Navigate regexp (#782)

* Allow navigate-regexp value to be overridden.

* Don't add an empty label to the navigate_regexp.

* Make --hunk-label=str not require --navigate.

* Change navigate regexp to navigate regex.

* Turn navigate-regex into an Option<String>.

8 files changed, 41 insertions, 23 deletions

diff --git a/README.md b/README.md
index 8a2aa1f4..1c4b8701 100644
--- a/README.md
+++ b/README.md
@@ -860,6 +860,9 @@ OPTIONS:
         --wrap-right-prefix-symbol <wrap-right-prefix-symbol>
             Symbol displayed in front of right-aligned wrapped content [default: …]
 
+        --navigate-regex <navigate-regex>
+            A regexp to use in the less pager when navigating (auto-generated when unspecified)
+
         --file-modified-label <file-modified-label>
             Text to display in front of a modified file path [default: ]
 
diff --git a/src/cli.rs b/src/cli.rs
index 9f4a18cf..bc928291 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -573,6 +573,10 @@ pub struct Opt {
     #[structopt(long = "wrap-right-prefix-symbol", default_value = "…")]
     pub wrap_right_prefix_symbol: String,
 
+    #[structopt(long = "navigate-regex")]
+    /// A regexp to use in the less pager when navigating (auto-generated when unspecified)
+    pub navigate_regex: Option<String>,
+
     #[structopt(long = "file-modified-label", default_value = "")]
     /// Text to display in front of a modified file path.
     pub file_modified_label: String,
diff --git a/src/config.rs b/src/config.rs
index 12b82945..1c28d060 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -113,7 +113,7 @@ pub struct Config {
     pub minus_file: Option<PathBuf>,
     pub minus_non_emph_style: Style,
     pub minus_style: Style,
-    pub navigate_regexp: Option<String>,
+    pub navigate_regex: Option<String>,
     pub navigate: bool,
     pub null_style: Style,
     pub null_syntect_style: SyntectStyle,
@@ -208,8 +208,10 @@ impl From<cli::Opt> for Config {
             side_by_side_data,
         );
 
-        let navigate_regexp = if opt.navigate || opt.show_themes {
-            Some(navigate::make_navigate_regexp(
+        let navigate_regex = if (opt.navigate || opt.show_themes)
+            && (opt.navigate_regex.is_none() || opt.navigate_regex == Some("".to_string()))
+        {
+            Some(navigate::make_navigate_regex(
                 opt.show_themes,
                 &file_modified_label,
                 &file_added_label,
@@ -218,7 +220,7 @@ impl From<cli::Opt> for Config {
                 &hunk_label,
             ))
         } else {
-            None
+            opt.navigate_regex
         };
 
         let wrap_max_lines_plus1 = adapt_wrap_max_lines_argument(opt.wrap_max_lines);
@@ -320,7 +322,7 @@ impl From<cli::Opt> for Config {
             minus_non_emph_style: styles["minus-non-emph-style"],
             minus_style: styles["minus-style"],
             navigate: opt.navigate,
-            navigate_regexp,
+            navigate_regex,
             null_style: Style::new(),
             null_syntect_style: SyntectStyle::default(),
             pager: opt.pager,
diff --git a/src/features/navigate.rs b/src/features/navigate.rs
index cb5fb144..60182907 100644
--- a/src/features/navigate.rs
+++ b/src/features/navigate.rs
@@ -30,7 +30,7 @@ pub fn make_feature() -> Vec<(String, OptionValueFunction)> {
 }
 
 // Construct the regexp used by less for paging, if --show-themes or --navigate is enabled.
-pub fn make_navigate_regexp(
+pub fn make_navigate_regex(
     show_themes: bool,
     file_modified_label: &str,
     file_added_label: &str,
@@ -41,27 +41,34 @@ pub fn make_navigate_regexp(
     if show_themes {
         "^Theme:".to_string()
     } else {
+        let optional_regexp = |find: &str| {
+            if !find.is_empty() {
+                format!("|{}", regex::escape(find))
+            } else {
+                "".to_string()
+            }
+        };
         format!(
-            "^(commit|{}|{}|{}|{}|{})",
-            regex::escape(file_added_label),
-            regex::escape(file_removed_label),
-            regex::escape(file_renamed_label),
-            regex::escape(file_modified_label),
-            regex::escape(hunk_label),
+            "^(commit{}{}{}{}{})",
+            optional_regexp(file_added_label),
+            optional_regexp(file_removed_label),
+            optional_regexp(file_renamed_label),
+            optional_regexp(file_modified_label),
+            optional_regexp(hunk_label),
         )
     }
 }
 
 // Create a less history file to be used by delta's child less process. This file is initialized
-// with the contents of user's real less hist file, to which the navigate regexp is appended. This
-// has the effect that 'n' or 'N' in delta's less process will search for the navigate regexp,
+// with the contents of user's real less hist file, to which the navigate regex is appended. This
+// has the effect that 'n' or 'N' in delta's less process will search for the navigate regex,
 // without the undesirable aspects of using --pattern, yet without polluting the user's less search
-// history with delta's navigate regexp. See
+// history with delta's navigate regex. See
 // https://github.com/dandavison/delta/issues/237#issuecomment-780654036. Note that with the
 // current implementation, no writes to the delta less history file are propagated back to the real
 // history file so, for example, a (non-navigate) search performed in the delta less process will
 // not be stored in history.
-pub fn copy_less_hist_file_and_append_navigate_regexp(config: &Config) -> std::io::Result<PathBuf> {
+pub fn copy_less_hist_file_and_append_navigate_regex(config: &Config) -> std::io::Result<PathBuf> {
     let delta_less_hist_file = get_delta_less_hist_file()?;
     let initial_contents = ".less-history-file:\n".to_string();
     let mut contents = if let Some(hist_file) = get_less_hist_file() {
@@ -76,7 +83,7 @@ pub fn copy_less_hist_file_and_append_navigate_regexp(config: &Config) -> std::i
         std::fs::File::create(&delta_less_hist_file)?,
         "{}\"{}",
         contents,
-        config.navigate_regexp.as_ref().unwrap(),
+        config.navigate_regex.as_ref().unwrap(),
     )?;
     Ok(delta_less_hist_file)
 }
diff --git a/src/handlers/hunk_header.rs b/src/handlers/hunk_header.rs
index 1a336992..dd851509 100644
--- a/src/handlers/hunk_header.rs
+++ b/src/handlers/hunk_header.rs
@@ -230,7 +230,7 @@ fn write_to_output_buffer(
     painter: &mut Painter,
     config: &Config,
 ) {
-    if config.navigate {
+    if !config.hunk_label.is_empty() {
         let _ = write!(
             &mut painter.output_buffer,
             "{} ",
diff --git a/src/options/set.rs b/src/options/set.rs
index faa2398b..b1dd49d0 100644
--- a/src/options/set.rs
+++ b/src/options/set.rs
@@ -167,6 +167,7 @@ pub fn set_options(
             minus_non_emph_style,
             minus_non_emph_style,
             navigate,
+            navigate_regex,
             line_fill_method,
             line_numbers,
             line_numbers_left_format,
@@ -696,6 +697,7 @@ pub mod tests {
     minus-non-emph-style = black black
     minus-style = black black
     navigate = true
+    navigate-regex = xxxyyyzzz
     paging = never
     plus-emph-style = black black
     plus-empty-line-marker-style = black black
@@ -756,6 +758,7 @@ pub mod tests {
         assert_eq!(opt.minus_non_emph_style, "black black");
         assert_eq!(opt.minus_style, "black black");
         assert_eq!(opt.navigate, true);
+        assert_eq!(opt.navigate_regex, Some("xxxyyyzzz".to_string()));
         assert_eq!(opt.paging_mode, "never");
         assert_eq!(opt.plus_emph_style, "black black");
         assert_eq!(opt.plus_empty_line_marker_style, "black black");
diff --git a/src/subcommands/show_config.rs b/src/subcommands/show_config.rs
index 594dca68..cf86d09d 100644
--- a/src/subcommands/show_config.rs
+++ b/src/subcommands/show_config.rs
@@ -117,7 +117,7 @@ pub fn show_config(config: &config::Config, writer: &mut dyn Write) -> std::io::
     max-line-length               = {max_line_length}
     line-fill-method              = {line_fill_method}
     navigate                      = {navigate}
-    navigate-regexp               = {navigate_regexp}
+    navigate-regex                = {navigate_regex}
     pager                         = {pager}
     paging                        = {paging_mode}
     side-by-side                  = {side_by_side}
@@ -132,9 +132,9 @@ pub fn show_config(config: &config::Config, writer: &mut dyn Write) -> std::io::
             BgFillMethod::Spaces => "spaces",
         },
         navigate = config.navigate,
-        navigate_regexp = match &config.navigate_regexp {
+        navigate_regex = match &config.navigate_regex {
             None => "".to_string(),
-            Some(s) => s.to_string(),
+            Some(s) => format_option_value(s.to_string()),
         },
         pager = config.pager.clone().unwrap_or_else(|| "none".to_string()),
         paging_mode = match config.paging_mode {
diff --git a/src/utils/bat/output.rs b/src/utils/bat/output.rs
index a231168b..62761c25 100644
--- a/src/utils/bat/output.rs
+++ b/src/utils/bat/output.rs
@@ -162,8 +162,7 @@ fn _make_process_from_less_path(
         p.env("LESSCHARSET", "UTF-8");
         p.env("LESSANSIENDCHARS", "mK");
         if config.navigate {
-            if let Ok(hist_file) = navigate::copy_less_hist_file_and_append_navigate_regexp(config)
-            {
+            if let Ok(hist_file) = navigate::copy_less_hist_file_and_append_navigate_regex(config) {
                 p.env("LESSHISTFILE", hist_file);
                 if config.show_themes {
                     p.arg("+n");