Add a flag to anchor patterns in the input

Closes sharkdp#1476.

src/cli.rs

@@ -168,8 +168,8 @@ pub struct Opts {
  pub regex: bool,
 
  /// Treat the pattern as a literal string instead of a regular expression. Note
- /// that this also performs substring comparison. If you want to match on an
- /// exact filename, consider using '--glob'.
+ /// that the pattern would still match on a substring of the input. If you want
+ /// to match on an exact filename, consider adding '--anchor=input' as well.
  #[arg(
  long,
  short = 'F',
@@ -246,6 +246,20 @@ pub struct Opts {
  )]
  pub full_path: bool,
 
+ /// By default, the search pattern for --regex and --fixed-strings can match any part of the input.
+ /// (See the --full-path option for what constitutes input)
+ ///
+ /// This flag allows other ways to anchor the pattern.
+ ///
+ /// Conflicts with the --glob flag: globs always match the entire input
+ #[arg(
+ long,
+ help = "Where to anchor the pattern",
+ conflicts_with("glob"),
+ long_help
+ )]
+ pub anchor: Option<Anchor>,
+
  /// Separate search results by the null character (instead of newlines).
  /// Useful for piping results to 'xargs'.
  #[arg(
@@ -680,6 +694,17 @@ impl Opts {
  self.rg_alias_hidden_ignore > 0
  }
 
+ pub fn anchor(&self) -> Option<Anchor> {
+ if self.glob {
+ // globset has no way to use an anchor.
+ // Otherwise we'd guard like this:
+ // && !self.no_anchor && self.anchor.is_none()
+ Some(Anchor::Input)
+ } else {
+ self.anchor
+ }
+ }
+
  pub fn max_depth(&self) -> Option<usize> {
  self.max_depth.or(self.exact_depth)
  }
@@ -725,6 +750,14 @@ fn default_num_threads() -> NonZeroUsize {
  .min(limit)
 }
 
+#[derive(Copy, Clone, PartialEq, Eq, ValueEnum)]
+pub enum Anchor {
+ InputStart,
+ InputEnd,
+ Input,
+ Word,
+}
+
 #[derive(Copy, Clone, PartialEq, Eq, ValueEnum)]
 pub enum FileType {
  #[value(alias = "f")]

src/main.rs

@@ -162,15 +162,36 @@ fn ensure_search_pattern_is_not_a_path(opts: &Opts) -> Result<()> {
  }
 }
 
+fn apply_anchors(re: String, anchors: Option<cli::Anchor>) -> String {
+ use cli::Anchor;
+ match anchors {
+ None => re,
+ Some(Anchor::InputStart) => "^".to_owned() + &re,
+ Some(Anchor::InputEnd) => re + "$",
+ Some(Anchor::Input) => "^".to_owned() + &re + "$",
+ // https://docs.rs/regex/latest/regex/#empty-matches
+ Some(Anchor::Word) => r"\<".to_owned() + &re + r"\>",
+ }
+}
+
 fn build_pattern_regex(pattern: &str, opts: &Opts) -> Result<String> {
- Ok(if opts.glob && !pattern.is_empty() {
- let glob = GlobBuilder::new(pattern).literal_separator(true).build()?;
- glob.regex().to_owned()
- } else if opts.fixed_strings {
- // Treat pattern as literal string if '--fixed-strings' is used
- regex::escape(pattern)
+ Ok(if opts.glob {
+ if !pattern.is_empty() {
+ let glob = GlobBuilder::new(pattern).literal_separator(true).build()?;
+ glob.regex().to_owned()
+ } else {
+ "".to_owned()
+ }
  } else {
- String::from(pattern)
+ apply_anchors(
+ if opts.fixed_strings {
+ // Treat pattern as literal string if '--fixed-strings' is used
+ regex::escape(pattern)
+ } else {
+ String::from(pattern)
+ },
+ opts.anchor(),
+ )
  })
 }