diff --git a/src/main.rs b/src/main.rs
index 7793f0f..8c9a944 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,30 +5,42 @@ use std::env;
 use std::process::Command;
 use std::{fs, str};
 
-// parse the config to this
+/// Configuration for swayout.
 #[derive(Serialize, Deserialize, Debug)]
-struct Rules {
+struct Config {
+    /// Monitor name is independent of output name. It can be anything.
     monitors: HashMap<String, Monitor>,
-    // Map of layout name to : map of monitor name to output config
+    /// Definition of layouts: a map of the layout name to the outputs.
+    /// The outputs is a map of the monitor name (in `monitors`) to the configuration
+    /// of that monitor for this layout.
+    /// Available outputs that do not match a monitor in the map are disabled.
     layouts: HashMap<String, HashMap<String, OutputConfig>>,
 }
+/// Defines a monitor by make, model, and serial.
 #[derive(Serialize, Deserialize, Debug)]
 struct Monitor {
     make: String,
     model: String,
     serial: String,
 }
+/// Configuration for an enabled output.
 #[derive(Serialize, Deserialize, Debug)]
 struct OutputConfig {
+    /// mode. See man 5 sway-output
     mode: String,
+    /// scale. See man 5 sway-output
     scale: String,
+    /// x value for position. See man 5 sway-output
     x: u16,
+    /// y value for position. See man 5 sway-output
     y: u16,
+    /// transform. See man 5 sway-output
     transform: String,
 }
 
-// parse output of swaymsg -t get_outputs to this
+/// An output, as returned by `swaymsg -t get_outputs`.
 struct Output {
+    /// output name, according to sway
     name: String,
     make: String,
     model: String,
@@ -48,9 +60,8 @@ fn main() {
     }
 }
 
-/// Get all outputs currently available
+/// Get all outputs currently available, according to `swaymsg -t get_outputs`.
 fn get_outputs() -> Vec<Output> {
-    // call `swaymsg -t get_outputs` to get outputs
     let output = Command::new("swaymsg")
         .arg("-t")
         .arg("get_outputs")
@@ -82,7 +93,7 @@ fn get_outputs() -> Vec<Output> {
 }
 
 /// Parse the mode from the output JSON into a string suitable for the mode param for sway-output.
-/// This will go into OutputConfig.mode
+/// This will go into `OutputConfig.mode`.
 fn get_mode(output: &Value) -> String {
     if let Value::Array(modes) = &output["modes"] {
         if let Some(mode) = modes.first() {
@@ -101,15 +112,16 @@ fn get_mode(output: &Value) -> String {
     }
 }
 
-/// Get the rules from ~/.config/swayout/config.toml
-fn get_rules() -> Rules {
+/// Get a `Config` from ~/.config/swayout/config.toml.
+/// (It really uses XDG config dirs.)
+fn get_config() -> Config {
     let xdg_dirs = xdg::BaseDirectories::with_prefix("swayout").unwrap();
     if let Some(path) = xdg_dirs.find_config_file("config.toml") {
         let toml = fs::read_to_string(path).expect("error reading file");
         toml::from_str(&toml).expect("toml parse error")
     } else {
         // no config files, use an empty rules
-        Rules {
+        Config {
             monitors: HashMap::new(),
             layouts: HashMap::new(),
         }
@@ -118,17 +130,16 @@ fn get_rules() -> Rules {
 
 /// Determine the available layout names.
 /// Return one layout for each layout defined in the configuration file
-/// (for which all outputs are available),
-/// one for each monitor defined in the configuration file
-/// (for using just that monitor),
+/// for which all outputs are available,
+/// one for each monitor defined in the configuration file (for using just that monitor),
 /// and one for each available output that is not a configured monitor (for using just that output).
 fn get_layouts() -> Vec<String> {
     let available_outputs = get_outputs();
-    let rules = get_rules();
+    let rules = get_config();
 
     let mut layout_names: Vec<String> = Vec::new();
 
-    // Get the names of monitors that are available (that match a current output)
+    // Get the names of monitors that are available (that match an available output)
     let available_monitor_names:Vec<&String> = rules.monitors.iter()
         .filter(|(_monitor_name,monitor)|
             available_outputs.iter().any(|output|
@@ -175,9 +186,10 @@ fn print_layout_names() {
 }
 
 /// Apply the specified layout.
-/// layout_name may be the name of a layout rule, the name of a monitor, or the name of an output.
+/// layout_name may be the name of a layout in the config, the name of a monitor,
+/// or the name of an output.
 fn apply_layout(layout_name: &String) {
-    let rules = get_rules();
+    let rules = get_config();
     let outputs = get_outputs();
 
     // Map of output name to config for all outputs to enable.
@@ -192,7 +204,6 @@ fn apply_layout(layout_name: &String) {
             let monitor = &rules.monitors[monitor_name];
 
             // find the output for the monitor to get the output name.
-            // (You can allegedly use "<make> <model> <serial>" instead of output name.)
             let output_opt = outputs.iter().find(|output| {
                 output.make == monitor.make
                     && output.model == monitor.model
@@ -210,8 +221,7 @@ fn apply_layout(layout_name: &String) {
         if let Some(monitor) = rules.monitors.get(layout_name) {
             // It is a monitor name. Find the matching output...
             if let Some(output) = outputs.iter().find(|output| {
-                output.make == monitor.make
-                    && output.model == monitor.model
+                output.make == monitor.make && output.model == monitor.model
                     && output.serial == monitor.serial
             }) {
                 output_config_map.insert(&output.name, &output.output_config);
@@ -234,12 +244,13 @@ fn apply_layout(layout_name: &String) {
 
 /// Apply the specified outputs. Enable all outputs in [outputs], disable others.
 fn apply_outputs(all_outputs: &Vec<Output>, outputs: &HashMap<&String, &OutputConfig>) {
-    let mut cmd = Command::new("swaymsg");
 
-    // enabled first, then disabled.
-    // That way if some work before an error, you at least have one output enabled.
+    // set enabled outputs first, then set disabled outputs.
+    // That way if some work before an error, you have at least one output enabled.
 
+    // for outputs to be enabled: map of output name to config
     let mut enabled: HashMap<&String,&OutputConfig> = HashMap::new();
+    // for outputs to be disabled: output names
     let mut disabled: Vec<&String> = Vec::new();
 
     all_outputs.iter().for_each(|output| {
@@ -250,6 +261,7 @@ fn apply_outputs(all_outputs: &Vec<Output>, outputs: &HashMap<&String, &OutputCo
         }
     });
 
+    let mut cmd = Command::new("swaymsg");
     enabled.iter().for_each(|(output_name,output_config)| {
         cmd.arg("output");
         cmd.arg(&output_name);
@@ -273,6 +285,7 @@ fn apply_outputs(all_outputs: &Vec<Output>, outputs: &HashMap<&String, &OutputCo
         cmd.arg(",");
     });
 
+    // print what we are about to do.
     cmd.get_args()
         .for_each(|arg| print!("{} ", arg.to_str().unwrap()));