Implement to json; Improve map display

src/abstract_tree/tool.rs

@@ -174,6 +174,14 @@ impl Tool {
                     Value::String("read".to_string()),
                     Value::String("Get a file's content.".to_string()),
                 ])?;
+                help_table.insert(vec![
+                    Value::String("from_json".to_string()),
+                    Value::String("Convert a JSON string to a value.".to_string()),
+                ])?;
+                help_table.insert(vec![
+                    Value::String("to_json".to_string()),
+                    Value::String("Convert a value to a JSON string.".to_string()),
+                ])?;
 
                 Value::Table(help_table)
             }
@@ -191,7 +199,14 @@ impl Tool {
 
                 serde_json::from_str(json_string)?
             }
-            Tool::ToJson => todo!(),
+            Tool::ToJson => {
+                Error::expect_tool_argument_amount("to_json", 1, values.len())?;
+
+                let value = &values[0];
+                let json_string = serde_json::to_string(value)?;
+
+                Value::String(json_string)
+            }
         };
 
         Ok(value)

src/value/mod.rs

@@ -413,10 +413,10 @@ impl Display for Value {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
             Value::String(string) => write!(f, "{string}"),
-            Value::Float(float) => write!(f, "{}", float),
+            Value::Float(float) => write!(f, "{float}"),
-            Value::Integer(int) => write!(f, "{}", int),
+            Value::Integer(int) => write!(f, "{int}"),
-            Value::Boolean(boolean) => write!(f, "{}", boolean),
+            Value::Boolean(boolean) => write!(f, "{boolean}"),
-            Value::Empty => write!(f, "()"),
+            Value::Empty => write!(f, "empty"),
             Value::List(list) => {
                 write!(f, "[")?;
                 for value in list {

src/value/variable_map.rs

@@ -139,7 +139,11 @@ impl Default for VariableMap {
 
 impl Display for VariableMap {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        Table::from(self).fmt(f)
+        write!(f, "{{\n")?;
+        for (key, value) in &self.variables {
+            write!(f, "  {key} = {value}\n")?;
+        }
+        write!(f, "}}")
     }
 }