Add support for interval + operator

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2023 Amr Hesham
+Copyright (c) 2023 - 2025 Amr Hesham
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -113,7 +113,7 @@ SELECT path, count() AS changes_count, SUM(insertions) AS additions, SUM(removal
 ```
 MIT License
 
-Copyright (c) 2023 Amr Hesham
+Copyright (c) 2023 - 2025 Amr Hesham
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

crates/gitql-ast/src/interval.rs

@@ -10,6 +10,19 @@ pub struct Interval {
     pub seconds: f64,
 }
 
+impl Interval {
+    pub fn add(&self, interval: &Interval) -> Interval {
+        let mut result = self.clone();
+        result.years += interval.years;
+        result.months += interval.months;
+        result.days += interval.days;
+        result.hours += interval.hours;
+        result.minutes += interval.minutes;
+        result.seconds += interval.seconds;
+        result
+    }
+}
+
 impl fmt::Display for Interval {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut parts = Vec::new();

crates/gitql-ast/src/types/interval.rs

@@ -11,10 +11,18 @@ impl DataType for IntervalType {
     }
 
     fn equals(&self, other: &Box<dyn DataType>) -> bool {
-        other.is_any() || other.is_int() || other.is_variant_with(|t| t.is_interval())
+        other.is_any() || other.is_interval() || other.is_variant_with(|t| t.is_interval())
     }
 
     fn as_any(&self) -> &dyn Any {
         self
     }
+
+    fn can_perform_add_op_with(&self) -> Vec<Box<dyn DataType>> {
+        vec![Box::new(IntervalType)]
+    }
+
+    fn add_op_result_type(&self, _other: &Box<dyn DataType>) -> Box<dyn DataType> {
+        Box::new(IntervalType)
+    }
 }

crates/gitql-core/src/values/interval.rs

@@ -41,4 +41,12 @@ impl Value for IntervalValue {
     fn as_any(&self) -> &dyn Any {
         self
     }
+
+    fn add_op(&self, other: &Box<dyn Value>) -> Result<Box<dyn Value>, String> {
+        if let Some(other_interval) = other.as_any().downcast_ref::<IntervalValue>() {
+            let result = self.interval.add(&other_interval.interval);
+            return Ok(Box::new(IntervalValue::new(result)));
+        }
+        Err("Unexpected type to perform `+` with".to_string())
+    }
 }

crates/gitql-parser/src/parser.rs

@@ -3201,7 +3201,7 @@ fn parse_term_expression(
 
             // Return error if this operator can't be performed even with implicit cast
             return Err(Diagnostic::error(&format!(
-                "Operator `-` can't be performed between types `{}` and `{}`",
+                "Operator `+` can't be performed between types `{}` and `{}`",
                 lhs_type, rhs_type
             ))
             .add_help(