Upgrade rust/crates/unicode-segmentation to 1.8.0 am: cdef32ccc4 am: 6cb7f46ab3 am: ab4c798bfc

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/unicode-segmentation/+/1791075

Change-Id: Id7b1e6bf54f3b65b6638402d5cc0dd10bfb4673c

17 files changed, 321 insertions, 85 deletions

diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
index 22f2cec..e74a153 100644
--- a/.cargo_vcs_info.json
+++ b/.cargo_vcs_info.json
@@ -1,5 +1,5 @@
 {
   "git": {
-    "sha1": "3b75ee19b3c0ddacaeec03be688a7b8766833728"
+    "sha1": "907d4d0b7e5c6f5e0f815c90a51d28b793d0c7a4"
   }
 }
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
new file mode 100644
index 0000000..3c13d1b
--- /dev/null
+++ b/.github/workflows/rust.yml
@@ -0,0 +1,22 @@
+name: Rust
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Build
+      run: cargo build --verbose
+    - name: Run tests
+      run: cargo test --verbose
diff --git a/Android.bp b/Android.bp
index da0cf0d..aaf1015 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,4 +1,5 @@
 // This file is generated by cargo2android.py --run --device --dependencies.
+// Do not modify this file as changes will be overridden on upgrade.
 
 package {
     default_applicable_licenses: [
@@ -41,9 +42,8 @@ license {
 
 rust_library {
     name: "libunicode_segmentation",
-    // has rustc warnings
     host_supported: true,
     crate_name: "unicode_segmentation",
     srcs: ["src/lib.rs"],
-    edition: "2015",
+    edition: "2018",
 }
diff --git a/Cargo.toml b/Cargo.toml
index 0f21309..583df10 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,8 +11,9 @@
 # will likely look very different (and much more reasonable)
 
 [package]
+edition = "2018"
 name = "unicode-segmentation"
-version = "1.7.1"
+version = "1.8.0"
 authors = ["kwantam <kwantam@gmail.com>", "Manish Goregaokar <manishsmail@gmail.com>"]
 exclude = ["target/*", "Cargo.lock", "scripts/tmp", "benches/texts/*", "*.txt"]
 description = "This crate provides Grapheme Cluster, Word and Sentence boundaries\naccording to Unicode Standard Annex #29 rules.\n"
@@ -26,8 +27,16 @@ repository = "https://github.com/unicode-rs/unicode-segmentation"
 [[bench]]
 name = "graphemes"
 harness = false
-[dev-dependencies.bencher]
-version = "0.1"
+
+[[bench]]
+name = "unicode_words"
+harness = false
+
+[[bench]]
+name = "word_bounds"
+harness = false
+[dev-dependencies.criterion]
+version = "0.3"
 
 [dev-dependencies.quickcheck]
 version = "0.7"
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
index 3f55167..c1c16e6 100644
--- a/Cargo.toml.orig
+++ b/Cargo.toml.orig
@@ -1,9 +1,10 @@
 [package]
 
 name = "unicode-segmentation"
-version = "1.7.1"
+version = "1.8.0"
 authors = ["kwantam <kwantam@gmail.com>", "Manish Goregaokar <manishsmail@gmail.com>"]
 
+edition = "2018"
 homepage = "https://github.com/unicode-rs/unicode-segmentation"
 repository = "https://github.com/unicode-rs/unicode-segmentation"
 documentation = "https://unicode-rs.github.io/unicode-segmentation"
@@ -23,8 +24,16 @@ no_std = [] # This is a no-op, preserved for backward compatibility only.
 
 [dev-dependencies]
 quickcheck = "0.7"
-bencher = "0.1"
+criterion = "0.3"
 
 [[bench]]
 name = "graphemes"
+harness = false
+
+[[bench]]
+name = "unicode_words"
+harness = false
+
+[[bench]]
+name = "word_bounds"
 harness = false
\ No newline at end of file
diff --git a/METADATA b/METADATA
index bf983b5..00df7c3 100644
--- a/METADATA
+++ b/METADATA
@@ -7,13 +7,13 @@ third_party {
   }
   url {
     type: ARCHIVE
-    value: "https://static.crates.io/crates/unicode-segmentation/unicode-segmentation-1.7.1.crate"
+    value: "https://static.crates.io/crates/unicode-segmentation/unicode-segmentation-1.8.0.crate"
   }
-  version: "1.7.1"
+  version: "1.8.0"
   license_type: NOTICE
   last_upgrade_date {
     year: 2021
-    month: 1
-    day: 12
+    month: 8
+    day: 9
   }
 }
diff --git a/README.md b/README.md
index 2f3bdca..a65c0e2 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,7 @@ to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-unicode-segmentation = "1.7.1"
+unicode-segmentation = "1.8.0"
 ```
 
 # Change Log
diff --git a/benches/graphemes.rs b/benches/graphemes.rs
index 5f14352..8a7a379 100644
--- a/benches/graphemes.rs
+++ b/benches/graphemes.rs
@@ -1,55 +1,54 @@
-#[macro_use]
-extern crate bencher;
-extern crate unicode_segmentation;
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use unicode_segmentation;
 
-use bencher::Bencher;
-use unicode_segmentation::UnicodeSegmentation;
 use std::fs;
+use unicode_segmentation::UnicodeSegmentation;
 
-fn graphemes(bench: &mut Bencher, path: &str) {
+fn graphemes(c: &mut Criterion, lang: &str, path: &str) {
     let text = fs::read_to_string(path).unwrap();
-    bench.iter(|| {
-        for g in UnicodeSegmentation::graphemes(&*text, true) {
-            bencher::black_box(g);
-        }
-    });
 
-    bench.bytes = text.len() as u64;
+    c.bench_function(&format!("graphemes_{}",lang), |bench| {
+        bench.iter(|| {
+            for g in UnicodeSegmentation::graphemes(black_box(&*text), true) {
+                black_box(g);
+            }
+        })
+    });
 }
 
-fn graphemes_arabic(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/arabic.txt");
+fn graphemes_arabic(c: &mut Criterion) {
+    graphemes(c, "arabic" ,"benches/texts/arabic.txt");
 }
 
-fn graphemes_english(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/english.txt");
+fn graphemes_english(c: &mut Criterion) {
+    graphemes(c, "english" ,"benches/texts/english.txt");
 }
 
-fn graphemes_hindi(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/hindi.txt");
+fn graphemes_hindi(c: &mut Criterion) {
+    graphemes(c, "hindi" ,"benches/texts/hindi.txt");
 }
 
-fn graphemes_japanese(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/japanese.txt");
+fn graphemes_japanese(c: &mut Criterion) {
+    graphemes(c, "japanese" ,"benches/texts/japanese.txt");
 }
 
-fn graphemes_korean(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/korean.txt");
+fn graphemes_korean(c: &mut Criterion) {
+    graphemes(c, "korean" ,"benches/texts/korean.txt");
 }
 
-fn graphemes_mandarin(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/mandarin.txt");
+fn graphemes_mandarin(c: &mut Criterion) {
+    graphemes(c, "mandarin" ,"benches/texts/mandarin.txt");
 }
 
-fn graphemes_russian(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/russian.txt");
+fn graphemes_russian(c: &mut Criterion) {
+    graphemes(c, "russian" ,"benches/texts/russian.txt");
 }
 
-fn graphemes_source_code(bench: &mut Bencher) {
-    graphemes(bench, "benches/texts/source_code.txt");
+fn graphemes_source_code(c: &mut Criterion) {
+    graphemes(c, "source_code","benches/texts/source_code.txt");
 }
 
-benchmark_group!(
+criterion_group!(
     benches,
     graphemes_arabic,
     graphemes_english,
@@ -61,4 +60,4 @@ benchmark_group!(
     graphemes_source_code,
 );
 
-benchmark_main!(benches);
+criterion_main!(benches);
diff --git a/benches/unicode_words.rs b/benches/unicode_words.rs
new file mode 100644
index 0000000..731e325
--- /dev/null
+++ b/benches/unicode_words.rs
@@ -0,0 +1,64 @@
+#[macro_use]
+extern crate bencher;
+extern crate unicode_segmentation;
+
+use bencher::Bencher;
+use unicode_segmentation::UnicodeSegmentation;
+use std::fs;
+
+fn unicode_words(bench: &mut Bencher, path: &str) {
+    let text = fs::read_to_string(path).unwrap();
+    bench.iter(|| {
+        for w in text.unicode_words() {
+            bencher::black_box(w);
+        }
+    });
+
+    bench.bytes = text.len() as u64;
+}
+
+fn unicode_words_arabic(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/arabic.txt");
+}
+
+fn unicode_words_english(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/english.txt");
+}
+
+fn unicode_words_hindi(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/hindi.txt");
+}
+
+fn unicode_words_japanese(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/japanese.txt");
+}
+
+fn unicode_words_korean(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/korean.txt");
+}
+
+fn unicode_words_mandarin(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/mandarin.txt");
+}
+
+fn unicode_words_russian(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/russian.txt");
+}
+
+fn unicode_words_source_code(bench: &mut Bencher) {
+    unicode_words(bench, "benches/texts/source_code.txt");
+}
+
+benchmark_group!(
+    benches,
+    unicode_words_arabic,
+    unicode_words_english,
+    unicode_words_hindi,
+    unicode_words_japanese,
+    unicode_words_korean,
+    unicode_words_mandarin,
+    unicode_words_russian,
+    unicode_words_source_code,
+);
+
+benchmark_main!(benches);
diff --git a/benches/word_bounds.rs b/benches/word_bounds.rs
new file mode 100644
index 0000000..035f57e
--- /dev/null
+++ b/benches/word_bounds.rs
@@ -0,0 +1,64 @@
+#[macro_use]
+extern crate bencher;
+extern crate unicode_segmentation;
+
+use bencher::Bencher;
+use unicode_segmentation::UnicodeSegmentation;
+use std::fs;
+
+fn word_bounds(bench: &mut Bencher, path: &str) {
+    let text = fs::read_to_string(path).unwrap();
+    bench.iter(|| {
+        for w in text.split_word_bounds() {
+            bencher::black_box(w);
+        }
+    });
+
+    bench.bytes = text.len() as u64;
+}
+
+fn word_bounds_arabic(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/arabic.txt");
+}
+
+fn word_bounds_english(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/english.txt");
+}
+
+fn word_bounds_hindi(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/hindi.txt");
+}
+
+fn word_bounds_japanese(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/japanese.txt");
+}
+
+fn word_bounds_korean(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/korean.txt");
+}
+
+fn word_bounds_mandarin(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/mandarin.txt");
+}
+
+fn word_bounds_russian(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/russian.txt");
+}
+
+fn word_bounds_source_code(bench: &mut Bencher) {
+    word_bounds(bench, "benches/texts/source_code.txt");
+}
+
+benchmark_group!(
+    benches,
+    word_bounds_arabic,
+    word_bounds_english,
+    word_bounds_hindi,
+    word_bounds_japanese,
+    word_bounds_korean,
+    word_bounds_mandarin,
+    word_bounds_russian,
+    word_bounds_source_code,
+);
+
+benchmark_main!(benches);
diff --git a/scripts/unicode.py b/scripts/unicode.py
index 1841e35..16e321d 100644
--- a/scripts/unicode.py
+++ b/scripts/unicode.py
@@ -229,7 +229,7 @@ pub mod util {
     #[inline]
     fn is_alphabetic(c: char) -> bool {
         match c {
-            'a' ... 'z' | 'A' ... 'Z' => true,
+            'a' ..= 'z' | 'A' ..= 'Z' => true,
             c if c > '\x7f' => super::derived_property::Alphabetic(c),
             _ => false,
         }
@@ -238,7 +238,7 @@ pub mod util {
     #[inline]
     fn is_numeric(c: char) -> bool {
         match c {
-            '0' ... '9' => true,
+            '0' ..= '9' => true,
             c if c > '\x7f' => super::general_category::N(c),
             _ => false,
         }
@@ -281,7 +281,6 @@ def emit_break_module(f, break_table, break_cats, name):
     f.write("""    }
 
     fn bsearch_range_value_table(c: char, r: &'static [(char, char, %sCat)]) -> (u32, u32, %sCat) {
-        use core;
         use core::cmp::Ordering::{Equal, Less, Greater};
         match r.binary_search_by(|&(lo, hi, _)| {
             if lo <= c && c <= hi { Equal }
diff --git a/src/grapheme.rs b/src/grapheme.rs
index e95d478..190b86e 100644
--- a/src/grapheme.rs
+++ b/src/grapheme.rs
@@ -10,7 +10,7 @@
 
 use core::cmp;
 
-use tables::grapheme::GraphemeCat;
+use crate::tables::grapheme::GraphemeCat;
 
 /// External iterator for grapheme clusters and byte offsets.
 ///
@@ -73,7 +73,7 @@ impl<'a> DoubleEndedIterator for GraphemeIndices<'a> {
 ///
 /// [`graphemes`]: trait.UnicodeSegmentation.html#tymethod.graphemes
 /// [`UnicodeSegmentation`]: trait.UnicodeSegmentation.html
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Graphemes<'a> {
     string: &'a str,
     cursor: GraphemeCursor,
@@ -148,7 +148,7 @@ pub fn new_grapheme_indices<'b>(s: &'b str, is_extended: bool) -> GraphemeIndice
 
 // maybe unify with PairResult?
 // An enum describing information about a potential boundary.
-#[derive(PartialEq, Eq, Clone)]
+#[derive(PartialEq, Eq, Clone, Debug)]
 enum GraphemeState {
     // No information is known.
     Unknown,
@@ -165,7 +165,7 @@ enum GraphemeState {
 }
 
 /// Cursor-based segmenter for grapheme clusters.
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct GraphemeCursor {
     // Current cursor position.
     offset: usize,
@@ -228,8 +228,9 @@ enum PairResult {
     Emoji,  // a break if preceded by emoji base and (Extend)*
 }
 
+#[inline]
 fn check_pair(before: GraphemeCat, after: GraphemeCat) -> PairResult {
-    use tables::grapheme::GraphemeCat::*;
+    use crate::tables::grapheme::GraphemeCat::*;
     use self::PairResult::*;
     match (before, after) {
         (GC_CR, GC_LF) => NotBreak,  // GB3
@@ -295,8 +296,8 @@ impl GraphemeCursor {
     }
 
     fn grapheme_category(&mut self, ch: char) -> GraphemeCat {
-        use tables::grapheme as gr;
-        use tables::grapheme::GraphemeCat::*;
+        use crate::tables::grapheme as gr;
+        use crate::tables::grapheme::GraphemeCat::*;
 
         if ch <= '\u{7e}' {
             // Special-case optimization for ascii, except U+007F.  This
@@ -387,7 +388,7 @@ impl GraphemeCursor {
     /// assert_eq!(cursor.is_boundary(&flags[8..], 8), Ok(true));
     /// ```
     pub fn provide_context(&mut self, chunk: &str, chunk_start: usize) {
-        use tables::grapheme as gr;
+        use crate::tables::grapheme as gr;
         assert!(chunk_start + chunk.len() == self.pre_context_offset.unwrap());
         self.pre_context_offset = None;
         if self.is_extended && chunk_start + chunk.len() == self.offset {
@@ -407,6 +408,7 @@ impl GraphemeCursor {
         }
     }
 
+    #[inline]
     fn decide(&mut self, is_break: bool) {
         self.state = if is_break {
             GraphemeState::Break
@@ -415,11 +417,13 @@ impl GraphemeCursor {
         };
     }
 
+    #[inline]
     fn decision(&mut self, is_break: bool) -> Result<bool, GraphemeIncomplete> {
         self.decide(is_break);
         Ok(is_break)
     }
 
+    #[inline]
     fn is_boundary_result(&self) -> Result<bool, GraphemeIncomplete> {
         if self.state == GraphemeState::Break {
             Ok(true)
@@ -432,8 +436,9 @@ impl GraphemeCursor {
         }
     }
 
+    #[inline]
     fn handle_regional(&mut self, chunk: &str, chunk_start: usize) {
-        use tables::grapheme as gr;
+        use crate::tables::grapheme as gr;
         let mut ris_count = self.ris_count.unwrap_or(0);
         for ch in chunk.chars().rev() {
             if self.grapheme_category(ch) != gr::GC_Regional_Indicator {
@@ -452,8 +457,9 @@ impl GraphemeCursor {
         self.state = GraphemeState::Regional;
     }
 
+    #[inline]
     fn handle_emoji(&mut self, chunk: &str, chunk_start: usize) {
-        use tables::grapheme as gr;
+        use crate::tables::grapheme as gr;
         let mut iter = chunk.chars().rev();
         if let Some(ch) = iter.next() {
             if self.grapheme_category(ch) != gr::GC_ZWJ {
@@ -482,6 +488,7 @@ impl GraphemeCursor {
         self.state = GraphemeState::Emoji;
     }
 
+    #[inline]
     /// Determine whether the current cursor location is a grapheme cluster boundary.
     /// Only a part of the string need be supplied. If `chunk_start` is nonzero or
     /// the length of `chunk` is not equal to `len` on creation, then this method
@@ -506,7 +513,7 @@ impl GraphemeCursor {
     /// assert_eq!(cursor.is_boundary(flags, 0), Ok(false));
     /// ```
     pub fn is_boundary(&mut self, chunk: &str, chunk_start: usize) -> Result<bool, GraphemeIncomplete> {
-        use tables::grapheme as gr;
+        use crate::tables::grapheme as gr;
         if self.state == GraphemeState::Break {
             return Ok(true)
         }
@@ -563,6 +570,7 @@ impl GraphemeCursor {
         }
     }
 
+    #[inline]
     /// Find the next boundary after the current cursor position. Only a part of
     /// the string need be supplied. If the chunk is incomplete, then this
     /// method might return `GraphemeIncomplete::PreContext` or
diff --git a/src/lib.rs b/src/lib.rs
index 571e33a..6077bbd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -66,7 +66,7 @@ extern crate quickcheck;
 pub use grapheme::{Graphemes, GraphemeIndices};
 pub use grapheme::{GraphemeCursor, GraphemeIncomplete};
 pub use tables::UNICODE_VERSION;
-pub use word::{UWordBounds, UWordBoundIndices, UnicodeWords};
+pub use word::{UWordBounds, UWordBoundIndices, UnicodeWords, UnicodeWordIndices};
 pub use sentence::{USentenceBounds, USentenceBoundIndices, UnicodeSentences};
 
 mod grapheme;
@@ -146,6 +146,30 @@ pub trait UnicodeSegmentation {
     /// ```
     fn unicode_words<'a>(&'a self) -> UnicodeWords<'a>;
 
+    /// Returns an iterator over the words of `self`, separated on
+    /// [UAX#29 word boundaries](http://www.unicode.org/reports/tr29/#Word_Boundaries), and their
+    /// offsets.
+    ///
+    /// Here, "words" are just those substrings which, after splitting on
+    /// UAX#29 word boundaries, contain any alphanumeric characters. That is, the
+    /// substring must contain at least one character with the
+    /// [Alphabetic](http://unicode.org/reports/tr44/#Alphabetic)
+    /// property, or with
+    /// [General_Category=Number](http://unicode.org/reports/tr44/#General_Category_Values).
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use self::unicode_segmentation::UnicodeSegmentation;
+    /// let uwis = "The quick (\"brown\") fox can't jump 32.3 feet, right?";
+    /// let uwi1 = uwis.unicode_word_indices().collect::<Vec<(usize, &str)>>();
+    /// let b: &[_] = &[(0, "The"), (4, "quick"), (12, "brown"), (20, "fox"), (24, "can't"),
+    ///                 (30, "jump"), (35, "32.3"), (40, "feet"), (46, "right")];
+    ///
+    /// assert_eq!(&uwi1[..], b);
+    /// ```
+    fn unicode_word_indices<'a>(&'a self) -> UnicodeWordIndices<'a>;
+
     /// Returns an iterator over substrings of `self` separated on
     /// [UAX#29 word boundaries](http://www.unicode.org/reports/tr29/#Word_Boundaries).
     ///
@@ -250,6 +274,11 @@ impl UnicodeSegmentation for str {
     }
 
     #[inline]
+    fn unicode_word_indices(&self) -> UnicodeWordIndices {
+        word::new_unicode_word_indices(self)
+    }
+
+    #[inline]
     fn split_word_bounds(&self) -> UWordBounds {
         word::new_word_bounds(self)
     }
diff --git a/src/sentence.rs b/src/sentence.rs
index 275da52..0a23abd 100644
--- a/src/sentence.rs
+++ b/src/sentence.rs
@@ -13,7 +13,7 @@ use core::iter::Filter;
 
 // All of the logic for forward iteration over sentences
 mod fwd {
-    use tables::sentence::SentenceCat;
+    use crate::tables::sentence::SentenceCat;
     use core::cmp;
 
     // Describe a parsed part of source string as described in this table:
@@ -111,7 +111,7 @@ mod fwd {
         if parts[idx] == StatePart::ClosePlus { idx -= 1 }
 
         if parts[idx] == StatePart::ATerm {
-            use tables::sentence as se;
+            use crate::tables::sentence as se;
 
             for next_char in ahead.chars() {
                 //( ¬(OLetter | Upper | Lower | ParaSep | SATerm) )* Lower
@@ -176,7 +176,7 @@ mod fwd {
 
         #[inline]
         fn next(&mut self) -> Option<usize> {
-            use tables::sentence as se;
+            use crate::tables::sentence as se;
 
             for next_char in self.string[self.pos..].chars() {
                 let position_before = self.pos;
@@ -331,7 +331,7 @@ pub fn new_sentence_bound_indices<'a>(source: &'a str) -> USentenceBoundIndices<
 #[inline]
 pub fn new_unicode_sentences<'b>(s: &'b str) -> UnicodeSentences<'b> {
     use super::UnicodeSegmentation;
-    use tables::util::is_alphanumeric;
+    use crate::tables::util::is_alphanumeric;
 
     fn has_alphanumeric(s: &&str) -> bool { s.chars().any(|c| is_alphanumeric(c)) }
     let has_alphanumeric: fn(&&str) -> bool = has_alphanumeric; // coerce to fn pointer
diff --git a/src/tables.rs b/src/tables.rs
index 7062e36..6d09ea2 100644
--- a/src/tables.rs
+++ b/src/tables.rs
@@ -30,7 +30,7 @@ pub mod util {
     #[inline]
     fn is_alphabetic(c: char) -> bool {
         match c {
-            'a' ... 'z' | 'A' ... 'Z' => true,
+            'a' ..= 'z' | 'A' ..= 'Z' => true,
             c if c > '' => super::derived_property::Alphabetic(c),
             _ => false,
         }
@@ -39,7 +39,7 @@ pub mod util {
     #[inline]
     fn is_numeric(c: char) -> bool {
         match c {
-            '0' ... '9' => true,
+            '0' ..= '9' => true,
             c if c > '' => super::general_category::N(c),
             _ => false,
         }
@@ -352,7 +352,6 @@ pub mod grapheme {
     }
 
     fn bsearch_range_value_table(c: char, r: &'static [(char, char, GraphemeCat)]) -> (u32, u32, GraphemeCat) {
-        use core;
         use core::cmp::Ordering::{Equal, Less, Greater};
         match r.binary_search_by(|&(lo, hi, _)| {
             if lo <= c && c <= hi { Equal }
@@ -1003,7 +1002,6 @@ pub mod word {
     }
 
     fn bsearch_range_value_table(c: char, r: &'static [(char, char, WordCat)]) -> (u32, u32, WordCat) {
-        use core;
         use core::cmp::Ordering::{Equal, Less, Greater};
         match r.binary_search_by(|&(lo, hi, _)| {
             if lo <= c && c <= hi { Equal }
@@ -1479,7 +1477,6 @@ pub mod emoji {
     }
 
     fn bsearch_range_value_table(c: char, r: &'static [(char, char, EmojiCat)]) -> (u32, u32, EmojiCat) {
-        use core;
         use core::cmp::Ordering::{Equal, Less, Greater};
         match r.binary_search_by(|&(lo, hi, _)| {
             if lo <= c && c <= hi { Equal }
@@ -1583,7 +1580,6 @@ pub mod sentence {
     }
 
     fn bsearch_range_value_table(c: char, r: &'static [(char, char, SentenceCat)]) -> (u32, u32, SentenceCat) {
-        use core;
         use core::cmp::Ordering::{Equal, Less, Greater};
         match r.binary_search_by(|&(lo, hi, _)| {
             if lo <= c && c <= hi { Equal }
diff --git a/src/test.rs b/src/test.rs
index 75b77c5..ae74c64 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -14,7 +14,7 @@ use std::prelude::v1::*;
 
 #[test]
 fn test_graphemes() {
-    use testdata::{TEST_SAME, TEST_DIFF};
+    use crate::testdata::{TEST_SAME, TEST_DIFF};
 
     pub const EXTRA_DIFF: &'static [(&'static str,
                                      &'static [&'static str],
@@ -88,7 +88,7 @@ fn test_graphemes() {
 
 #[test]
 fn test_words() {
-    use testdata::TEST_WORD;
+    use crate::testdata::TEST_WORD;
 
     // Unicode's official tests don't really test longer chains of flag emoji
     // TODO This could be improved with more tests like flag emoji with interspersed Extend chars and ZWJ
@@ -144,7 +144,7 @@ fn test_words() {
 
 #[test]
 fn test_sentences() {
-    use testdata::TEST_SENTENCE;
+    use crate::testdata::TEST_SENTENCE;
 
     for &(s, w) in TEST_SENTENCE.iter() {
         macro_rules! assert_ {
diff --git a/src/word.rs b/src/word.rs
index 179d122..5cfde0d 100644
--- a/src/word.rs
+++ b/src/word.rs
@@ -11,7 +11,7 @@
 use core::cmp;
 use core::iter::Filter;
 
-use tables::word::WordCat;
+use crate::tables::word::WordCat;
 
 /// An iterator over the substrings of a string which, after splitting the string on
 /// [word boundaries](http://www.unicode.org/reports/tr29/#Word_Boundaries),
@@ -40,6 +40,34 @@ impl<'a> DoubleEndedIterator for UnicodeWords<'a> {
     fn next_back(&mut self) -> Option<&'a str> { self.inner.next_back() }
 }
 
+/// An iterator over the substrings of a string which, after splitting the string on
+/// [word boundaries](http://www.unicode.org/reports/tr29/#Word_Boundaries),
+/// contain any characters with the
+/// [Alphabetic](http://unicode.org/reports/tr44/#Alphabetic)
+/// property, or with
+/// [General_Category=Number](http://unicode.org/reports/tr44/#General_Category_Values).
+/// This iterator also provides the byte offsets for each substring.
+///
+/// This struct is created by the [`unicode_word_indices`] method on the [`UnicodeSegmentation`] trait. See
+/// its documentation for more.
+///
+/// [`unicode_word_indices`]: trait.UnicodeSegmentation.html#tymethod.unicode_word_indices
+/// [`UnicodeSegmentation`]: trait.UnicodeSegmentation.html
+pub struct UnicodeWordIndices<'a> {
+    inner: Filter<UWordBoundIndices<'a>, fn(&(usize, &str)) -> bool>,
+}
+
+impl<'a> Iterator for UnicodeWordIndices<'a> {
+    type Item = (usize, &'a str);
+
+    #[inline]
+    fn next(&mut self) -> Option<(usize, &'a str)> { self.inner.next() }
+}
+impl<'a> DoubleEndedIterator for UnicodeWordIndices<'a> {
+    #[inline]
+    fn next_back(&mut self) -> Option<(usize, &'a str)> { self.inner.next_back() }
+}
+
 /// External iterator for a string's
 /// [word boundaries](http://www.unicode.org/reports/tr29/#Word_Boundaries).
 ///
@@ -142,7 +170,7 @@ enum RegionalState {
 }
 
 fn is_emoji(ch: char) -> bool {
-    use tables::emoji;
+    use crate::tables::emoji;
     emoji::emoji_category(ch).2 == emoji::EmojiCat::EC_Extended_Pictographic
 }
 
@@ -159,7 +187,7 @@ impl<'a> Iterator for UWordBounds<'a> {
     fn next(&mut self) -> Option<&'a str> {
         use self::UWordBoundsState::*;
         use self::FormatExtendType::*;
-        use tables::word as wd;
+        use crate::tables::word as wd;
         if self.string.len() == 0 {
             return None;
         }
@@ -172,14 +200,13 @@ impl<'a> Iterator for UWordBounds<'a> {
         let mut cat = wd::WC_Any;
         let mut savecat = wd::WC_Any;
 
-        // Whether or not the previous category was ZWJ
-        // ZWJs get collapsed, so this handles precedence of WB3c over WB4
-        let mut prev_zwj;
         // If extend/format/zwj were skipped. Handles precedence of WB3d over WB4
         let mut skipped_format_extend = false;
         for (curr, ch) in self.string.char_indices() {
             idx = curr;
-            prev_zwj = cat == wd::WC_ZWJ;
+            // Whether or not the previous category was ZWJ
+            // ZWJs get collapsed, so this handles precedence of WB3c over WB4
+            let prev_zwj = cat == wd::WC_ZWJ;
             // if there's a category cached, grab it
             cat = match self.cat {
                 None => wd::word_category(ch).2,
@@ -386,7 +413,7 @@ impl<'a> DoubleEndedIterator for UWordBounds<'a> {
     fn next_back(&mut self) -> Option<&'a str> {
         use self::UWordBoundsState::*;
         use self::FormatExtendType::*;
-        use tables::word as wd;
+        use crate::tables::word as wd;
         if self.string.len() == 0 {
             return None;
         }
@@ -638,7 +665,7 @@ impl<'a> UWordBounds<'a> {
 
     #[inline]
     fn get_next_cat(&self, idx: usize) -> Option<WordCat> {
-        use tables::word as wd;
+        use crate::tables::word as wd;
         let nidx = idx + self.string[idx..].chars().next().unwrap().len_utf8();
         if nidx < self.string.len() {
             let nch = self.string[nidx..].chars().next().unwrap();
@@ -650,7 +677,7 @@ impl<'a> UWordBounds<'a> {
 
     #[inline]
     fn get_prev_cat(&self, idx: usize) -> Option<WordCat> {
-        use tables::word as wd;
+        use crate::tables::word as wd;
         if idx > 0 {
             let nch = self.string[..idx].chars().next_back().unwrap();
             Some(wd::word_category(nch).2)
@@ -671,12 +698,22 @@ pub fn new_word_bound_indices<'b>(s: &'b str) -> UWordBoundIndices<'b> {
 }
 
 #[inline]
+fn has_alphanumeric(s: &&str) -> bool {
+    use crate::tables::util::is_alphanumeric;
+
+    s.chars().any(|c| is_alphanumeric(c))
+}
+
+#[inline]
 pub fn new_unicode_words<'b>(s: &'b str) -> UnicodeWords<'b> {
     use super::UnicodeSegmentation;
-    use tables::util::is_alphanumeric;
-
-    fn has_alphanumeric(s: &&str) -> bool { s.chars().any(|c| is_alphanumeric(c)) }
-    let has_alphanumeric: fn(&&str) -> bool = has_alphanumeric; // coerce to fn pointer
 
     UnicodeWords { inner: s.split_word_bounds().filter(has_alphanumeric) }
 }
+
+#[inline]
+pub fn new_unicode_word_indices<'b>(s: &'b str) -> UnicodeWordIndices<'b> {
+    use super::UnicodeSegmentation;
+
+    UnicodeWordIndices { inner: s.split_word_bound_indices().filter(|(_, c)| has_alphanumeric(c)) }
+}