Update organisation and documentHEADmaster

8 files changed, 384 insertions, 203 deletions

diff --git a/build.rs b/build.rs
index 46c31e3..18c690a 100644
--- a/build.rs
+++ b/build.rs
@@ -41,6 +41,7 @@ fn main() {
             .blacklist_item("true_")
             .blacklist_item("false_")
             .blacklist_item("__bool_true_false_are_defined")
+            .blacklist_function("tprintf")
             .blacklist_function("lgw_addf")
             .generate()
             .expect("Error generating bindings using bindgen");
diff --git a/src/core.rs b/src/core.rs
new file mode 100644
index 0000000..9e67722
--- /dev/null
+++ b/src/core.rs
@@ -0,0 +1,292 @@
+use std::char;
+use std::io;
+use std::marker::PhantomData;
+use std::sync::atomic::{AtomicBool, Ordering};
+
+use crate::bindings;
+use crate::util;
+
+pub const KEY_TAB: i32 = bindings::KEY_TAB as i32;
+pub const KEY_LF: i32 = bindings::KEY_LF as i32;
+pub const KEY_CR: i32 = bindings::KEY_CR as i32;
+pub const KEY_ESC: i32 = bindings::KEY_ESC as i32;
+pub const KEY_BACKSPACE: i32 = bindings::KEY_BACKSPACE as i32;
+
+pub const KEY_RIGHT: i32 = bindings::KEY_RIGHT as i32;
+pub const KEY_UP: i32 = bindings::KEY_UP as i32;
+pub const KEY_LEFT: i32 = bindings::KEY_LEFT as i32;
+pub const KEY_DOWN: i32 = bindings::KEY_DOWN as i32;
+pub const KEY_PAGEUP: i32 = bindings::KEY_PAGEUP as i32;
+pub const KEY_PAGEDOWN: i32 = bindings::KEY_PAGEDOWN as i32;
+pub const KEY_DELETE: i32 = bindings::KEY_DELETE as i32;
+pub const KEY_SHIFTTAB: i32 = bindings::KEY_SHIFTTAB as i32;
+
+/// Modifier combinator.
+pub const KEY_CTRL: i32 = bindings::KEY_CTRL as i32;
+/// Modifier combinator.
+pub const KEY_SHIFT: i32 = bindings::KEY_SHIFT as i32;
+/// Modifier combinator.
+pub const KEY_ALT: i32 = bindings::KEY_ALT as i32;
+/// Modifier combinator.
+pub const KEY_CTRLALT: i32 = bindings::KEY_CTRLALT as i32;
+/// Modifier combinator.
+pub const KEY_CTRLSHIFT: i32 = bindings::KEY_CTRLSHIFT as i32;
+
+/// A style descriptor for a cell on the screen.
+#[derive(Debug, Copy, Clone)]
+pub struct Style {
+    /// The foreground color; valid values are 0, 1, ..., 7 (the eight ANSI
+    /// colors) and 9 (the default color).
+    pub fg: u8,
+
+    /// The background color; valid values are 0, 1, ..., 7 (the eight ANSI
+    /// colors) and 9 (the default color).
+    pub bg: u8,
+
+    /// Whether the character in the cell should be printed bold. If this is
+    /// enabled, the terminal generally uses the bright version of the
+    /// foreground color instead of the normal version. Therefore, there are
+    /// effectively 16, not 8, foreground colors (in addition to the default
+    /// color, 9).
+    pub bold: bool,
+
+    /// Whether to display an underline.
+    pub ul: bool
+}
+
+/// RAII struct for keyboard-input initialization
+///
+/// Only one instance of this struct can be active at a time. Attempting to
+/// create a second instance will panic.
+pub struct Keyboard {
+    _phantom: PhantomData<*mut u8>,
+}
+
+static KEYBOARD_REFCOUNT: AtomicBool = AtomicBool::new(false);
+
+impl Keyboard {
+    /// Grab the keyboard, i.e. enable raw mode.
+    ///
+    /// This disables automatic printing of typed characters (echo), and allows
+    /// reading a single character even when a newline has not yet been
+    /// entered.
+    ///
+    /// If `nosigkeys` is true, interrupt keycodes like ctrl-C, ctrl-\ and
+    /// ctrl-Z will no longer be handled by the shell but will be available to
+    /// be read using `get_key()` just like the other keys.
+    pub fn grab(nosigkeys: bool) -> Self {
+        let prev = KEYBOARD_REFCOUNT.compare_and_swap(
+                        false, true, Ordering::SeqCst);
+        if prev {
+            panic!("Can only hold one Keyboard struct at a time!");
+        }
+
+        unsafe { bindings::initkeyboard(nosigkeys); }
+        Self { _phantom: PhantomData }
+    }
+
+    /// Explicitly release the keyboard.
+    ///
+    /// This prevents further use of the Keyboard functionality and
+    /// simultaneously forces its lifetime to extend until this call, delaying
+    /// deinitialization of the keyboard until this call.
+    pub fn end(self) {}
+
+    // None on EOF, otherwise a combination of the KEY_* constants
+    pub fn get_key(&self) -> io::Result<Option<i32>> {
+        match unsafe { bindings::tgetkey() } {
+            -2 => Err(io::Error::last_os_error()),
+            -1 => Ok(None),
+            value => Ok(Some(value)),
+        }
+    }
+
+    pub fn get_line(&self) -> Option<String> {
+        let ptr = unsafe { bindings::tgetline() };
+        if ptr.is_null() {
+            None
+        } else {
+            unsafe { Some(util::string_from_utf8_charp(ptr)) }
+        }
+    }
+}
+
+impl Drop for Keyboard {
+    fn drop(&mut self) {
+        let prev = KEYBOARD_REFCOUNT.compare_and_swap(
+                        true, false, Ordering::SeqCst);
+        if !prev {
+            panic!("Internal: No Keyboard was held on Drop of a Keyboard?");
+        }
+
+        unsafe { bindings::endkeyboard(); }
+    }
+}
+
+/// RAII struct for screen-drawing initialization
+///
+/// Only one instance of this struct can be active at a time. Attempting to
+/// create a second instance will panic.
+pub struct Screen<'a> {
+    _keyboard: &'a Keyboard,
+}
+
+static SCREEN_REFCOUNT: AtomicBool = AtomicBool::new(false);
+
+impl<'a> Screen<'a> {
+    /// Grab the screen, i.e. switch to the alternative screen and allocate draw
+    /// buffers.
+    ///
+    /// This function takes and stores a Keyboard reference to ensure that the
+    /// keyboard is initialized while the screen is grabbed.
+    pub fn grab<'b: 'a>(keyboard: &'b Keyboard) -> Self {
+        let prev = SCREEN_REFCOUNT.compare_and_swap(
+                        false, true, Ordering::SeqCst);
+        if prev {
+            panic!("Can only hold one Screen struct at a time!");
+        }
+
+        unsafe { bindings::initscreen(); }
+        Self { _keyboard: keyboard }
+    }
+
+    pub fn end(self) {}
+
+    /// Install ctrl-L redraw handler.
+    ///
+    /// If the argument is true, then upon reading ctrl-L in
+    /// `Keyboard::get_key()`, a full redraw is issued, and the the call blocks
+    /// for the next key. Note that if the user only types ctrl-L, this means
+    /// that `get_key` may block while you don't expect it.
+    pub fn install_cl_handler(&self, install: bool) {
+        unsafe { bindings::installCLhandler(install); }
+    }
+
+    /// Install redraw handler.
+    ///
+    /// The argument indicates whether the redraw is a full redraw. The handler
+    /// is called before the redraw is performed. Please do not trigger redraws
+    /// from within the handler.
+    pub fn on_redraw(&self, handler: extern "C" fn(full_redraw: bool)) {
+        unsafe { bindings::installredrawhandler(Some(handler)); }
+    }
+
+    pub fn clear(&self) {
+        unsafe { bindings::clearscreen(); }
+    }
+
+    /// Update style state.
+    ///
+    /// This modifies the style for the characters printed from now on. Note
+    /// that this does not write anything to the terminal.
+    pub fn set_style(&self, style: Style) {
+        let sty = bindings::Style {
+            fg: style.fg as i32,
+            bg: style.bg as i32,
+            bold: style.bold,
+            ul: style.ul,
+        };
+        unsafe { bindings::setstyle(&sty as *const bindings::Style); }
+    }
+
+    /// Update partial style state. see `set_style()`.
+    pub fn set_fg(&self, fg: u8) {
+        unsafe { bindings::setfg(fg as i32); }
+    }
+
+    /// Update partial style state. see `set_style()`.
+    pub fn set_bg(&self, bg: u8) {
+        unsafe { bindings::setbg(bg as i32); }
+    }
+
+    /// Update partial style state. see `set_style()`.
+    pub fn set_bold(&self, bold: bool) {
+        unsafe { bindings::setbold(bold); }
+    }
+
+    /// Update partial style state. see `set_style()`.
+    pub fn set_ul(&self, ul: bool) {
+        unsafe { bindings::setul(ul); }
+    }
+
+    pub fn putc(&self, c: char) {
+        unsafe { bindings::tputc(c as i32); }
+    }
+
+    /// Newlines ('\n') return to the column on which printing started.
+    pub fn print(&self, s: &str) {
+        unsafe { bindings::tprint(s.as_bytes().as_ptr() as *const i8); }
+    }
+
+    pub fn fill_rect(&self, lefttop: (u32, u32), size: (u32, u32), c: char) {
+        unsafe { bindings::fillrect(
+                    lefttop.0 as i32, lefttop.1 as i32,
+                    size.0 as i32, size.1 as i32,
+                    c as i32); }
+    }
+
+    pub fn redraw(&self) {
+        unsafe { bindings::redraw(); }
+    }
+
+    pub fn redraw_full(&self) {
+        unsafe { bindings::redrawfull(); }
+    }
+
+    /// Scrolls a rectangle on the screen by a signed number of lines.
+    pub fn scroll_term(&self, lefttop: (u32, u32), size: (u32, u32), amount: i32) {
+        unsafe { bindings::scrollterm(
+                    lefttop.0 as i32, lefttop.1 as i32,
+                    size.0 as i32, size.1 as i32,
+                    amount); }
+    }
+
+    pub fn get_buffer_char(&self, pos: (u32, u32)) -> char {
+        unsafe {
+            char::from_u32(
+                bindings::getbufferchar(pos.0 as i32, pos.1 as i32) as u32
+            ).unwrap()
+        }
+    }
+
+    /// Updates state; does not actually move the cursor yet (use `redraw()`).
+    pub fn move_to(&self, pos: (u32, u32)) {
+        unsafe { bindings::moveto(pos.0 as i32, pos.1 as i32); }
+    }
+
+    /// Save the (internal) cursor position on a stack.
+    pub fn push_cursor(&self) {
+        unsafe { bindings::pushcursor(); }
+    }
+
+    /// Pop the (internal) cursor position from the stack.
+    pub fn pop_cursor(&self) {
+        unsafe { bindings::popcursor(); }
+    }
+
+    /// Takes effect immediately!
+    pub fn cursor_visible(&self, visible: bool) {
+        unsafe { bindings::cursorvisible(visible); }
+    }
+}
+
+impl<'a> Drop for Screen<'a> {
+    fn drop(&mut self) {
+        let prev = SCREEN_REFCOUNT.compare_and_swap(
+                        true, false, Ordering::SeqCst);
+        if !prev {
+            panic!("Internal: No Screen was held on Drop of a Screen?");
+        }
+
+        unsafe { bindings::endscreen(); }
+    }
+}
+
+pub fn get_term_size() -> (u32, u32) {
+    let sz = unsafe { bindings::gettermsize() };
+    (sz.w as u32, sz.h as u32)
+}
+
+pub fn bel() {
+    unsafe { bindings::bel(); }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 7a17a0f..b092b85 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,183 +1,31 @@
-use std::char;
-use std::io;
+//! This crate contains bindings to the C library [termio][1]. Most functions
+//! wrapped are methods on the `Screen` or `Keyboard` structs, while others take
+//! one of these structs as an argument. This organisation ensures that e.g. the
+//! screen can only be redrawn while the double-buffered screen is actually
+//! active, and that keys can only be read from the input while the input stream
+//! is actually in raw mode.
+//!
+//! The `widgets` submodule contains the built-in widget modules in termio.
+//!
+//! All callbacks are `extern "C"` functions, and thus do not accept generic
+//! `Fn` instances. This is due to a limitation of the original termio API.
+//!
+//! In this crate, terminal screen positions and sizes are represented using a
+//! tuple `(x, y): (u32, u32)`. Positions are zero-based.
+//!
+//! The `KEY_` constants describe the return values from `Keyboard::get_key()`.
+//! To create key combinations, e.g. ctrl-A, use addition, e.g. `KEY_CTRL +
+//! 'A'`.
+//!
+//! **Please be aware that to get anything on the screen, you need to call
+//! `redraw()`.**
+//!
+//! [1]: https://github.com/tomsmeding/termio
 
 mod bindings;
 mod util;
-pub mod widgets;
-
-// #[cfg(test)]
-// mod tests {
-//     #[test]
-//     fn it_works() {
-//         assert_eq!(2 + 2, 4);
-//     }
-// }
-
-// All positions are represented using a tuple (x, y): (u32, u32).
-// Positions are zero-based.
-
-pub const KEY_TAB: i32 = bindings::KEY_TAB as i32;
-pub const KEY_LF: i32 = bindings::KEY_LF as i32;
-pub const KEY_CR: i32 = bindings::KEY_CR as i32;
-pub const KEY_ESC: i32 = bindings::KEY_ESC as i32;
-pub const KEY_BACKSPACE: i32 = bindings::KEY_BACKSPACE as i32;
-
-pub const KEY_RIGHT: i32 = bindings::KEY_RIGHT as i32;
-pub const KEY_UP: i32 = bindings::KEY_UP as i32;
-pub const KEY_LEFT: i32 = bindings::KEY_LEFT as i32;
-pub const KEY_DOWN: i32 = bindings::KEY_DOWN as i32;
-pub const KEY_PAGEUP: i32 = bindings::KEY_PAGEUP as i32;
-pub const KEY_PAGEDOWN: i32 = bindings::KEY_PAGEDOWN as i32;
-pub const KEY_DELETE: i32 = bindings::KEY_DELETE as i32;
-pub const KEY_SHIFTTAB: i32 = bindings::KEY_SHIFTTAB as i32;
-
-pub const KEY_CTRL: i32 = bindings::KEY_CTRL as i32;
-pub const KEY_SHIFT: i32 = bindings::KEY_SHIFT as i32;
-pub const KEY_ALT: i32 = bindings::KEY_ALT as i32;
-pub const KEY_CTRLALT: i32 = bindings::KEY_CTRLALT as i32;
-pub const KEY_CTRLSHIFT: i32 = bindings::KEY_CTRLSHIFT as i32;
-
-#[derive(Debug, Copy, Clone)]
-pub struct Style {
-    pub fg: u8,  // 0-7, 9
-    pub bg: u8,  // 0-7, 9
-    pub bold: bool,
-    pub ul: bool
-}
-
-pub fn init_keyboard(nosigkeys: bool) {
-    unsafe { bindings::initkeyboard(nosigkeys); }
-}
-
-pub fn end_keyboard() {
-    unsafe { bindings::endkeyboard(); }
-}
-
-pub fn init_screen() {
-    unsafe { bindings::initscreen(); }
-}
-
-pub fn end_screen() {
-    unsafe { bindings::endscreen(); }
-}
-
-pub fn install_cl_handler(install: bool) {
-    unsafe { bindings::installCLhandler(install); }
-}
-
-pub fn install_redraw_handler(handler: extern "C" fn(full_redraw: bool)) {
-    unsafe { bindings::installredrawhandler(Some(handler)); }
-}
-
-pub fn clear_screen() {
-    unsafe { bindings::clearscreen(); }
-}
-
-pub fn get_term_size() -> (u32, u32) {
-    let sz = unsafe { bindings::gettermsize() };
-    (sz.w as u32, sz.h as u32)
-}
-
-pub fn set_style(style: Style) {
-    let sty = bindings::Style {
-        fg: style.fg as i32,
-        bg: style.bg as i32,
-        bold: style.bold,
-        ul: style.ul,
-    };
-    unsafe { bindings::setstyle(&sty as *const bindings::Style); }
-}
-
-pub fn set_fg(fg: u8) {
-    unsafe { bindings::setfg(fg as i32); }
-}
 
-pub fn set_bg(bg: u8) {
-    unsafe { bindings::setbg(bg as i32); }
-}
-
-pub fn set_bold(bold: bool) {
-    unsafe { bindings::setbold(bold); }
-}
-
-pub fn set_ul(ul: bool) {
-    unsafe { bindings::setul(ul); }
-}
-
-pub fn putc(c: char) {
-    unsafe { bindings::tputc(c as i32); }
-}
-
-pub fn print(s: &str) {
-    unsafe { bindings::tprintf(
-                "%s".as_bytes().as_ptr() as *const i8,
-                s.as_bytes().as_ptr() as *const i8); }
-}
-
-pub fn fill_rect(lefttop: (u32, u32), size: (u32, u32), c: char) {
-    unsafe { bindings::fillrect(
-                lefttop.0 as i32, lefttop.1 as i32,
-                size.0 as i32, size.1 as i32,
-                c as i32); }
-}
-
-pub fn redraw() {
-    unsafe { bindings::redraw(); }
-}
-
-pub fn redraw_full() {
-    unsafe { bindings::redrawfull(); }
-}
-
-pub fn scroll_term(lefttop: (u32, u32), size: (u32, u32), c: char) {
-    unsafe { bindings::scrollterm(
-                lefttop.0 as i32, lefttop.1 as i32,
-                size.0 as i32, size.1 as i32,
-                c as i32); }
-}
-
-pub fn get_buffer_char(pos: (u32, u32)) -> char {
-    unsafe {
-        char::from_u32(
-            bindings::getbufferchar(pos.0 as i32, pos.1 as i32) as u32
-        ).unwrap()
-    }
-}
-
-pub fn move_to(pos: (u32, u32)) {
-    unsafe { bindings::moveto(pos.0 as i32, pos.1 as i32); }
-}
-
-pub fn push_cursor() {
-    unsafe { bindings::pushcursor(); }
-}
-
-pub fn pop_cursor() {
-    unsafe { bindings::popcursor(); }
-}
-
-pub fn bel() {
-    unsafe { bindings::bel(); }
-}
-
-pub fn cursor_visible(visible: bool) {
-    unsafe { bindings::cursorvisible(visible); }
-}
-
-// None on EOF, otherwise a combination of the KEY_* constants
-pub fn get_key() -> io::Result<Option<i32>> {
-    match unsafe { bindings::tgetkey() } {
-        -2 => Err(io::Error::last_os_error()),
-        -1 => Ok(None),
-        value => Ok(Some(value)),
-    }
-}
+mod core;
+pub mod widgets;
 
-pub fn get_line() -> Option<String> {
-    let ptr = unsafe { bindings::tgetline() };
-    if ptr.is_null() {
-        None
-    } else {
-        unsafe { Some(util::string_from_utf8_charp(ptr)) }
-    }
-}
+pub use crate::core::*;
diff --git a/src/widgets.rs b/src/widgets.rs
index d8c8e2e..fa79aab 100644
--- a/src/widgets.rs
+++ b/src/widgets.rs
@@ -1,3 +1,8 @@
+//! The built-in widgets in termio.
+//!
+//! The structures and functions for each of the widgets live in their
+//! respective submodules below.
+
 pub mod log;
 pub mod prompt;
 pub mod menu;
diff --git a/src/widgets/log.rs b/src/widgets/log.rs
index 8bd240a..4966cc0 100644
--- a/src/widgets/log.rs
+++ b/src/widgets/log.rs
@@ -1,27 +1,44 @@
+//! Logging events in a scrolling list.
+//!
+//! Events are logged in an upwards scrolled box that forgets about the events
+//! that move off-screen. The logger may optionally add timestamps to events.
+//!
+//! To create a log widget, make a `LogBuilder`, optionally modify properties,
+//! and then use its `create` method to create a `Log` object.
+
 use std::ptr;
 
 use crate::bindings;
+use crate::core::Screen;
 
 pub struct Log {
     ptr: *mut bindings::Logwidget,
 }
 
-pub struct LogBuilder<'a> {
+pub struct LogBuilder<'a, 'b> {
+    _screen: &'a Screen<'b>,
     lefttop: (u32, u32),
     size: (u32, u32),
     title: Option<&'a str>,
     timestamps: bool,
 }
 
-impl<'a> LogBuilder<'a> {
-    pub fn add_title<'s: 'a>(&'a mut self, title: &'s str)
-                -> &'a mut LogBuilder<'a> {
+impl<'a, 'b> LogBuilder<'a, 'b> {
+    pub fn new(screen: &'a Screen<'b>, lefttop: (u32, u32), size: (u32, u32)) -> Self {
+        LogBuilder {
+            _screen: screen,
+            lefttop, size,
+            title: None,
+            timestamps: false,
+        }
+    }
+
+    pub fn add_title<'s: 'a>(&mut self, title: &'s str) -> &mut Self {
         self.title = Some(title);
         self
     }
 
-    pub fn set_timestamps(&'a mut self, timestamps: bool)
-                -> &'a mut LogBuilder<'a> {
+    pub fn set_timestamps(&mut self, timestamps: bool) -> &mut Self {
         self.timestamps = timestamps;
         self
     }
@@ -43,14 +60,8 @@ impl<'a> LogBuilder<'a> {
 }
 
 impl Log {
-    pub fn new<'a>(lefttop: (u32, u32), size: (u32, u32)) -> LogBuilder<'a> {
-        LogBuilder {
-            lefttop, size,
-            title: None,
-            timestamps: false,
-        }
-    }
-
+    /// Called automatically; should only be needed if something else overwrote
+    /// the widget.
     pub fn redraw(&self) {
         unsafe { bindings::lgw_redraw(self.ptr); }
     }
diff --git a/src/widgets/menu.rs b/src/widgets/menu.rs
index fe899e3..f90e62b 100644
--- a/src/widgets/menu.rs
+++ b/src/widgets/menu.rs
@@ -1,3 +1,9 @@
+//! A selection menu.
+//!
+//! The configuration for a menu is encapsulated in a `Data` struct, which
+//! contains some number of `Item` structs which describe the individual items
+//! to be chosen between.
+
 use std::ffi::c_void;
 
 use crate::bindings;
@@ -46,10 +52,15 @@ impl Menu {
         }
     }
 
+    /// Called automatically; should only be needed if something else overwrote
+    /// the widget.
     pub fn redraw(&self) {
         unsafe { bindings::menu_redraw(self.ptr); }
     }
 
+    /// Process the given key in the context of the menu.
+    ///
+    /// The key should be a return value from `Keyboard::get_key()`.
     pub fn handle_key(&mut self, key: i32) -> KeyResult {
         match unsafe { bindings::menu_handlekey(self.ptr, key) } {
             bindings::Menukey_MENUKEY_HANDLED => KeyResult::Handled,
diff --git a/src/widgets/prompt.rs b/src/widgets/prompt.rs
index 0690840..31c8630 100644
--- a/src/widgets/prompt.rs
+++ b/src/widgets/prompt.rs
@@ -1,21 +1,36 @@
+//! A box for getting a line of text input.
+//!
+//! To create a prompt widget, make a `PromptBuilder`, optionally modify
+//! properties, and then use its `create` method to create a `Prompt` object.
+
 use std::ptr;
 
 use crate::bindings;
+use crate::core::Screen;
 use crate::util;
 
 pub struct Prompt {
     ptr: *mut bindings::Promptwidget,
 }
 
-pub struct PromptBuilder<'a> {
+pub struct PromptBuilder<'a, 'b> {
+    _screen: &'a Screen<'b>,
     lefttop: (u32, u32),
     width: u32,
     title: Option<&'a str>,
 }
 
-impl<'a> PromptBuilder<'a> {
-    pub fn add_title<'s: 'a>(&'a mut self, title: &'s str)
-                -> &'a mut PromptBuilder<'a> {
+impl<'a, 'b> PromptBuilder<'a, 'b> {
+    pub fn new(screen: &'a Screen<'b>, lefttop: (u32, u32), width: u32) -> Self {
+        PromptBuilder {
+            _screen: screen,
+            lefttop, width,
+            title: None,
+        }
+    }
+
+    pub fn add_title<'s: 'a>(&mut self, title: &'s str)
+                -> &mut Self {
         self.title = Some(title);
         self
     }
@@ -36,17 +51,15 @@ impl<'a> PromptBuilder<'a> {
 }
 
 impl Prompt {
-    pub fn new<'a>(lefttop: (u32, u32), width: u32) -> PromptBuilder<'a> {
-        PromptBuilder {
-            lefttop, width,
-            title: None,
-        }
-    }
-
+    /// Called automatically; should only be needed if something else overwrote
+    /// the widget.
     pub fn redraw(&self) {
         unsafe { bindings::prw_redraw(self.ptr); }
     }
 
+    /// Input string if <enter>, None otherwise.
+    ///
+    /// The key should be a return value from `Keyboard::get_key()`.
     pub fn handle_key(&mut self, key: i32) -> Option<String> {
         let ptr = unsafe { bindings::prw_handlekey(self.ptr, key) };
         if ptr.is_null() {
diff --git a/vendor/termio b/vendor/termio
-Subproject e2c2f93cd657ce9a40bcfd6c085328ac54e7a69
+Subproject 0f498cf54d8ecbfc81cf8b03ed2fcf3995b513f