result<Self::Output> {
         Ok(self)
     }
 }