diff -r 5d4ec64a6fcb -r e8f3740cc067 rust/hg-core/src/lib.rs
--- a/rust/hg-core/src/lib.rs	Wed May 15 22:11:41 2019 -0700
+++ b/rust/hg-core/src/lib.rs	Wed Apr 24 11:34:09 2019 +0200
@@ -4,6 +4,9 @@
 // GNU General Public License version 2 or any later version.
 extern crate byteorder;
 extern crate memchr;
+#[macro_use]
+extern crate lazy_static;
+extern crate regex;
 
 mod ancestors;
 pub mod dagops;
@@ -15,6 +18,11 @@
     pack_dirstate, parse_dirstate, CopyVec, CopyVecEntry, DirstateEntry,
     DirstateParents, DirstateVec,
 };
+mod filepatterns;
+
+pub use filepatterns::{
+    build_single_regex, read_pattern_file, PatternSyntax, PatternTuple,
+};
 
 /// Mercurial revision numbers
 ///
@@ -42,6 +50,8 @@
     fn parents(&self, Revision) -> Result<[Revision; 2], GraphError>;
 }
 
+pub type LineNumber = usize;
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum GraphError {
     ParentOutOfRange(Revision),
@@ -73,3 +83,20 @@
         DirstateParseError::CorruptedEntry(e.to_string())
     }
 }
+
+#[derive(Debug)]
+pub enum PatternError {
+    UnsupportedSyntax(String),
+}
+
+#[derive(Debug)]
+pub enum PatternFileError {
+    IO(std::io::Error),
+    Pattern(PatternError, LineNumber),
+}
+
+impl From<std::io::Error> for PatternFileError {
+    fn from(e: std::io::Error) -> Self {
+        PatternFileError::IO(e)
+    }
+}