Add structopt dependency in version 0.3.7

This patch series replaces argparse with structopt in the argument
handling code. As a first step, we need structopt as a dependency.

Import subrepo structopt/:structopt at efbdda4753592e27bc430fb01f7b9650b2f3174d
Import subrepo bitflags/:bitflags at 30668016aca6bd3b02c766e8347e0b4080d4c296
Import subrepo clap/:clap at 784524f7eb193e35f81082cc69454c8c21b948f7
Import subrepo heck/:heck at 093d56fbf001e1506e56dbfa38631d99b1066df1
Import subrepo proc-macro-error/:proc-macro-error at 6c4cfe79a622c5de8ae68557993542be46eacae2
Import subrepo proc-macro2/:proc-macro2 at d5d48eddca4566e5438e8a2cbed4a74e049544de
Import subrepo quote/:quote at 727436c6c137b20f0f34dde5d8fda2679b9747ad
Import subrepo rustversion/:rustversion at 0c5663313516263059ce9059ef81fc7a1cf655ca
Import subrepo syn-mid/:syn-mid at 5d3d85414a9e6674e1857ec22a87b96e04a6851a
Import subrepo syn/:syn at e87c27e87f6f4ef8919d0372bdb056d53ef0d8f3
Import subrepo textwrap/:textwrap at abcd618beae3f74841032aa5b53c1086b0a57ca2
Import subrepo unicode-segmentation/:unicode-segmentation at 637c9874c4fe0c205ff27787faf150a40295c6c3
Import subrepo unicode-width/:unicode-width at 3033826f8bf05e82724140a981d5941e48fce393
Import subrepo unicode-xid/:unicode-xid at 4baae9fffb156ba229665b972a9cd5991787ceb7

13 files changed, 820 insertions, 0 deletions

diff --git a/heck/.gitignore b/heck/.gitignore
new file mode 100644
index 0000000..a9d37c5
--- /dev/null
+++ b/heck/.gitignore
@@ -0,0 +1,2 @@
+target
+Cargo.lock
diff --git a/heck/Cargo.toml b/heck/Cargo.toml
new file mode 100644
index 0000000..93b64e8
--- /dev/null
+++ b/heck/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+authors = ["Without Boats <woboats@gmail.com>"]
+name = "heck"
+version = "0.3.1"
+license = "MIT OR Apache-2.0"
+description = "heck is a case conversion library."
+homepage = "https://github.com/withoutboats/heck"
+repository = "https://github.com/withoutboats/heck"
+documentation = "https://docs.rs/heck"
+keywords = ["string", "case", "camel", "snake", "unicode"]
+readme = "README.md"
+
+[dependencies]
+unicode-segmentation = "1.2.0"
diff --git a/heck/LICENSE-APACHE b/heck/LICENSE-APACHE
new file mode 100644
index 0000000..16fe87b
--- /dev/null
+++ b/heck/LICENSE-APACHE
@@ -0,0 +1,201 @@
+                              Apache License
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+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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diff --git a/heck/LICENSE-MIT b/heck/LICENSE-MIT
new file mode 100644
index 0000000..e69282e
--- /dev/null
+++ b/heck/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2015 The Rust Project Developers
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/heck/README.md b/heck/README.md
new file mode 100644
index 0000000..cf32337
--- /dev/null
+++ b/heck/README.md
@@ -0,0 +1,56 @@
+# **heck** is a case conversion library
+
+!["I specifically requested the opposite of this."](https://github.com/withoutboats/heck/blob/master/no_step_on_snek.png)
+
+This library exists to provide case conversion between common cases like
+CamelCase and snake_case. It is intended to be unicode aware, internally
+consistent, and reasonably well performing.
+
+## Definition of a word boundary
+
+Word boundaries are defined as the "unicode words" defined in the
+`unicode_segmentation` library, as well as within those words in this manner:
+
+1. All underscore characters are considered word boundaries.
+2. If an uppercase character is followed by lowercase letters, a word boundary
+is considered to be just prior to that uppercase character.
+3. If multiple uppercase characters are consecutive, they are considered to be
+within a single word, except that the last will be part of the next word if it
+is followed by lowercase characters (see rule 2).
+
+That is, "HelloWorld" is segmented `Hello|World` whereas "XMLHttpRequest" is
+segmented `XML|Http|Request`.
+
+Characters not within words (such as spaces, punctuations, and underscores)
+are not included in the output string except as they are a part of the case
+being converted to. Multiple adjacent word boundaries (such as a series of
+underscores) are folded into one. ("hello__world" in snake case is therefore
+"hello_world", not the exact same string). Leading or trailing word boundary
+indicators are dropped, except insofar as CamelCase capitalizes the first word.
+
+### Cases contained in this library:
+
+1. CamelCase
+2. snake_case
+3. kebab-case
+4. SHOUTY_SNAKE_CASE
+5. mixedCase
+6. Title Case
+
+
+### Contributing
+
+PRs of additional well-established cases welcome.
+
+This library is a little bit opinionated (dropping punctuation, for example).
+If that doesn't fit your use case, I hope there is another crate that does. I
+would prefer **not** to receive PRs to make this behavior more configurable.
+
+Bug reports & fixes always welcome. :-)
+
+### License
+
+heck is distributed under the terms of both the MIT license and the
+Apache License (Version 2.0).
+
+See LICENSE-APACHE and LICENSE-MIT for details.
diff --git a/heck/no_step_on_snek.png b/heck/no_step_on_snek.png
new file mode 100644
index 0000000..8aff445
--- /dev/null
+++ b/heck/no_step_on_snek.png
diff --git a/heck/src/camel.rs b/heck/src/camel.rs
new file mode 100644
index 0000000..74bd741
--- /dev/null
+++ b/heck/src/camel.rs
@@ -0,0 +1,52 @@
+/// This trait defines a camel case conversion.
+///
+/// In CamelCase, word boundaries are indicated by capital letters, including
+/// the first word.
+///
+/// ## Example:
+///
+/// ```rust
+/// extern crate heck;
+/// fn main() {
+///     
+///     use heck::CamelCase;
+///
+///     let sentence = "We are not in the least afraid of ruins.";
+///     assert_eq!(sentence.to_camel_case(), "WeAreNotInTheLeastAfraidOfRuins");
+/// }
+/// ```
+pub trait CamelCase: ToOwned {
+    /// Convert this type to camel case.
+    fn to_camel_case(&self) -> Self::Owned;
+}
+
+impl CamelCase for str {
+    fn to_camel_case(&self) -> String {
+        ::transform(self, ::capitalize, |_| {})
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::CamelCase;
+
+    macro_rules! t {
+        ($t:ident : $s1:expr => $s2:expr) => {
+            #[test]
+            fn $t() {
+                assert_eq!($s1.to_camel_case(), $s2)
+            }
+        }
+    }
+
+    t!(test1: "CamelCase" => "CamelCase");
+    t!(test2: "This is Human case." => "ThisIsHumanCase");
+    t!(test3: "MixedUP_CamelCase, with some Spaces" => "MixedUpCamelCaseWithSomeSpaces");
+    t!(test4: "mixed_up_ snake_case, with some _spaces" => "MixedUpSnakeCaseWithSomeSpaces");
+    t!(test5: "kebab-case" => "KebabCase");
+    t!(test6: "SHOUTY_SNAKE_CASE" => "ShoutySnakeCase");
+    t!(test7: "snake_case" => "SnakeCase");
+    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "ThisContainsAllKindsOfWordBoundaries");
+    t!(test9: "XΣXΣ baffle" => "XσxςBaffle");
+    t!(test10: "XMLHttpRequest" => "XmlHttpRequest");
+}
diff --git a/heck/src/kebab.rs b/heck/src/kebab.rs
new file mode 100644
index 0000000..f81ba92
--- /dev/null
+++ b/heck/src/kebab.rs
@@ -0,0 +1,51 @@
+/// This trait defines a kebab case conversion.
+///
+/// In kebab-case, word boundaries are indicated by hyphens.
+///
+/// ## Example:
+///
+/// ```rust
+/// extern crate heck;
+/// fn main() {
+///     
+///     use heck::KebabCase;
+///
+///     let sentence = "We are going to inherit the earth.";
+///     assert_eq!(sentence.to_kebab_case(), "we-are-going-to-inherit-the-earth");
+/// }
+/// ```
+pub trait KebabCase: ToOwned {
+    /// Convert this type to kebab case.
+    fn to_kebab_case(&self) -> Self::Owned;
+}
+
+impl KebabCase for str {
+    fn to_kebab_case(&self) -> Self::Owned {
+        ::transform(self, ::lowercase, |s| s.push('-'))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::KebabCase;
+
+    macro_rules! t {
+        ($t:ident : $s1:expr => $s2:expr) => {
+            #[test]
+            fn $t() {
+                assert_eq!($s1.to_kebab_case(), $s2)
+            }
+        }
+    }
+
+    t!(test1: "CamelCase" => "camel-case");
+    t!(test2: "This is Human case." => "this-is-human-case");
+    t!(test3: "MixedUP CamelCase, with some Spaces" => "mixed-up-camel-case-with-some-spaces");
+    t!(test4: "mixed_up_ snake_case with some _spaces" => "mixed-up-snake-case-with-some-spaces");
+    t!(test5: "kebab-case" => "kebab-case");
+    t!(test6: "SHOUTY_SNAKE_CASE" => "shouty-snake-case");
+    t!(test7: "snake_case" => "snake-case");
+    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "this-contains-all-kinds-of-word-boundaries");
+    t!(test9: "XΣXΣ baffle" => "xσxς-baffle");
+    t!(test10: "XMLHttpRequest" => "xml-http-request");
+}
diff --git a/heck/src/lib.rs b/heck/src/lib.rs
new file mode 100644
index 0000000..c35ba34
--- /dev/null
+++ b/heck/src/lib.rs
@@ -0,0 +1,165 @@
+//! **heck** is a case conversion library.
+//!
+//! This library exists to provide case conversion between common cases like
+//! CamelCase and snake_case. It is intended to be unicode aware, internally,
+//! consistent, and reasonably well performing.
+//!
+//! ## Definition of a word boundary
+//!
+//! Word boundaries are defined as the "unicode words" defined in the
+//! `unicode_segmentation` library, as well as within those words in this manner:
+//!
+//! 1. All underscore characters are considered word boundaries.
+//! 2. If an uppercase character is followed by lowercase letters, a word boundary
+//! is considered to be just prior to that uppercase character.
+//! 3. If multiple uppercase characters are consecutive, they are considered to be
+//! within a single word, except that the last will be part of the next word if it
+//! is followed by lowercase characters (see rule 2).
+//!
+//! That is, "HelloWorld" is segmented `Hello|World` whereas "XMLHttpRequest" is
+//! segmented `XML|Http|Request`.
+//!
+//! Characters not within words (such as spaces, punctuations, and underscores)
+//! are not included in the output string except as they are a part of the case
+//! being converted to. Multiple adjacent word boundaries (such as a series of
+//! underscores) are folded into one. ("hello__world" in snake case is therefore
+//! "hello_world", not the exact same string). Leading or trailing word boundary
+//! indicators are dropped, except insofar as CamelCase capitalizes the first word.
+//!
+//! ### Cases contained in this library:
+//!
+//! 1. CamelCase
+//! 2. snake_case
+//! 3. kebab-case
+//! 4. SHOUTY_SNAKE_CASE
+//! 5. mixedCase
+//! 6. Title Case
+#![deny(missing_docs)]
+extern crate unicode_segmentation;
+
+mod camel;
+mod kebab;
+mod mixed;
+mod shouty_snake;
+mod snake;
+mod title;
+
+pub use camel::CamelCase;
+pub use kebab::KebabCase;
+pub use mixed::MixedCase;
+pub use shouty_snake::{ShoutySnakeCase, ShoutySnekCase};
+pub use snake::{SnakeCase, SnekCase};
+pub use title::TitleCase;
+
+use unicode_segmentation::UnicodeSegmentation;
+
+fn transform<F, G>(s: &str, with_word: F, boundary: G) -> String
+where
+    F: Fn(&str, &mut String),
+    G: Fn(&mut String)
+{
+
+    /// Tracks the current 'mode' of the transformation algorithm as it scans the input string.
+    ///
+    /// The mode is a tri-state which tracks the case of the last cased character of the current
+    /// word. If there is no cased character (either lowercase or uppercase) since the previous
+    /// word boundary, than the mode is `Boundary`. If the last cased character is lowercase, then
+    /// the mode is `Lowercase`. Othertherwise, the mode is `Uppercase`.
+    #[derive(Clone, Copy, PartialEq)]
+    enum WordMode {
+        /// There have been no lowercase or uppercase characters in the current word.
+        Boundary,
+        /// The previous cased character in the current word is lowercase.
+        Lowercase,
+        /// The previous cased character in the current word is uppercase.
+        Uppercase,
+    }
+
+    let mut out = String::new();
+    let mut first_word = true;
+
+    for word in s.unicode_words() {
+        let mut char_indices = word.char_indices().peekable();
+        let mut init = 0;
+        let mut mode = WordMode::Boundary;
+
+        while let Some((i, c)) = char_indices.next() {
+            // Skip underscore characters
+            if c == '_' {
+                if init == i { init += 1; }
+                continue
+            }
+
+            if let Some(&(next_i, next)) = char_indices.peek() {
+
+                // The mode including the current character, assuming the current character does
+                // not result in a word boundary.
+                let next_mode = if c.is_lowercase() {
+                    WordMode::Lowercase
+                } else if c.is_uppercase() {
+                    WordMode::Uppercase
+                } else {
+                    mode
+                };
+
+                // Word boundary after if next is underscore or current is
+                // not uppercase and next is uppercase
+                if next == '_' || (next_mode == WordMode::Lowercase && next.is_uppercase()) {
+                    if !first_word { boundary(&mut out); }
+                    with_word(&word[init..next_i], &mut out);
+                    first_word = false;
+                    init = next_i;
+                    mode = WordMode::Boundary;
+
+                // Otherwise if current and previous are uppercase and next
+                // is lowercase, word boundary before
+                } else if mode == WordMode::Uppercase && c.is_uppercase() && next.is_lowercase() {
+                    if !first_word { boundary(&mut out); }
+                    else { first_word = false; }
+                    with_word(&word[init..i], &mut out);
+                    init = i;
+                    mode = WordMode::Boundary;
+
+                // Otherwise no word boundary, just update the mode
+                } else {
+                    mode = next_mode;
+                }
+            } else {
+                // Collect trailing characters as a word
+                if !first_word { boundary(&mut out); }
+                else { first_word = false; }
+                with_word(&word[init..], &mut out);
+                break;
+            }
+        }
+    }
+
+    out
+}
+
+fn lowercase(s: &str, out: &mut String) {
+    let mut chars = s.chars().peekable();
+    while let Some(c) = chars.next() {
+        if c == 'Σ' && chars.peek().is_none() {
+            out.push('ς');
+        } else {
+            out.extend(c.to_lowercase());
+        }
+    }
+}
+
+fn uppercase(s: &str, out: &mut String ) {
+    for c in s.chars() {
+        out.extend(c.to_uppercase())
+    }
+}
+
+fn capitalize(s: &str, out: &mut String) {
+    let mut char_indices = s.char_indices();
+    if let Some((_, c)) = char_indices.next() {
+        out.extend(c.to_uppercase());
+        if let Some((i, _)) = char_indices.next() {
+            lowercase(&s[i..], out);
+        }
+    }
+}
diff --git a/heck/src/mixed.rs b/heck/src/mixed.rs
new file mode 100644
index 0000000..7736684
--- /dev/null
+++ b/heck/src/mixed.rs
@@ -0,0 +1,56 @@
+/// This trait defines a mixed case conversion.
+///
+/// In mixedCase, word boundaries are indicated by capital letters, excepting
+/// the first word.
+///
+/// ## Example:
+///
+/// ```rust
+/// extern crate heck;
+/// fn main() {
+///     
+///     use heck::MixedCase;
+///
+///     let sentence = "It is we who built these palaces and cities.";
+///     assert_eq!(sentence.to_mixed_case(), "itIsWeWhoBuiltThesePalacesAndCities");
+/// }
+/// ```
+pub trait MixedCase: ToOwned {
+    /// Convert this type to mixed case.
+    fn to_mixed_case(&self) -> Self::Owned;
+}
+
+impl MixedCase for str {
+    fn to_mixed_case(&self) -> String {
+        ::transform(self, |s, out| {
+            if out.is_empty() { ::lowercase(s, out); }
+            else { ::capitalize(s, out) }
+        }, |_| {})
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::MixedCase;
+
+    macro_rules! t {
+        ($t:ident : $s1:expr => $s2:expr) => {
+            #[test]
+            fn $t() {
+                assert_eq!($s1.to_mixed_case(), $s2)
+            }
+        }
+    }
+
+    t!(test1: "CamelCase" => "camelCase");
+    t!(test2: "This is Human case." => "thisIsHumanCase");
+    t!(test3: "MixedUP CamelCase, with some Spaces" => "mixedUpCamelCaseWithSomeSpaces");
+    t!(test4: "mixed_up_ snake_case, with some _spaces" => "mixedUpSnakeCaseWithSomeSpaces");
+    t!(test5: "kebab-case" => "kebabCase");
+    t!(test6: "SHOUTY_SNAKE_CASE" => "shoutySnakeCase");
+    t!(test7: "snake_case" => "snakeCase");
+    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "thisContainsAllKindsOfWordBoundaries");
+    t!(test9: "XΣXΣ baffle" => "xσxςBaffle");
+    t!(test10: "XMLHttpRequest" => "xmlHttpRequest");
+    // TODO unicode tests
+}
diff --git a/heck/src/shouty_snake.rs b/heck/src/shouty_snake.rs
new file mode 100644
index 0000000..0f846c3
--- /dev/null
+++ b/heck/src/shouty_snake.rs
@@ -0,0 +1,67 @@
+/// This trait defines a shouty snake case conversion.
+///
+/// In SHOUTY_SNAKE_CASE, word boundaries are indicated by underscores and all
+/// words are in uppercase.
+///
+/// ## Example:
+///
+/// ```rust
+/// extern crate heck;
+/// fn main() {
+///     
+///     use heck::ShoutySnakeCase;
+///
+///     let sentence = "That world is growing in this minute.";
+///     assert_eq!(sentence.to_shouty_snake_case(), "THAT_WORLD_IS_GROWING_IN_THIS_MINUTE");
+/// }
+/// ```
+pub trait ShoutySnakeCase: ToOwned {
+    /// Convert this type to shouty snake case.
+    fn to_shouty_snake_case(&self) -> Self::Owned;
+}
+
+/// Oh heck, ShoutySnekCase is an alias for ShoutySnakeCase. See ShoutySnakeCase for
+/// more documentation.
+pub trait ShoutySnekCase: ToOwned {
+    /// CONVERT THIS TYPE TO SNEK CASE.
+    #[allow(non_snake_case)]
+    fn TO_SHOUTY_SNEK_CASE(&self) -> Self::Owned;
+}
+
+impl<T: ?Sized + ShoutySnakeCase> ShoutySnekCase for T {
+    fn TO_SHOUTY_SNEK_CASE(&self) -> Self::Owned {
+        self.to_shouty_snake_case()
+    }
+}
+
+
+impl ShoutySnakeCase for str {
+    fn to_shouty_snake_case(&self) -> Self::Owned {
+        ::transform(self, ::uppercase, |s| s.push('_'))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::ShoutySnakeCase;
+
+    macro_rules! t {
+        ($t:ident : $s1:expr => $s2:expr) => {
+            #[test]
+            fn $t() {
+                assert_eq!($s1.to_shouty_snake_case(), $s2)
+            }
+        }
+    }
+
+    t!(test1: "CamelCase" => "CAMEL_CASE");
+    t!(test2: "This is Human case." => "THIS_IS_HUMAN_CASE");
+    t!(test3: "MixedUP CamelCase, with some Spaces" => "MIXED_UP_CAMEL_CASE_WITH_SOME_SPACES");
+    t!(test4: "mixed_up_snake_case with some _spaces" => "MIXED_UP_SNAKE_CASE_WITH_SOME_SPACES");
+    t!(test5: "kebab-case" => "KEBAB_CASE");
+    t!(test6: "SHOUTY_SNAKE_CASE" => "SHOUTY_SNAKE_CASE");
+    t!(test7: "snake_case" => "SNAKE_CASE");
+    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "THIS_CONTAINS_ALL_KINDS_OF_WORD_BOUNDARIES");
+    t!(test9: "XΣXΣ baffle" => "XΣXΣ_BAFFLE");
+    t!(test10: "XMLHttpRequest" => "XML_HTTP_REQUEST");
+}
diff --git a/heck/src/snake.rs b/heck/src/snake.rs
new file mode 100644
index 0000000..86c3756
--- /dev/null
+++ b/heck/src/snake.rs
@@ -0,0 +1,79 @@
+/// This trait defines a camel case conversion.
+///
+/// In snake_case, word boundaries are indicated by underscores.
+///
+/// ## Example:
+///
+/// ```rust
+/// extern crate heck;
+/// fn main() {
+///
+///     use heck::SnakeCase;
+///
+///     let sentence = "We carry a new world here, in our hearts.";
+///     assert_eq!(sentence.to_snake_case(), "we_carry_a_new_world_here_in_our_hearts");
+/// }
+/// ```
+pub trait SnakeCase: ToOwned {
+    /// Convert this type to snake case.
+    fn to_snake_case(&self) -> Self::Owned;
+}
+
+/// Oh heck, SnekCase is an alias for SnakeCase. See SnakeCase for
+/// more documentation.
+pub trait SnekCase: ToOwned {
+    /// Convert this type to snek case.
+    fn to_snek_case(&self) -> Self::Owned;
+}
+
+impl<T: ?Sized + SnakeCase> SnekCase for T {
+    fn to_snek_case(&self) -> Self::Owned {
+        self.to_snake_case()
+    }
+}
+
+impl SnakeCase for str {
+    fn to_snake_case(&self) -> String {
+        ::transform(self, ::lowercase, |s| s.push('_'))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::SnakeCase;
+
+    macro_rules! t {
+        ($t:ident : $s1:expr => $s2:expr) => {
+            #[test]
+            fn $t() {
+                assert_eq!($s1.to_snake_case(), $s2)
+            }
+        }
+    }
+
+    t!(test1: "CamelCase" => "camel_case");
+    t!(test2: "This is Human case." => "this_is_human_case");
+    t!(test3: "MixedUP CamelCase, with some Spaces" => "mixed_up_camel_case_with_some_spaces");
+    t!(test4: "mixed_up_ snake_case with some _spaces" => "mixed_up_snake_case_with_some_spaces");
+    t!(test5: "kebab-case" => "kebab_case");
+    t!(test6: "SHOUTY_SNAKE_CASE" => "shouty_snake_case");
+    t!(test7: "snake_case" => "snake_case");
+    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "this_contains_all_kinds_of_word_boundaries");
+    t!(test9: "XΣXΣ baffle" => "xσxς_baffle");
+    t!(test10: "XMLHttpRequest" => "xml_http_request");
+    t!(test11: "FIELD_NAME11" => "field_name11");
+    t!(test12: "99BOTTLES" => "99bottles");
+    t!(test13: "FieldNamE11" => "field_nam_e11");
+
+    t!(test14: "abc123def456" => "abc123def456");
+    t!(test16: "abc123DEF456" => "abc123_def456");
+    t!(test17: "abc123Def456" => "abc123_def456");
+    t!(test18: "abc123DEf456" => "abc123_d_ef456");
+    t!(test19: "ABC123def456" => "abc123def456");
+    t!(test20: "ABC123DEF456" => "abc123def456");
+    t!(test21: "ABC123Def456" => "abc123_def456");
+    t!(test22: "ABC123DEf456" => "abc123d_ef456");
+    t!(test23: "ABC123dEEf456FOO" => "abc123d_e_ef456_foo");
+    t!(test24: "abcDEF" => "abc_def");
+    t!(test25: "ABcDE" => "a_bc_de");
+}
diff --git a/heck/src/title.rs b/heck/src/title.rs
new file mode 100644
index 0000000..cb48302
--- /dev/null
+++ b/heck/src/title.rs
@@ -0,0 +1,52 @@
+/// This trait defines a title case conversion.
+///
+/// In Title Case, word boundaries are indicated by spaces, and every word is
+/// capitalized.
+///
+/// ## Example:
+///
+/// ```rust
+/// extern crate heck;
+/// fn main() {
+///     
+///     use heck::TitleCase;
+///
+///     let sentence = "We have always lived in slums and holes in the wall.";
+///     assert_eq!(sentence.to_title_case(), "We Have Always Lived In Slums And Holes In The Wall");
+/// }
+/// ```
+pub trait TitleCase: ToOwned {
+    /// Convert this type to title case.
+    fn to_title_case(&self) -> Self::Owned;
+}
+
+impl TitleCase for str {
+    fn to_title_case(&self) -> String {
+        ::transform(self, ::capitalize, |s| s.push(' '))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::TitleCase;
+
+    macro_rules! t {
+        ($t:ident : $s1:expr => $s2:expr) => {
+            #[test]
+            fn $t() {
+                assert_eq!($s1.to_title_case(), $s2)
+            }
+        }
+    }
+
+    t!(test1: "CamelCase" => "Camel Case");
+    t!(test2: "This is Human case." => "This Is Human Case");
+    t!(test3: "MixedUP CamelCase, with some Spaces" => "Mixed Up Camel Case With Some Spaces");
+    t!(test4: "mixed_up_ snake_case, with some _spaces" => "Mixed Up Snake Case With Some Spaces");
+    t!(test5: "kebab-case" => "Kebab Case");
+    t!(test6: "SHOUTY_SNAKE_CASE" => "Shouty Snake Case");
+    t!(test7: "snake_case" => "Snake Case");
+    t!(test8: "this-contains_ ALLKinds OfWord_Boundaries" => "This Contains All Kinds Of Word Boundaries");
+    t!(test9: "XΣXΣ baffle" => "Xσxς Baffle");
+    t!(test10: "XMLHttpRequest" => "Xml Http Request");
+}