feat: Add support for RPROMPT (right prompt) (#3026)

Adds support for zsh, fish, and elvish.

Co-authored-by: Matan Kushner <hello@matchai.dev>

docs/advanced-config/README.md

@@ -85,6 +85,37 @@ function set_win_title(){
 starship_precmd_user_func="set_win_title"
 ```
 
+## Enable Right Prompt
+
+Some shells support a right prompt which renders on the same line as the input. Starship can
+set the content of the right prompt using the `right_format` option. Any module that can be used
+in `format` is also supported in `right_format`. The `$all` variable will only contain modules
+not explicitly used in either `format` or `right_format`.
+
+Note: The right prompt is a single line following the input location. To right align modules above
+the input line in a multi-line prompt, see the [fill module](/config/#fill).
+
+`right_format` is currently supported for the following shells: elvish, fish, zsh.
+
+### Example
+
+```toml
+# ~/.config/starship.toml
+
+# A minimal left prompt
+format = """$character"""
+
+# move the rest of the prompt to the right
+right_format = """$all"""
+```
+
+Produces a prompt like the following:
+
+```
+▶                                   starship on  rprompt [!] is 📦 v0.57.0 via 🦀 v1.54.0 took 17s
+```
+
+
 ## Style Strings
 
 Style strings are a list of words, separated by whitespace. The words are not case sensitive (i.e. `bold` and `BoLd` are considered the same string). Each word can be one of the following:

docs/config/README.md

@@ -151,12 +151,14 @@ This is the list of prompt-wide configuration options.
 
 ### Options
 
-| Option            | Default                        | Description                                                  |
+| Option            | Default                         | Description                                                      |
-| ----------------- | ------------------------------ | ------------------------------------------------------------ |
+| ----------------- | ------------------------------- | ---------------------------------------------------------------- |
-| `format`          | [link](#default-prompt-format) | Configure the format of the prompt.                          |
+| `format`          | [link](#default-prompt-format)  | Configure the format of the prompt.                              |
-| `scan_timeout`    | `30`                           | Timeout for starship to scan files (in milliseconds).        |
+| `right_format`    | `""`                            | See [Enable Right Prompt](/advanced-config/#enable-right-prompt) |
-| `command_timeout` | `500`                          | Timeout for commands executed by starship (in milliseconds). |
+| `scan_timeout`    | `30`                            | Timeout for starship to scan files (in milliseconds).            |
-| `add_newline`     | `true`                         | Inserts blank line between shell prompts.                    |
+| `command_timeout` | `500`                           | Timeout for commands executed by starship (in milliseconds).     |
+| `add_newline`     | `true`                          | Inserts blank line between shell prompts.                        |
+
 
 ### Example
 
@@ -247,6 +249,14 @@ $shell\
 $character"""
 ```
 
+If you just want to extend the default format, you can use `$all`;
+modules you explicitly add to the format will not be duplicated. Eg.
+
+```toml
+# Move the directory to the second line
+format="$all$directory$character"
+```
+
 ## AWS
 
 The `aws` module shows the current AWS region and profile. This is based on

src/configs/starship_root.rs

@@ -7,6 +7,7 @@ use std::cmp::Ordering;
 #[derive(Clone, Serialize)]
 pub struct StarshipRootConfig<'a> {
     pub format: &'a str,
+    pub right_format: &'a str,
     pub scan_timeout: u64,
     pub command_timeout: u64,
     pub add_newline: bool,
@@ -90,6 +91,7 @@ impl<'a> Default for StarshipRootConfig<'a> {
     fn default() -> Self {
         StarshipRootConfig {
             format: "$all",
+            right_format: "",
             scan_timeout: 30,
             command_timeout: 500,
             add_newline: true,
@@ -102,6 +104,7 @@ impl<'a> ModuleConfig<'a> for StarshipRootConfig<'a> {
         if let toml::Value::Table(config) = config {
             config.iter().for_each(|(k, v)| match k.as_str() {
                 "format" => self.format.load_config(v),
+                "right_format" => self.right_format.load_config(v),
                 "scan_timeout" => self.scan_timeout.load_config(v),
                 "command_timeout" => self.command_timeout.load_config(v),
                 "add_newline" => self.add_newline.load_config(v),
@@ -115,6 +118,7 @@ impl<'a> ModuleConfig<'a> for StarshipRootConfig<'a> {
                         let did_you_mean = &[
                             // Root options
                             "format",
+                            "right_format",
                             "scan_timeout",
                             "command_timeout",
                             "add_newline",

src/context.rs

@@ -46,6 +46,9 @@ pub struct Context<'a> {
     /// The shell the user is assumed to be running
     pub shell: Shell,
 
+    /// Construct the right prompt instead of the left prompt
+    pub right: bool,
+
     /// A HashMap of environment variable mocks
     #[cfg(test)]
     pub env: HashMap<&'a str, String>,
@@ -120,6 +123,8 @@ impl<'a> Context<'a> {
 
         let cmd_timeout = Duration::from_millis(config.get_root_config().command_timeout);
 
+        let right = arguments.is_present("right");
+
         Context {
             config,
             properties,
@@ -129,6 +134,7 @@ impl<'a> Context<'a> {
             dir_contents: OnceCell::new(),
             repo: OnceCell::new(),
             shell,
+            right,
             #[cfg(test)]
             env: HashMap::new(),
             #[cfg(test)]

src/formatter/string_formatter.rs

@@ -86,6 +86,15 @@ impl<'a> StringFormatter<'a> {
         })
     }
 
+    /// A StringFormatter that does no formatting, parse just returns the raw text
+    pub fn raw(text: &'a str) -> Self {
+        Self {
+            format: vec![FormatElement::Text(text.into())],
+            variables: BTreeMap::new(),
+            style_variables: BTreeMap::new(),
+        }
+    }
+
     /// Maps variable name to its value
     ///
     /// You should provide a function or closure that accepts the variable name `name: &str` as a

src/init/starship.elv

@@ -4,6 +4,7 @@ set-env STARSHIP_SESSION_KEY (::STARSHIP:: session)
 # Define Hooks
 local:cmd-start-time = 0
 local:cmd-end-time = 0
+local:cmd-duration = 0
 
 fn starship-after-readline-hook [line]{
     cmd-start-time = (::STARSHIP:: time)
@@ -11,6 +12,7 @@ fn starship-after-readline-hook [line]{
 
 fn starship-before-readline-hook {
     cmd-end-time = (::STARSHIP:: time)
+    cmd-duration = (- $cmd-end-time $cmd-start-time)
 }
 
 # Install Hooks
@@ -25,9 +27,17 @@ edit:prompt = {
     if (== $cmd-start-time 0) {
         ::STARSHIP:: prompt --jobs=$num-bg-jobs
     } else {
-        ::STARSHIP:: prompt --jobs=$num-bg-jobs --cmd-duration=(- $cmd-end-time $cmd-start-time)
+        ::STARSHIP:: prompt --jobs=$num-bg-jobs --cmd-duration=$cmd-duration
     }
 }
 
-# Get rid of default rprompt
+edit:rprompt = {
-edit:rprompt = { }
+    # Note:
+    # Elvish does not appear to support exit status codes (--status)
+
+    if (== $cmd-start-time 0) {
+        ::STARSHIP:: prompt --right --jobs=$num-bg-jobs
+    } else {
+        ::STARSHIP:: prompt --right --jobs=$num-bg-jobs --cmd-duration=$cmd-duration
+    }
+}

src/init/starship.fish

@@ -8,7 +8,12 @@ function fish_prompt
     set STARSHIP_CMD_STATUS $status
     # Account for changes in variable name between v2.7 and v3.0
     set STARSHIP_DURATION "$CMD_DURATION$cmd_duration"
-    ::STARSHIP:: prompt --status=$STARSHIP_CMD_STATUS --pipestatus=$pipestatus --keymap=$STARSHIP_KEYMAP --cmd-duration=$STARSHIP_DURATION --jobs=(count (jobs -p))
+    set STARSHIP_JOBS (count (jobs -p))
+    ::STARSHIP:: prompt --status=$STARSHIP_CMD_STATUS --pipestatus=$pipestatus --keymap=$STARSHIP_KEYMAP --cmd-duration=$STARSHIP_DURATION --jobs=$STARSHIP_JOBS
+end
+
+function fish_right_prompt
+    ::STARSHIP:: prompt --right --status=$STARSHIP_CMD_STATUS --pipestatus=$pipestatus --keymap=$STARSHIP_KEYMAP --cmd-duration=$STARSHIP_DURATION --jobs=$STARSHIP_JOBS
 end
 
 # Disable virtualenv prompt, it breaks starship

src/init/starship.zsh

@@ -92,3 +92,4 @@ VIRTUAL_ENV_DISABLE_PROMPT=1
 
 setopt promptsubst
 PROMPT='$(::STARSHIP:: prompt --keymap="$KEYMAP" --status="$STARSHIP_CMD_STATUS" --pipestatus ${STARSHIP_PIPE_STATUS[@]} --cmd-duration="$STARSHIP_DURATION" --jobs="$STARSHIP_JOBS_COUNT")'
+RPROMPT='$(::STARSHIP:: prompt --right --keymap="$KEYMAP" --status="$STARSHIP_CMD_STATUS" --pipestatus ${STARSHIP_PIPE_STATUS[@]} --cmd-duration="$STARSHIP_DURATION" --jobs="$STARSHIP_JOBS_COUNT")'

src/main.rs

@@ -99,6 +99,11 @@ fn main() {
         .subcommand(
             SubCommand::with_name("prompt")
                 .about("Prints the full starship prompt")
+                .arg(
+                    Arg::with_name("right")
+                        .long("right")
+                        .help("Print the right prompt (instead of the standard left prompt)"),
+                )
                 .arg(&status_code_arg)
                 .arg(&pipestatus_arg)
                 .arg(&path_arg)

src/print.rs

@@ -79,18 +79,12 @@ pub fn get_prompt(context: Context) -> String {
         buf.push_str("\x1b[J"); // An ASCII control code to clear screen
     }
 
-    let formatter = if let Ok(formatter) = StringFormatter::new(config.format) {
+    let (formatter, modules) = load_formatter_and_modules(&context);
-        formatter
+
-    } else {
-        log::error!("Error parsing `format`");
-        buf.push('>');
-        return buf;
-    };
-    let modules = formatter.get_variables();
     let formatter = formatter.map_variables_to_segments(|module| {
-        // Make $all display all modules
+        // Make $all display all modules not explicitly referenced
         if module == "all" {
-            Some(Ok(PROMPT_ORDER
+            Some(Ok(all_modules_uniq(&modules)
                 .par_iter()
                 .flat_map(|module| {
                     handle_module(module, &context, &modules)
@@ -124,6 +118,11 @@ pub fn get_prompt(context: Context) -> String {
     }
     write!(buf, "{}", ANSIStrings(&module_strings)).unwrap();
 
+    if context.right {
+        // right prompts generally do not allow newlines
+        buf = buf.replace('\n', "");
+    }
+
     // escape \n and ! characters for tcsh
     if let Shell::Tcsh = context.shell {
         buf = buf.replace('!', "\\!");
@@ -288,20 +287,13 @@ pub fn explain(args: ArgMatches) {
 fn compute_modules<'a>(context: &'a Context) -> Vec<Module<'a>> {
     let mut prompt_order: Vec<Module<'a>> = Vec::new();
 
-    let config = context.config.get_root_config();
+    let (_formatter, modules) = load_formatter_and_modules(context);
-    let formatter = if let Ok(formatter) = StringFormatter::new(config.format) {
-        formatter
-    } else {
-        log::error!("Error parsing `format`");
-        return Vec::new();
-    };
-    let modules = formatter.get_variables();
 
     for module in &modules {
         // Manually add all modules if `$all` is encountered
         if module == "all" {
-            for module in PROMPT_ORDER {
+            for module in all_modules_uniq(&modules) {
-                let modules = handle_module(module, context, &modules);
+                let modules = handle_module(&module, context, &modules);
                 prompt_order.extend(modules);
             }
         } else {
@@ -403,3 +395,68 @@ pub fn format_duration(duration: &Duration) -> String {
         format!("{:?}ms", &milis)
     }
 }
+
+/// Return the modules from $all that are not already in the list
+fn all_modules_uniq(module_list: &BTreeSet<String>) -> Vec<String> {
+    let mut prompt_order: Vec<String> = Vec::new();
+    for module in PROMPT_ORDER.iter() {
+        if !module_list.contains(*module) {
+            prompt_order.push(String::from(*module))
+        }
+    }
+
+    prompt_order
+}
+
+/// Load the correct formatter for the context (ie left prompt or right prompt)
+/// and the list of all modules used in a format string
+fn load_formatter_and_modules<'a>(context: &'a Context) -> (StringFormatter<'a>, BTreeSet<String>) {
+    let config = context.config.get_root_config();
+
+    let lformatter = StringFormatter::new(config.format);
+    let rformatter = StringFormatter::new(config.right_format);
+    if lformatter.is_err() {
+        log::error!("Error parsing `format`")
+    }
+    if rformatter.is_err() {
+        log::error!("Error parsing `right_format`")
+    }
+
+    match (lformatter, rformatter) {
+        (Ok(lf), Ok(rf)) => {
+            let mut modules: BTreeSet<String> = BTreeSet::new();
+            modules.extend(lf.get_variables());
+            modules.extend(rf.get_variables());
+            if context.right {
+                (rf, modules)
+            } else {
+                (lf, modules)
+            }
+        }
+        _ => (StringFormatter::raw(">"), BTreeSet::new()),
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::config::StarshipConfig;
+    use crate::test::default_context;
+
+    #[test]
+    fn right_prompt() {
+        let mut context = default_context();
+        context.config = StarshipConfig {
+            config: Some(toml::toml! {
+                right_format="$character"
+                [character]
+                format=">\n>"
+            }),
+        };
+        context.right = true;
+
+        let expected = String::from(">>"); // should strip new lines
+        let actual = get_prompt(context);
+        assert_eq!(expected, actual);
+    }
+}

src/test/mod.rs

@@ -31,6 +31,17 @@ static LOGGER: Lazy<()> = Lazy::new(|| {
     log::set_boxed_logger(Box::new(logger)).unwrap();
 });
 
+pub fn default_context() -> Context<'static> {
+    let mut context = Context::new_with_shell_and_path(
+        clap::ArgMatches::default(),
+        Shell::Unknown,
+        PathBuf::new(),
+        PathBuf::new(),
+    );
+    context.config = StarshipConfig { config: None };
+    context
+}
+
 /// Render a specific starship module by name
 pub struct ModuleRenderer<'a> {
     name: &'a str,
@@ -43,13 +54,7 @@ impl<'a> ModuleRenderer<'a> {
         // Start logger
         Lazy::force(&LOGGER);
 
-        let mut context = Context::new_with_shell_and_path(
+        let context = default_context();
-            clap::ArgMatches::default(),
-            Shell::Unknown,
-            PathBuf::new(),
-            PathBuf::new(),
-        );
-        context.config = StarshipConfig { config: None };
 
         Self { name, context }
     }