Add context-around-highlight option

src/bin/bat/app.rs

@@ -7,6 +7,7 @@ use crate::{
  clap_app,
  config::{get_args_from_config_file, get_args_from_env_opts_var, get_args_from_env_vars},
 };
+use bat::line_range;
 use clap::ArgMatches;
 
 use console::Term;
@@ -255,14 +256,42 @@ impl App {
  .unwrap_or(2),
  ),
 
- _ => VisibleLines::Ranges(
- self.matches
+ _ => VisibleLines::Ranges({
+ let line_range = self
+ .matches
  .get_many::<String>("line-range")
  .map(|vs| vs.map(|s| LineRange::from(s.as_str())).collect())
  .transpose()?
- .map(LineRanges::from)
- .unwrap_or_default(),
- ),
+ .map(LineRanges::from);
+
+ let context = self
+ .matches
+ .get_one::<String>("context-around-highlight")
+ .and_then(|s| usize::from_str_radix(s, 10).ok())
+ .unwrap_or_else(|| 0);
+ let range_due_to_highlighted_lines = self
+ .matches
+ .get_many::<String>("highlight-line")
+ .map(|ws| {
+ ws.map(|s| {
+ let lr = LineRange::from(s.as_str());
+ lr.map(|line_range| {
+ LineRange::new(
+ line_range.get_lower().saturating_sub(context),
+ line_range.get_upper().saturating_add(context),
+ )
+ })
+ })
+ .collect()
+ })
+ .transpose()?
+ .map(LineRanges::from);
+ match ( line_range, range_due_to_highlighted_lines ) {
+ ( Some(range), None ) | ( None, Some(range) ) => range,
+ ( None, None ) => LineRanges::default(),
+ _ => unreachable!("line-range and context-around-highlight are conflicting, so this is impossible")
+ }
+ }),
  },
  style_components,
  syntax_mapping,

src/bin/bat/clap_app.rs

@@ -120,6 +120,16 @@ pub fn build_app(interactive_output: bool) -> Command {
  '--highlight-line 30:+10' highlights lines 30 to 40",
  ),
  )
+ .arg(
+ Arg::new("context-around-highlight")
+ .long("context-around-highlight")
+ .action(ArgAction::Set)
+ .requires("highlight-line")
+ .conflicts_with("line-range")
+ .conflicts_with("diff")
+ .value_name("N")
+ .help("Show lines from highlighted line - N through highlighted line + N"),
+ )
  .arg(
  Arg::new("file-name")
  .long("file-name")

src/line_range.rs

@@ -77,6 +77,12 @@ impl LineRange {
  ),
  }
  }
+ pub fn get_lower(&self) -> usize {
+ self.lower
+ }
+ pub fn get_upper(&self) -> usize {
+ self.upper
+ }
 
  pub(crate) fn is_inside(&self, line: usize) -> bool {
  line >= self.lower && line <= self.upper