Merge pull request #1276 from tommilligan/style-rule

style: add component 'rule' for horizontal file delimiter

26 files changed, 499 insertions, 14 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 91a0ab46..ba6f7235 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 ## Features
 
 - Adjust pager configuration to comply with `--wrap=never`, see #1255 (@gahag)
+- Added a new `--style` value, `rule`, which adds a simple horizontal ruled line between files, see #1276 (@tommilligan)
 
 ## Bugfixes
 
diff --git a/assets/manual/bat.1.in b/assets/manual/bat.1.in
index a6846b5d..65a17fe1 100644
--- a/assets/manual/bat.1.in
+++ b/assets/manual/bat.1.in
@@ -129,7 +129,7 @@ Configure which elements (line numbers, file headers, grid borders, Git modifica
 of components to display (e.g. 'numbers,changes,grid') or a pre\-defined style ('full').
 To set a default style, add the '\-\-style=".."' option to the configuration file or
 export the BAT_STYLE environment variable (e.g.: export BAT_STYLE=".."). Possible
-values: *auto*, full, plain, changes, header, grid, numbers, snip.
+values: *auto*, full, plain, changes, header, grid, rule, numbers, snip.
 .HP
 \fB\-r\fR, \fB\-\-line\-range\fR <N:M>...
 .IP
diff --git a/src/bin/bat/app.rs b/src/bin/bat/app.rs
index 8249e3c9..8d09618c 100644
--- a/src/bin/bat/app.rs
+++ b/src/bin/bat/app.rs
@@ -288,8 +288,8 @@ impl App {
 
     fn style_components(&self) -> Result<StyleComponents> {
         let matches = &self.matches;
-        Ok(StyleComponents(
-            if matches.value_of("decorations") == Some("never") {
+        let mut styled_components =
+            StyleComponents(if matches.value_of("decorations") == Some("never") {
                 HashSet::new()
             } else if matches.is_present("number") {
                 [StyleComponent::LineNumbers].iter().cloned().collect()
@@ -323,7 +323,17 @@ impl App {
                         acc.extend(components.iter().cloned());
                         acc
                     })
-            },
-        ))
+            });
+
+        // If `grid` is set, remove `rule` as it is a subset of `grid`, and print a warning.
+        if styled_components.grid() && styled_components.0.remove(&StyleComponent::Rule) {
+            use ansi_term::Colour::Yellow;
+            eprintln!(
+                "{}: Style 'rule' is a subset of style 'grid', 'rule' will not be visible.",
+                Yellow.paint("[bat warning]"),
+            );
+        }
+
+        Ok(styled_components)
     }
 }
diff --git a/src/bin/bat/clap_app.rs b/src/bin/bat/clap_app.rs
index d04abd8a..4e642760 100644
--- a/src/bin/bat/clap_app.rs
+++ b/src/bin/bat/clap_app.rs
@@ -367,7 +367,7 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
                 .validator(|val| {
                     let mut invalid_vals = val.split(',').filter(|style| {
                         !&[
-                            "auto", "full", "plain", "header", "grid", "numbers", "snip",
+                            "auto", "full", "plain", "header", "grid", "rule", "numbers", "snip",
                             #[cfg(feature = "git")]
                                 "changes",
                         ]
@@ -382,7 +382,7 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
                 })
                 .help(
                     "Comma-separated list of style elements to display \
-                     (*auto*, full, plain, changes, header, grid, numbers, snip).",
+                     (*auto*, full, plain, changes, header, grid, rule, numbers, snip).",
                 )
                 .long_help(
                     "Configure which elements (line numbers, file headers, grid \
@@ -400,6 +400,7 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
                      * header: show filenames before the content.\n  \
                      * grid: vertical/horizontal lines to separate side bar\n          \
                        and the header from the content.\n  \
+                     * rule: horizontal lines to delimit files.\n  \
                      * numbers: show line numbers in the side bar.\n  \
                      * snip: draw separation lines between distinct line ranges.",
                 ),
diff --git a/src/pretty_printer.rs b/src/pretty_printer.rs
index c9530bf4..89745eec 100644
--- a/src/pretty_printer.rs
+++ b/src/pretty_printer.rs
@@ -23,6 +23,7 @@ struct ActiveStyleComponents {
     header: bool,
     vcs_modification_markers: bool,
     grid: bool,
+    rule: bool,
     line_numbers: bool,
     snip: bool,
 }
@@ -179,6 +180,12 @@ impl<'a> PrettyPrinter<'a> {
         self
     }
 
+    /// Whether to paint a horizontal rule to delimit files
+    pub fn rule(&mut self, yes: bool) -> &mut Self {
+        self.active_style_components.rule = yes;
+        self
+    }
+
     /// Whether to show modification markers for VCS changes. This has no effect if
     /// the `git` feature is not activated.
     #[cfg_attr(
@@ -285,6 +292,9 @@ impl<'a> PrettyPrinter<'a> {
         if self.active_style_components.grid {
             style_components.push(StyleComponent::Grid);
         }
+        if self.active_style_components.rule {
+            style_components.push(StyleComponent::Rule);
+        }
         if self.active_style_components.header {
             style_components.push(StyleComponent::Header);
         }
diff --git a/src/printer.rs b/src/printer.rs
index 71bf78ee..e0829874 100644
--- a/src/printer.rs
+++ b/src/printer.rs
@@ -200,13 +200,18 @@ impl<'a> InteractivePrinter<'a> {
         })
     }
 
+    fn print_horizontal_line_term(&mut self, handle: &mut dyn Write, style: Style) -> Result<()> {
+        writeln!(
+            handle,
+            "{}",
+            style.paint("─".repeat(self.config.term_width))
+        )?;
+        Ok(())
+    }
+
     fn print_horizontal_line(&mut self, handle: &mut dyn Write, grid_char: char) -> Result<()> {
         if self.panel_width == 0 {
-            writeln!(
-                handle,
-                "{}",
-                self.colors.grid.paint("─".repeat(self.config.term_width))
-            )?;
+            self.print_horizontal_line_term(handle, self.colors.grid)?;
         } else {
             let hline = "─".repeat(self.config.term_width - (self.panel_width + 1));
             let hline = format!("{}{}{}", "─".repeat(self.panel_width), grid_char, hline);
@@ -251,6 +256,10 @@ impl<'a> Printer for InteractivePrinter<'a> {
         input: &OpenedInput,
         add_header_padding: bool,
     ) -> Result<()> {
+        if add_header_padding && self.config.style_components.rule() {
+            self.print_horizontal_line_term(handle, self.colors.rule)?;
+        }
+
         if !self.config.style_components.header() {
             if Some(ContentType::BINARY) == self.content_type && !self.config.show_nonprintable {
                 writeln!(
@@ -279,7 +288,8 @@ impl<'a> Printer for InteractivePrinter<'a> {
                     .paint(if self.panel_width > 0 { "│ " } else { "" }),
             )?;
         } else {
-            if add_header_padding {
+            // Only pad space between files, if we haven't already drawn a horizontal rule
+            if add_header_padding && !self.config.style_components.rule() {
                 writeln!(handle)?;
             }
             write!(handle, "{}", " ".repeat(self.panel_width))?;
@@ -603,6 +613,7 @@ const DEFAULT_GUTTER_COLOR: u8 = 238;
 #[derive(Debug, Default)]
 pub struct Colors {
     pub grid: Style,
+    pub rule: Style,
     pub filename: Style,
     pub git_added: Style,
     pub git_removed: Style,
@@ -624,6 +635,7 @@ impl Colors {
 
         Colors {
             grid: gutter_color.normal(),
+            rule: gutter_color.normal(),
             filename: Style::new().bold(),
             git_added: Green.normal(),
             git_removed: Red.normal(),
diff --git a/src/style.rs b/src/style.rs
index 8d51cbde..65414206 100644
--- a/src/style.rs
+++ b/src/style.rs
@@ -9,6 +9,7 @@ pub enum StyleComponent {
     #[cfg(feature = "git")]
     Changes,
     Grid,
+    Rule,
     Header,
     LineNumbers,
     Snip,
@@ -29,6 +30,7 @@ impl StyleComponent {
             #[cfg(feature = "git")]
             StyleComponent::Changes => &[StyleComponent::Changes],
             StyleComponent::Grid => &[StyleComponent::Grid],
+            StyleComponent::Rule => &[StyleComponent::Rule],
             StyleComponent::Header => &[StyleComponent::Header],
             StyleComponent::LineNumbers => &[StyleComponent::LineNumbers],
             StyleComponent::Snip => &[StyleComponent::Snip],
@@ -54,6 +56,7 @@ impl FromStr for StyleComponent {
             #[cfg(feature = "git")]
             "changes" => Ok(StyleComponent::Changes),
             "grid" => Ok(StyleComponent::Grid),
+            "rule" => Ok(StyleComponent::Rule),
             "header" => Ok(StyleComponent::Header),
             "numbers" => Ok(StyleComponent::LineNumbers),
             "snip" => Ok(StyleComponent::Snip),
@@ -81,6 +84,10 @@ impl StyleComponents {
         self.0.contains(&StyleComponent::Grid)
     }
 
+    pub fn rule(&self) -> bool {
+        self.0.contains(&StyleComponent::Rule)
+    }
+
     pub fn header(&self) -> bool {
         self.0.contains(&StyleComponent::Header)
     }
diff --git a/tests/integration_tests.rs b/tests/integration_tests.rs
index 09ac8498..ac11efb4 100644
--- a/tests/integration_tests.rs
+++ b/tests/integration_tests.rs
@@ -581,6 +581,18 @@ fn empty_file_leads_to_empty_output_with_grid_enabled() {
 }
 
 #[test]
+fn empty_file_leads_to_empty_output_with_rule_enabled() {
+    bat()
+        .arg("empty.txt")
+        .arg("--style=rule")
+        .arg("--decorations=always")
+        .arg("--terminal-width=80")
+        .assert()
+        .success()
+        .stdout("");
+}
+
+#[test]
 fn filename_basic() {
     bat()
         .arg("test.txt")
@@ -678,6 +690,48 @@ fn header_padding() {
         .stderr("");
 }
 
+#[test]
+fn header_padding_rule() {
+    bat()
+        .arg("--decorations=always")
+        .arg("--style=header,rule")
+        .arg("--terminal-width=80")
+        .arg("test.txt")
+        .arg("single-line.txt")
+        .assert()
+        .stdout(
+            "File: test.txt
+hello world
+────────────────────────────────────────────────────────────────────────────────
+File: single-line.txt
+Single Line
+",
+        )
+        .stderr("");
+}
+
+#[test]
+fn grid_overrides_rule() {
+    bat()
+        .arg("--decorations=always")
+        .arg("--style=grid,rule")
+        .arg("--terminal-width=80")
+        .arg("test.txt")
+        .arg("single-line.txt")
+        .assert()
+        .stdout(
+            "\
+────────────────────────────────────────────────────────────────────────────────
+hello world
+────────────────────────────────────────────────────────────────────────────────
+────────────────────────────────────────────────────────────────────────────────
+Single Line
+────────────────────────────────────────────────────────────────────────────────
+",
+        )
+        .stderr("\x1b[33m[bat warning]\x1b[0m: Style 'rule' is a subset of style 'grid', 'rule' will not be visible.\n");
+}
+
 #[cfg(target_os = "linux")]
 #[test]
 fn file_with_invalid_utf8_filename() {
diff --git a/tests/snapshot_tests.rs b/tests/snapshot_tests.rs
index ad41edb2..8abb8414 100644
--- a/tests/snapshot_tests.rs
+++ b/tests/snapshot_tests.rs
@@ -19,17 +19,27 @@ snapshot_tests! {
     grid:                        "grid",
     header:                      "header",
     numbers:                     "numbers",
+    rule:                        "rule",
     changes_grid:                "changes,grid",
     changes_header:              "changes,header",
     changes_numbers:             "changes,numbers",
+    changes_rule:                "changes,rule",
     grid_header:                 "grid,header",
     grid_numbers:                "grid,numbers",
+    grid_rule:                   "grid,rule",
     header_numbers:              "header,numbers",
+    header_rule:                 "header,rule",
     changes_grid_header:         "changes,grid,header",
     changes_grid_numbers:        "changes,grid,numbers",
+    changes_grid_rule:           "changes,grid,rule",
     changes_header_numbers:      "changes,header,numbers",
+    changes_header_rule:         "changes,header,rule",
     grid_header_numbers:         "grid,header,numbers",
+    grid_header_rule:            "grid,header,rule",
+    header_numbers_rule:         "header,numbers,rule",
     changes_grid_header_numbers: "changes,grid,header,numbers",
+    changes_grid_header_rule:    "changes,grid,header,rule",
+    changes_grid_header_numbers_rule: "changes,grid,header,numbers,rule",
     full:                        "full",
     plain:                       "plain",
 }
diff --git a/tests/snapshots/generate_snapshots.py b/tests/snapshots/generate_snapshots.py
index fd17b285..bb7d69ba 100755
--- a/tests/snapshots/generate_snapshots.py
+++ b/tests/snapshots/generate_snapshots.py
@@ -7,7 +7,7 @@ import shutil
 
 
 def generate_snapshots():
-    single_styles = ["changes", "grid", "header", "numbers"]
+    single_styles = ["changes", "grid", "header", "numbers", "rule"]
     collective_styles = ["full", "plain"]
 
     for num in range(len(single_styles)):
diff --git a/tests/snapshots/output/changes_grid_header_numbers_rule.snapshot.txt b/tests/snapshots/output/changes_grid_header_numbers_rule.snapshot.txt
new file mode 100644
index 00000000..cee4737f
--- /dev/null
+++ b/tests/snapshots/output/changes_grid_header_numbers_rule.snapshot.txt
@@ -0,0 +1,26 @@
+───────┬────────────────────────────────────────────────────────────────────────
+       │ File: sample.rs
+───────┼────────────────────────────────────────────────────────────────────────
+   1   │ struct Rectangle {
+   2   │     width: u32,
+   3   │     height: u32,
+   4   │ }
+   5   │ 
+   6 _ │ fn main() {
+   7   │     let rect1 = Rectangle { width: 30, height: 50 };
+   8   │ 
+   9   │     println!(
+  10 ~ │         "The perimeter of the rectangle is {} pixels.",
+  11 ~ │         perimeter(&rect1)
+  12   │     );
+  13 + │     println!(r#"This line contains invalid utf8:  "�����"#;
+  14   │ }
+  15   │ 
+  16   │ fn area(rectangle: &Rectangle) -> u32 {
+  17   │     rectangle.width * rectangle.height
+  18   │ }
+  19 + │ 
+  20 + │ fn perimeter(rectangle: &Rectangle) -> u32 {
+  21 + │     (rectangle.width + rectangle.height) * 2
+  22 + │ }
+───────┴────────────────────────────────────────────────────────────────────────
diff --git a/tests/snapshots/output/changes_grid_header_rule.snapshot.txt b/tests/snapshots/output/changes_grid_header_rule.snapshot.txt
new file mode 100644
index 00000000..655b6e24
--- /dev/null
+++ b/tests/snapshots/output/changes_grid_header_rule.snapshot.txt
@@ -0,0 +1,26 @@
+──┬─────────────────────────────────────────────────────────────────────────────
+  │ File: sample.rs
+──┼─────────────────────────────────────────────────────────────────────────────
+  │ struct Rectangle {
+  │     width: u32,
+  │     height: u32,
+  │ }
+  │ 
+_ │ fn main() {
+  │     let rect1 = Rectangle { width: 30, height: 50 };
+  │ 
+  │     println!(
+~ │         "The perimeter of the rectangle is {} pixels.",
+~ │         perimeter(&rect1)
+  │     );
++ │     println!(r#"This line contains invalid utf8:  "�����"#;
+  │ }
+  │ 
+  │ fn area(rectangle: &Rectangle) -> u32 {
+  │     rectangle.width * rectangle.height
+  │ }
++ │ 
++ │ fn perimeter(rectangle: &Rectangle) -> u32 {
++ │     (rectangle.width + rectangle.height) * 2
++ │ }
+──┴─────────────────────────────────────────────────────────────────────────────
diff --git a/tests/snapshots/output/changes_grid_numbers_rule.snapshot.txt b/tests/snapshots/output/changes_grid_numbers_rule.snapshot.txt
new file mode 100644
index 00000000..7fe7cccf
--- /dev/null
+++ b/tests/snapshots/output/changes_grid_numbers_rule.snapshot.txt
@@ -0,0 +1,24 @@
+───────┬────────────────────────────────────────────────────────────────────────
+   1   │ struct Rectangle {
+   2   │     width: u32,
+   3   │     height: u32,
+   4   │ }
+   5   │ 
+   6 _ │ fn main() {
+   7   │     let rect1 = Rectangle { width: 30, height: 50 };
+   8   │ 
+   9   │     println!(
+  10 ~ │         "The perimeter of the rectangle is {} pixels.",
+  11 ~ │         perimeter(&rect1)
+  12   │     );
+  13 + │     println!(r#"This line contains invalid utf8:  "�����"#;
+  14   │ }
+  15   │ 
+  16   │ fn area(rectangle: &Rectangle) -> u32 {
+  17   │     rectangle.width * rectangle.height
+  18   │ }
+  19 + │ 
+  20 + │ fn perimeter(rectangle: &Rectangle) -> u32 {
+  21 + │     (rectangle.width + rectangle.height) * 2
+  22 + │ }
+───────┴────────────────────────────────────────────────────────────────────────
diff --git a/tests/snapshots/output/changes_grid_rule.snapshot.txt b/tests/snapshots/output/changes_grid_rule.snapshot.txt
new file mode 100644
index 00000000..04767b8b
--- /dev/null
+++ b/tests/snapshots/output/changes_grid_rule.snapshot.txt
@@ -0,0 +1,24 @@
+──┬─────────────────────────────────────────────────────────────────────────────
+  │ struct Rectangle {
+  │     width: u32,
+  │     height: u32,
+  │ }
+  │ 
+_ │ fn main() {
+  │     let rect1 = Rectangle { width: 30, height: 50 };
+  │ 
+  │     println!(
+~ │         "The perimeter of the rectangle is {} pixels.",
+~ │         perimeter(&rect1)
+  │     );
++ │     println!(r#"This line contains invalid utf8:  "�����"#;
+  │ }
+  │ 
+  │ fn area(rectangle: &Rectangle) -> u32 {
+  │     rectangle.width * rectangle.height
+  │ }
++ │ 
++ │ fn perimeter(rectangle: &Rectangle) -> u32 {
++ │     (rectangle.width + rectangle.height) * 2
++ │ }
+──┴─────────────────────────────────────────────────────────────────────────────
diff --git a/tests/snapshots/output/changes_header_numbers_rule.snapshot.txt b/tests/snapshots/output/changes_header_numbers_rule.snapshot.txt
new file mode 100644
index 00000000..77145eb9
--- /dev/null
+++ b/tests/snapshots/output/changes_header_numbers_rule.snapshot.txt
@@ -0,0 +1,23 @@
+       File: sample.rs
+   1   struct Rectangle {
+   2       width: u32,
+   3       height: u32,
+   4   }
+   5   
+   6 _ fn main() {
+   7       let rect1 = Rectangle { width: 30, height: 50 };
+   8   
+   9       println!(
+  10 ~         "The perimeter of the rectangle is {} pixels.",
+  11 ~         perimeter(&rect1)
+  12       );
+  13 +     println!(r#"This line contains invalid utf8:  "�����"#;
+  14   }
+  15   
+  16   fn area(rectangle: &Rectangle) -> u32 {
+  17       rectangle.width * rectangle.height
+  18   }
+  19 + 
+  20 + fn perimeter(rectangle: &Rectangle) -> u32 {
+  21 +     (rectangle.width + rectangle.height) * 2
+  22 + }
diff --git a/tests/snapshots/output/changes_header_rule.snapshot.txt b/tests/snapshots/output/changes_header_rule.snapshot.txt
new file mode 100644
index 00000000..82fe8c47
--- /dev/null
+++ b/tests/snapshots/output/changes_header_rule.snapshot.txt
@@ -0,0 +1,23 @@
+  File: sample.rs
+  struct Rectangle {
+      width: u32,
+      height: u32,
+  }
+  
+_ fn main() {
+      let rect1 = Rectangle { width: 30, height: 50 };
+  
+      println!(
+~         "The perimeter of the rectangle is {} pixels.",
+~         perimeter(&rect1)
+      );
++     println!(r#"This line contains invalid utf8:  "�����"#;
+  }
+  
+  fn area(rectangle: &Rectangle) -> u32 {
+      rectangle.width * rectangle.height
+  }
++ 
++ fn perimeter(rectangle: &Rectangle) -> u32 {
++     (rectangle.width + rectangle.height) * 2
++ }
diff --git a/tests/snapshots/output/changes_numbers_rule.snapshot.txt b/tests/snapshots/output/changes_numbers_rule.snapshot.txt
new file mode 100644
index 00000000..bdfe745b
--- /dev/null
+++ b/tests/snapshots/output/changes_numbers_rule.snapshot.txt
@@ -0,0 +1,22 @@
+   1   struct Rectangle {
+   2       width: u32,
+   3       height: u32,
+   4   }
+   5   
+   6 _ fn main() {
+   7       let rect1 = Rectangle { width: 30, height: 50 };
+   8   
+   9       println!(
+  10 ~         "The perimeter of the rectangle is {} pixels.",
+  11 ~         perimeter(&rect1)
+  12       );
+  13 +     println!(r#"This line contains invalid utf8:  "�����"#;
+  14   }
+  15   
+  16   fn area(rectangle: &Rectangle) -> u32 {
+  17       rectangle.width * rectangle.height
+  18   }
+  19 + 
+  20 + fn perimeter(rectangle: &Rectangle) -> u32 {
+  21 +     (rectangle.width + rectangle.height) * 2
+  22 + }
diff --git a/tests/snapshots/output/changes_rule.snapshot.txt b/tests/snapshots/output/changes_rule.snapshot.txt
new file mode 100644
index 00000000..28d87201
--- /dev/null
+++ b/tests/snapshots/output/changes_rule.snapshot.txt
@@ -0,0 +1,22 @@
+  struct Rectangle {
+      width: u32,
+      height: u32,
+  }
+  
+_ fn main() {
+      let rect1 = Rectangle { width: 30, height: 50 };
+  
+      println!(
+~         "The perimeter of the rectangle is {} pixels.",
+~         perimeter(&rect1)
+      );
++     println!(r#"This line contains invalid utf8:  "�����"#;
+  }
+  
+  fn area(rectangle: &Rectangle) -> u32 {
+      rectangle.width * rectangle.height
+  }
++ 
++ fn perimeter(rectangle: &Rectangle) -> u32 {
++     (rectangle.width + rectangle.height) * 2
++ }
diff --git a/tests/snapshots/output/grid_header_numbers_rule.snapshot.txt b/tests/snapshots/output/grid_header_numbers_rule.snapshot.txt
new file mode 100644
index 00000000..e9f1a9cf
--- /dev/null
+++ b/tests/snapshots/output/grid_header_numbers_rule.snapshot.txt
@@ -0,0 +1,26 @@
+─────┬──────────────────────────────────────────────────────────────────────────
+     │ File: sample.rs
+─────┼──────────────────────────────────────────────────────────────────────────
+   1 │ struct Rectangle {
+   2 │     width: u32,
+   3 │     height: u32,
+   4 │ }
+   5 │ 
+   6 │ fn main() {
+   7 │     let rect1 = Rectangle { width: 30, height: 50 };
+   8 │ 
+   9 │     println!(
+  10 │         "The perimeter of the rectangle is {} pixels.",
+  11 │         perimeter(&rect1)
+  12 │     );
+  13 │     println!(r#"This line contains invalid utf8:  "�����"#;
+  14 │ }
+  15 │ 
+  16 │ fn area(rectangle: &Rectangle) -> u32 {
+  17 │     rectangle.width * rectangle.height
+  18 │ }
+  19 │ 
+  20 │ fn perimeter(rectangle: &Rectangle) -> u32 {
+  21 │     (rectangle.width + rectangle.height) * 2
+  22 │ }
+─────┴──────────────────────────────────────────────────────────────────────────
diff --git a/tests/snapshots/output/grid_header_rule.snapshot.txt b/tests/snapshots/output/grid_header_rule.snapshot.txt
new file mode 100644
index 00000000..50c16941
--- /dev/null
+++ b/tests/snapshots/output/grid_header_rule.snapshot.txt
@@ -0,0 +1,26 @@
+────────────────────────────────────────────────────────────────────────────────
+File: sample.rs
+────────────────────────────────────────────────────────────────────────────────
+struct Rectangle {
+    width: u32,
+    height: u32,
+}
+
+fn main() {
+    let rect1 = Rectangle { width: 30, height: 50 };
+
+    println!(
+        "The perimeter of the rectangle is {} pixels.",
+        perimeter(&rect1)
+    );
+    println!(r#"This line contains invalid utf8:  "�����"#;
+}
+
+fn area(rectangle: &Rectangle) -> u32 {
+    rectangle.width * rectangle.height
+}
+
+fn perimeter(rectangle: &Rectangle) -> u32 {
+    (rectangle.width + rectangle.height) * 2
+}
+────────────────────────────────────────────────────────────────────────────────
diff --git a/tests/snapshots/output/grid_numbers_rule.snapshot.txt b/tests/snapshots/output/grid_numbers_rule.snapshot.txt
new file mode 100644
index 00000000..09614667
--- /dev/null
+++ b/tests/snapshots/output/grid_numbers_rule.snapshot.txt
@@ -0,0 +1,24 @@
+─────┬──────────────────────────────────────────────────────────────────────────
+   1 │ struct Rectangle {
+   2 │     width: u32,
+   3 │     height: u32,
+   4 │ }
+   5 │ 
+   6 │ fn main() {
+   7 │     let rect1 = Rectangle { width: 30, height: 50 };
+   8 │ 
+   9 │     println!(
+  10 │         "The perimeter of the rectangle is {} pixels.",
+  11 │         perimeter(&rect1)
+  12 │     );
+  13 │     println!(r#"This line contains invalid utf8:  "�����"#;
+  14 │ }
+  15 │ 
+  16 │ fn area(rectangle: &Rectangle) -> u32 {
+  17 │     rectangle.width * rectangle.height
+  18 │ }
+  19 │ 
+  20 │ fn perimeter(rectangle: &Rectangle) -> u32 {
+  21 │     (rectangle.width + rectangle.height) * 2
+  22 │ }
+─────┴──────────────────────────────────────────────────────────────────────────
diff --git a/tests/snapshots/output/grid_rule.snapshot.txt b/tests/snapshots/output/grid_rule.snapshot.txt
new file mode 100644
index 00000000..5b970581
--- /dev/null
+++ b/tests/snapshots/output/grid_rule.snapshot.txt
@@ -0,0 +1,24 @@
+────────────────────────────────────────────────────────────────────────────────
+struct Rectangle {
+    width: u32,
+    height: u32,
+}
+
+fn main() {
+    let rect1 = Rectangle { width: 30, height: 50 };
+
+    println!(
+        "The peri