docs: commit the example config the binary prints

README.md

@@ -7,3 +7,12 @@ DAWless / headless looping software for the Novation launchpad X.
 ```bash
 just run
 ```
+
+## Configuring
+
+```bash
+cp example.free-loop.toml free-loop.toml
+```
+
+Every setting is shown at its default. `free-loop.toml` is untracked; without one the
+default devices are used and no window opens.

crates/app/src/config.rs

@@ -402,6 +402,16 @@ mod tests {
         assert_eq!(config.engine.segment_pool, 2_048);
     }
 
+    #[test]
+    fn the_committed_example_is_the_one_the_binary_prints() {
+        // Compiled in: a missing file is a build error, not a failing test.
+        let committed = include_str!("../../../example.free-loop.toml");
+        assert_eq!(
+            committed, EXAMPLE,
+            "example.free-loop.toml has drifted from --print-config"
+        );
+    }
+
     #[test]
     fn the_example_file_parses_and_matches_the_defaults() {
         let config = Config::parse(EXAMPLE).unwrap();

example.free-loop.toml

@@ -0,0 +1,50 @@
+# Free Loop configuration. Every setting shown at its default.
+
+[audio]
+# Substrings of the device names. Omit to use the system default devices.
+# input_device = "Scarlett"
+# output_device = "Scarlett"
+
+# Omit to take the device's preference.
+# sample_rate = 48000
+# buffer_frames = 256
+# channels = 2
+
+# The device input channel your instrument is in. Omit for the first stereo pair.
+# A Scarlett Solo's instrument jack is channel 1.
+# input_channel = 1
+
+# Blocks of capture buffered before playback starts consuming. More is safer, later.
+cushion_blocks = 2
+
+# Round-trip latency to compensate for, in frames. Omit to measure it from the driver,
+# which is right for almost every rig. Set it only if a driver reports badly.
+# capture_offset_frames = 512
+
+# Whether losing a device freezes the transport. Off carries on as soon as it is back.
+pause_on_disconnect = true
+
+[transport]
+tempo = 120.0
+beats_per_bar = 4
+beat_unit = 4
+# Whether launching a clip plays it from its start. Off drops into whatever part of it the
+# transport has reached, which keeps every loop locked to the same grid.
+restart_clips = false
+
+[engine]
+# About 1.4 s of stereo audio and half a megabyte each, shared across every pad. Allocated at
+# startup, so this is resident memory: 2048 is roughly 46 minutes for just over a gigabyte.
+# The ceiling on a whole session: loaded audio reserves the same capacity as recorded audio,
+# so lowering this can leave a session already on disk too large to load.
+segment_pool = 2048
+# Frames a level takes to travel the full gain range. 5 ms at 48 kHz.
+declick_frames = 240
+
+[click]
+enabled = true
+level = 0.35
+
+[gui]
+# Open a window with an emulated Launchpad X, usable with or without the hardware.
+enabled = false