Merge pull request #3345 from cavanaug/master

Support context in line ranges

CHANGELOG.md

@@ -5,6 +5,7 @@
 
 - Add paging to `--list-themes`, see PR #3239 (@einfachIrgendwer0815)
 - Support negative relative line ranges, e.g. `bat -r :-10` / `bat -r='-10:'`, see #3068 (@ajesipow)
+- Support context in line ranges, e.g. `bat -r 30::5` /  `bat -r 30:40:5`, see #3345 (@cavanaug)
 
 ## Bugfixes
 

doc/long-help.txt

@@ -194,6 +194,8 @@ Options:
             '--line-range 40:' prints lines 40 to the end of the file
             '--line-range 40' only prints line 40
             '--line-range 30:+10' prints lines 30 to 40
+            '--line-range 35::5' prints lines 30 to 40 (line 35 with 5 lines of context)
+            '--line-range 30:40:2' prints lines 28 to 42 (range 30-40 with 2 lines of context)
 
   -L, --list-languages
           Display a list of supported languages for syntax highlighting.

src/bin/bat/clap_app.rs

@@ -525,7 +525,9 @@ pub fn build_app(interactive_output: bool) -> Command {
                      '--line-range :40' prints lines 1 to 40\n  \
                      '--line-range 40:' prints lines 40 to the end of the file\n  \
                      '--line-range 40' only prints line 40\n  \
-                     '--line-range 30:+10' prints lines 30 to 40",
+                     '--line-range 30:+10' prints lines 30 to 40\n  \
+                     '--line-range 35::5' prints lines 30 to 40 (line 35 with 5 lines of context)\n  \
+                     '--line-range 30:40:2' prints lines 28 to 42 (range 30-40 with 2 lines of context)",
                 ),
         )
         .arg(

src/line_range.rs

@@ -98,8 +98,33 @@ impl LineRange {
                 new_range.upper = RangeBound::Absolute(upper_absolute_bound);
                 Ok(new_range)
             }
+            3 => {
+                // Handle context syntax: N::C or N:M:C
+                if line_numbers[1].is_empty() {
+                    // Format: N::C - single line with context
+                    let line_number: usize = line_numbers[0].parse()
+                        .map_err(|_| "Invalid line number in N::C format")?;
+                    let context: usize = line_numbers[2].parse()
+                        .map_err(|_| "Invalid context number in N::C format")?;
+
+                    new_range.lower = RangeBound::Absolute(line_number.saturating_sub(context));
+                    new_range.upper = RangeBound::Absolute(line_number.saturating_add(context));
+                } else {
+                    // Format: N:M:C - range with context
+                    let start_line: usize = line_numbers[0].parse()
+                        .map_err(|_| "Invalid start line number in N:M:C format")?;
+                    let end_line: usize = line_numbers[1].parse()
+                        .map_err(|_| "Invalid end line number in N:M:C format")?;
+                    let context: usize = line_numbers[2].parse()
+                        .map_err(|_| "Invalid context number in N:M:C format")?;
+
+                    new_range.lower = RangeBound::Absolute(start_line.saturating_sub(context));
+                    new_range.upper = RangeBound::Absolute(end_line.saturating_add(context));
+                }
+                Ok(new_range)
+            }
             _ => Err(
-                "Line range contained more than one ':' character. Expected format: 'N' or 'N:M'"
+                "Line range contained too many ':' characters. Expected format: 'N', 'N:M', 'N::C', or 'N:M:C'"
                     .into(),
             ),
         }
@@ -210,14 +235,17 @@ fn test_parse_single() {
 
 #[test]
 fn test_parse_fail() {
-    let range = LineRange::from("40:50:80");
+    // Test 4+ colon parts should still fail
-    assert!(range.is_err());
+    let range = LineRange::from("40:50:80:90");
-    let range = LineRange::from("40::80");
     assert!(range.is_err());
+    // Test invalid formats that should still fail
     let range = LineRange::from("-2:5");
     assert!(range.is_err());
     let range = LineRange::from(":40:");
     assert!(range.is_err());
+    // Test completely malformed input
+    let range = LineRange::from("abc:def");
+    assert!(range.is_err());
 }
 
 #[test]
@@ -274,6 +302,57 @@ fn test_parse_minus_fail() {
     assert!(range.is_err());
 }
 
+#[test]
+fn test_parse_context_single_line() {
+    let range = LineRange::from("35::5").expect("Shouldn't fail on test!");
+    assert_eq!(RangeBound::Absolute(30), range.lower);
+    assert_eq!(RangeBound::Absolute(40), range.upper);
+}
+
+#[test]
+fn test_parse_context_range() {
+    let range = LineRange::from("30:40:2").expect("Shouldn't fail on test!");
+    assert_eq!(RangeBound::Absolute(28), range.lower);
+    assert_eq!(RangeBound::Absolute(42), range.upper);
+
+    // Test the case that used to fail but should now work
+    let range = LineRange::from("40:50:80").expect("Shouldn't fail on test!");
+    assert_eq!(RangeBound::Absolute(0), range.lower); // 40 - 80 = 0 (saturated)
+    assert_eq!(RangeBound::Absolute(130), range.upper); // 50 + 80 = 130
+}
+
+#[test]
+fn test_parse_context_edge_cases() {
+    // Test with small line numbers that would underflow
+    let range = LineRange::from("5::10").expect("Shouldn't fail on test!");
+    assert_eq!(RangeBound::Absolute(0), range.lower);
+    assert_eq!(RangeBound::Absolute(15), range.upper);
+
+    // Test with zero context
+    let range = LineRange::from("50::0").expect("Shouldn't fail on test!");
+    assert_eq!(RangeBound::Absolute(50), range.lower);
+    assert_eq!(RangeBound::Absolute(50), range.upper);
+
+    // Test range with zero context
+    let range = LineRange::from("30:40:0").expect("Shouldn't fail on test!");
+    assert_eq!(RangeBound::Absolute(30), range.lower);
+    assert_eq!(RangeBound::Absolute(40), range.upper);
+}
+
+#[test]
+fn test_parse_context_fail() {
+    let range = LineRange::from("40::z");
+    assert!(range.is_err());
+    let range = LineRange::from("::5");
+    assert!(range.is_err());
+    let range = LineRange::from("40::");
+    assert!(range.is_err());
+    let range = LineRange::from("30:40:z");
+    assert!(range.is_err());
+    let range = LineRange::from("30::40:5");
+    assert!(range.is_err());
+}
+
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum RangeCheckResult {
     // Within one of the given ranges

tests/examples/multiline.txt

@@ -2,3 +2,9 @@ line 1
 line 2
 line 3
 line 4
+line 5
+line 6
+line 7
+line 8
+line 9
+line 10

tests/integration_tests.rs

@@ -163,7 +163,7 @@ fn line_numbers() {
         .arg("--decorations=always")
         .assert()
         .success()
-        .stdout("   1 line 1\n   2 line 2\n   3 line 3\n   4 line 4\n");
+        .stdout("   1 line 1\n   2 line 2\n   3 line 3\n   4 line 4\n   5 line 5\n   6 line 6\n   7 line 7\n   8 line 8\n   9 line 9\n  10 line 10\n");
 }
 
 #[test]
@@ -183,7 +183,7 @@ fn line_range_up_to_2_from_back() {
         .arg("--line-range=:-2")
         .assert()
         .success()
-        .stdout("line 1\nline 2\n");
+        .stdout("line 1\nline 2\nline 3\nline 4\nline 5\nline 6\nline 7\nline 8\n");
 }
 
 #[test]
@@ -203,7 +203,7 @@ fn line_range_from_back_last_two() {
         .arg("--line-range=-2:")
         .assert()
         .success()
-        .stdout("line 3\nline 4\n");
+        .stdout("line 9\nline 10\n");
 }
 
 #[test]
@@ -230,10 +230,10 @@ fn line_range_first_two() {
 fn line_range_last_3() {
     bat()
         .arg("multiline.txt")
-        .arg("--line-range=2:")
+        .arg("--line-range=8:")
         .assert()
         .success()
-        .stdout("line 2\nline 3\nline 4\n");
+        .stdout("line 8\nline 9\nline 10\n");
 }
 
 #[test]
@@ -247,6 +247,137 @@ fn line_range_multiple() {
         .stdout("line 1\nline 2\nline 4\n");
 }
 
+#[test]
+fn line_range_multiple_with_context() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=2::1")
+        .arg("--line-range=8::1")
+        .assert()
+        .success()
+        .stdout("line 1\nline 2\nline 3\nline 7\nline 8\nline 9\n");
+}
+
+#[test]
+fn line_range_context_around_single_line() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=5::2")
+        .assert()
+        .success()
+        .stdout("line 3\nline 4\nline 5\nline 6\nline 7\n");
+}
+
+#[test]
+fn line_range_context_around_single_line_minimal() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=5::1")
+        .assert()
+        .success()
+        .stdout("line 4\nline 5\nline 6\n");
+}
+
+#[test]
+fn line_range_context_around_range() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=4:6:2")
+        .assert()
+        .success()
+        .stdout("line 2\nline 3\nline 4\nline 5\nline 6\nline 7\nline 8\n");
+}
+
+#[test]
+fn line_range_context_at_file_boundaries() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=1::2")
+        .assert()
+        .success()
+        .stdout("line 1\nline 2\nline 3\n");
+}
+
+#[test]
+fn line_range_context_at_end_of_file() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=10::2")
+        .assert()
+        .success()
+        .stdout("line 8\nline 9\nline 10\n");
+}
+
+#[test]
+fn line_range_context_zero() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=5::0")
+        .assert()
+        .success()
+        .stdout("line 5\n");
+}
+
+#[test]
+fn line_range_context_negative_single_line() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=5::-1")
+        .assert()
+        .failure()
+        .stderr(predicate::str::contains(
+            "Invalid context number in N::C format",
+        ));
+}
+
+#[test]
+fn line_range_context_negative_range() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=5:6:-1")
+        .assert()
+        .failure()
+        .stderr(predicate::str::contains(
+            "Invalid context number in N:M:C format",
+        ));
+}
+
+#[test]
+fn line_range_context_non_numeric_single_line() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=10::abc")
+        .assert()
+        .failure()
+        .stderr(predicate::str::contains(
+            "Invalid context number in N::C format",
+        ));
+}
+
+#[test]
+fn line_range_context_non_numeric_range() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=10:12:xyz")
+        .assert()
+        .failure()
+        .stderr(predicate::str::contains(
+            "Invalid context number in N:M:C format",
+        ));
+}
+
+#[test]
+fn line_range_context_very_large() {
+    bat()
+        .arg("multiline.txt")
+        .arg("--line-range=10::999999")
+        .assert()
+        .success()
+        .stdout(
+            "line 1\nline 2\nline 3\nline 4\nline 5\nline 6\nline 7\nline 8\nline 9\nline 10\n",
+        );
+}
+
 #[test]
 fn squeeze_blank() {
     bat()
@@ -1523,6 +1654,12 @@ fn snip() {
    2 line 2
  ...─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ 8< ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─
    4 line 4
+   5 line 5
+   6 line 6
+   7 line 7
+   8 line 8
+   9 line 9
+  10 line 10
 ",
         );
 }