refactor: implement Display for EvalStmt

Cargo.toml

@@ -26,6 +26,7 @@ categories = ["parser-implementations"]
 
 [dependencies]
 cfgrammar = "0.13.5"
+chrono = "0.4.38"
 lazy_static = "1.4.0"
 lrlex = "0.13.5"
 lrpar = "0.13.5"

src/parser/ast.rs

@@ -20,6 +20,7 @@ use crate::parser::token::{Token, TokenId, TokenType};
 use crate::parser::value::ValueType;
 use crate::parser::{indent, Function, FunctionArgs, Prettier, MAX_CHARACTERS_PER_LINE};
 use crate::util::display_duration;
+use chrono::{DateTime, Utc};
 use std::fmt::{self, Write};
 use std::ops::Neg;
 use std::sync::Arc;
@@ -35,9 +36,10 @@ use std::time::{Duration, SystemTime};
 /// # Vector Match Modifier
 ///
 /// - Exclude means `without` removes the listed labels from the result vector,
-/// while all other labels are preserved in the output.
+///   while all other labels are preserved in the output.
+///
 /// - Include means `by` does the opposite and drops labels that are not listed in the by clause,
-/// even if their label values are identical between all elements of the vector.
+///   even if their label values are identical between all elements of the vector.
 ///
 /// if empty listed labels, meaning no grouping
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -315,6 +317,20 @@ pub struct EvalStmt {
     pub lookback_delta: Duration,
 }
 
+impl fmt::Display for EvalStmt {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "[{}] @ [{}, {}, {}, {}]",
+            self.expr,
+            DateTime::<Utc>::from(self.start).to_rfc3339(),
+            DateTime::<Utc>::from(self.end).to_rfc3339(),
+            display_duration(&self.interval),
+            display_duration(&self.lookback_delta)
+        )
+    }
+}
+
 /// Grammar:
 /// ``` norust
 /// <aggr-op> [without|by (<label list>)] ([parameter,] <vector expression>)
@@ -2440,4 +2456,28 @@ or
             assert_eq!(expect, crate::parser::parse(input).unwrap().prettify());
         }
     }
+
+    #[test]
+    fn test_eval_stmt_to_string() {
+        let query = r#"http_requests_total{job="apiserver", handler="/api/comments"}[5m]"#;
+        let start = "2024-10-08T07:15:00.022978+00:00";
+        let end = "2024-10-08T07:15:30.012978+00:00";
+        let expect = r#"[http_requests_total{handler="/api/comments",job="apiserver"}[5m]] @ [2024-10-08T07:15:00.022978+00:00, 2024-10-08T07:15:30.012978+00:00, 1m, 5m]"#;
+
+        let stmt = EvalStmt {
+            expr: crate::parser::parse(query).unwrap(),
+            start: DateTime::parse_from_rfc3339(start)
+                .unwrap()
+                .with_timezone(&Utc)
+                .into(),
+            end: DateTime::parse_from_rfc3339(end)
+                .unwrap()
+                .with_timezone(&Utc)
+                .into(),
+            interval: Duration::from_secs(60),
+            lookback_delta: Duration::from_secs(300),
+        };
+
+        assert_eq!(expect, stmt.to_string());
+    }
 }