Add the command tnew toggling whether only new cards should be shown.

README.md

@@ -68,8 +68,8 @@ You can then run `mkmu`, which crawls directories (and subdirectories) and
 compiles the TeX files using the `latexmk` build tool. The resulting files are
 placed in the `deck` directory.
 
-You can then `cd` into `deck` and run `mu`, which starts `mu`, entering into a
-shell-like problem that looks like this (run `help` to see list of commands):
+You can then run `mu` in the directory containing the `deck/` directory, which starts `mu`, entering
+into a shell-like problem that looks like this (run `help` to see list of commands):
 
     ——— card 'grassmanian' ———
     file:      grassmanian.pdf

backend/src/scheduler.rs

@@ -188,6 +188,11 @@ pub struct Scheduler {
     /// This is supposed to reflect the number of cards in `self.queue` whose scheduled time is
     /// prior to the current point in time.
     due: usize,
+    /// Should we prefer new cards?
+    ///
+    /// When this is set to `true`, the scheduler will yield cards from the new queue whenever
+    /// possible.
+    pub prefer_new: bool,
 }
 
 impl Scheduler {
@@ -244,6 +249,7 @@ impl Scheduler {
             current_card: !0,
             queue,
             due: 0,
+            prefer_new: false,
         };
 
         // Populate the new cards queue with the new cards from today, that are not studied yet.
@@ -323,8 +329,8 @@ impl Scheduler {
         let new = if self.new_queue.is_empty() {
             // There are no new cards to be introduced.
             false
-        } else if self.due == 0 {
-            // There are no due cards.
+        } else if self.due == 0 || self.prefer_new {
+            // There are no due cards, or new cards are preferred.
             true
         // Randomly choose between the new queue or the due cards. The ratio is chosen such
         // that the space between new cards is as wide as possible.

src/main.rs

@@ -28,7 +28,8 @@ hard, h  : Review the card as hard
 okay, o  : Review the card as okay
 good, g  : Review the card as good
 easy, e  : Review the card as easy
-post, p  : Postpone the card to tomorrow"#;
+post, p  : Postpone the card to tomorrow
+tnew, tn : Toggle whether new cards should be preferred"#;
 
 /// Formatter for durations.
 struct DurationFormatter(chrono::Duration);
@@ -123,9 +124,10 @@ impl<W: Write, R: io::BufRead> State<W, R> {
 
     /// Print the shell, that is, the text before the command input.
     pub fn print_shell(&mut self) -> Result<(), Error> {
-        write!(self.stdout, "D:{} N:{} {}>>{} ",
+        write!(self.stdout, "D:{} N:{}{} {}>>{} ",
             self.scheduler.due_cards(),
             self.scheduler.new_cards(),
+            if self.scheduler.prefer_new { "-" } else { "" },
             color::Fg(color::Red),
             color::Fg(color::Reset),
         )?;
@@ -168,6 +170,8 @@ impl<W: Write, R: io::BufRead> State<W, R> {
             "quit" | "q" => return Ok(false),
             // Print help screen.
             "help" | "he" => self.help()?,
+            // Toggle preference for new cards.
+            "tnew" | "tn" => self.scheduler.prefer_new ^= true,
             // Skip.
             "" => (),
             // Unknown command.