Handle grep output769-git-grep-rebase

- Handle standard filepath:code and filepath:line_number:code output
  as produced by `git grep`, `rg -H`, `grep -H`, etc (with -n for line
  numbers).

- Retain the match highlighting as produced by the grep tool, and
  expose it in delta's color output styled with grep-match-style.
  (Note that --color=always is needed to retain the color if piping
  into delta, but not for `git grep` when delta is configured as git's
  pager)

- Special handling of -p, and -W options of `git grep`: these display
  the function context in which the matches occur.

- `navigate` keybindings jump between match function contexts under
  `git grep -p` and between matching lines under `git grep -W`.

Thanks @zachriggle for the proposal.
Fixes #769

1 files changed, 34 insertions, 0 deletions

diff --git a/src/cli.rs b/src/cli.rs
index aa40ce1e..1d0c7640 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -441,6 +441,40 @@ pub struct Opt {
     )]
     pub blame_timestamp_format: String,
 
+    #[structopt(long = "grep-match-line-style")]
+    /// Style (foreground, background, attributes) for matching lines of code in
+    /// grep output. See STYLES section. Defaults to plus-style.
+    pub grep_match_line_style: Option<String>,
+
+    #[structopt(long = "grep-match-word-style")]
+    /// Style (foreground, background, attributes) for the specific matching
+    /// substrings within a matching line of code in grep output. See STYLES
+    /// section. Defaults to plus-style.
+    pub grep_match_word_style: Option<String>,
+
+    #[structopt(long = "grep-context-line-style")]
+    /// Style (foreground, background, attributes) for non-matching lines of
+    /// code in grep output. See STYLES section. Defaults to zero-style.
+    pub grep_context_line_style: Option<String>,
+
+    #[structopt(long = "grep-file-style")]
+    /// Style (foreground, background, attributes) for file paths in grep
+    /// output. See STYLES section. Defaults to hunk-header-file-path-style.
+    pub grep_file_style: Option<String>,
+
+    #[structopt(long = "grep-line-number-style")]
+    /// Style (foreground, background, attributes) for line numbers in grep
+    /// output. See STYLES section. Defaults to hunk-header-line-number-style.
+    pub grep_line_number_style: Option<String>,
+
+    #[structopt(long = "grep-separator-symbol", default_value = ":")]
+    /// Symbol used in grep output to separate file path (and line number) from
+    /// the line of file contents. Defaults to ":" for both match and context
+    /// lines, since many terminal emulators recognize constructs like
+    /// "/path/to/file:7:". However, standard grep output uses "-" for context
+    /// lines: set this option to "keep" to keep the original separator symbols.
+    pub grep_separator_symbol: String,
+
     /// Default language used for syntax highlighting when this cannot be
     /// inferred from a filename. It will typically make sense to set this in
     /// per-repository git config (.git/config)