tui: add pgup/pgdn and extract tui_keys

tui/src/tui_engine/tui_keys.rs

@@ -0,0 +1,90 @@
+use crate::*;
+
+pub struct KeyMatcher {
+    valid: bool,
+    key:   Option<KeyCode>,
+    mods:  KeyModifiers,
+}
+
+impl KeyMatcher {
+    pub fn new (token: impl AsRef<str>) -> Self {
+        let token = token.as_ref();
+        if token.len() < 2 {
+            Self { valid: false, key: None, mods: KeyModifiers::NONE }
+        } else if token.chars().next() != Some('@') {
+            Self { valid: false, key: None, mods: KeyModifiers::NONE }
+        } else {
+            Self { valid: true, key: None, mods: KeyModifiers::NONE }.next(&token[1..])
+        }
+    }
+    pub fn build (self) -> Option<Event> {
+        if self.valid && self.key.is_some() {
+            Some(Event::Key(KeyEvent::new(self.key.unwrap(), self.mods)))
+        } else {
+            None
+        }
+    }
+    fn next (mut self, token: &str) -> Self {
+        let mut tokens = token.split('-').peekable();
+        while let Some(token) = tokens.next() {
+            if tokens.peek().is_some() {
+                match token {
+                    "ctrl"  | "Ctrl"  | "c" | "C" => self.mods |= KeyModifiers::CONTROL,
+                    "alt"   | "Alt"   | "m" | "M" => self.mods |= KeyModifiers::ALT,
+                    "shift" | "Shift" | "s" | "S" => {
+                        self.mods |= KeyModifiers::SHIFT;
+                        // + TODO normalize character case, BackTab, etc.
+                    },
+                    _ => panic!("unknown modifier {token}"),
+                }
+            } else {
+                self.key = if token.len() == 1 {
+                    Some(KeyCode::Char(token.chars().next().unwrap()))
+                } else {
+                    Some(Self::named_key(token).unwrap_or_else(||panic!("unknown character {token}")))
+                }
+            }
+        }
+        self
+    }
+    fn named_key (token: &str) -> Option<KeyCode> {
+        use KeyCode::*;
+        Some(match token {
+            "up"                => Up,
+            "down"              => Down,
+            "left"              => Left,
+            "right"             => Right,
+            "esc"    | "escape" => Esc,
+            "enter"  | "return" => Enter,
+            "delete" | "del"    => Delete,
+            "tab"               => Tab,
+            "space"             => Char(' '),
+            "comma"             => Char(','),
+            "period"            => Char('.'),
+            "plus"              => Char('+'),
+            "minus" | "dash"    => Char('-'),
+            "equal" | "equals"  => Char('='),
+            "underscore"        => Char('_'),
+            "backtick"          => Char('`'),
+            "lt"                => Char('<'),
+            "gt"                => Char('>'),
+            "openbracket"       => Char('['),
+            "closebracket"      => Char(']'),
+            "pgup" | "pageup"   => PageUp,
+            "pgdn" | "pagedown" => PageDown, 
+            "f1"                => F(1),
+            "f2"                => F(2),
+            "f3"                => F(3),
+            "f4"                => F(4),
+            "f5"                => F(5),
+            "f6"                => F(6),
+            "f7"                => F(7),
+            "f8"                => F(8),
+            "f9"                => F(9),
+            "f10"               => F(10),
+            "f11"               => F(11),
+            "f12"               => F(12),
+            _ => return None,
+        })
+    }
+}