feat: add support for elvish shell (#1725)

* feat: add support for elvish shell

* improve doc

* elvish 0.15 is out

* fix example init

* update systax for 0.15 stable

* udpate second init example too

* remove warning from swift module

* add warning to status module docs

* prefix elvish version with v

8 files changed, 80 insertions, 1 deletions

diff --git a/README.md b/README.md
index 868beaffe..b04db86f4 100644
--- a/README.md
+++ b/README.md
@@ -224,6 +224,17 @@ shown below. Can't see yours? Have a look at the [extra platform instructions](h
    eval $(starship init ion)
    ```
 
+   #### Elvish
+
+   **Warning** Only elvish v0.15 or higher is supported.
+   Add the following to the end of `~/.elvish/rc.elv`:
+
+   ```sh
+   # ~/.elvish/rc.elv
+
+   eval (starship init elvish)
+   ```
+
 ## 🤝 Contributing
 
 We are always looking for contributors of **all skill levels**! If you're looking to ease your way into the project, try out a [good first issue](https://github.com/starship/starship/labels/🌱%20good%20first%20issue).
diff --git a/docs/README.md b/docs/README.md
index c3022b298..5fdedb9cf 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -101,3 +101,17 @@ description: Starship is the minimal, blazing fast, and extremely customizable p
 
    eval $(starship init ion)
    ```
+   #### Elvish
+
+   ::: warning
+   Only elvish v0.15 or higher is supported.
+   :::
+
+   Add the following to the end of `~/.elvish/rc.elv`:
+
+   ```sh
+   # ~/.elvish/rc.elv
+
+   eval (starship init elvish)
+   ```
+
diff --git a/docs/config/README.md b/docs/config/README.md
index 7a1b8a68d..790f23488 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -388,6 +388,10 @@ can do this in two ways:
 
 By default it only changes color. If you also want to change it's shape take a
 look at [this example](#with-custom-error-shape).
+ 
+::: warning
+`error_symbol` is not supported on elvish shell.
+:::
 
 ### Options
 
@@ -2263,6 +2267,10 @@ To enable it, set `disabled` to `false` in your configuration file.
 
 :::
 
+::: warning
+This module is not supported on elvish shell.
+:::
+
 ### Options
 
 | Option                    | Default                     | Description                                            |
diff --git a/src/bug_report.rs b/src/bug_report.rs
index 983e4319c..261c7be59 100644
--- a/src/bug_report.rs
+++ b/src/bug_report.rs
@@ -203,6 +203,7 @@ fn get_config_path(shell: &str) -> Option<PathBuf> {
                 }
             }
             "zsh" => Some(".zshrc"),
+            "elvish" => Some(".elvish/rc.elv"),
             _ => None,
         }
         .map(|path| home_dir.join(path))
diff --git a/src/context.rs b/src/context.rs
index 7b0986bf6..293f1bdf6 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -208,6 +208,7 @@ impl<'a> Context<'a> {
             "ion" => Shell::Ion,
             "powershell" => Shell::PowerShell,
             "zsh" => Shell::Zsh,
+            "elvish" => Shell::Elvish,
             _ => Shell::Unknown,
         }
     }
@@ -426,6 +427,7 @@ pub enum Shell {
     Ion,
     PowerShell,
     Zsh,
+    Elvish,
     Unknown,
 }
 
diff --git a/src/init/mod.rs b/src/init/mod.rs
index f80e8aedc..e8ff73ce2 100644
--- a/src/init/mod.rs
+++ b/src/init/mod.rs
@@ -166,6 +166,13 @@ fi"#,
             let script = format!("eval $({} init ion --print-full-init)", starship.sprint()?);
             Some(script)
         }
+        Some("elvish") => {
+            let script = format!(
+                "eval ({} init elvish --print-full-init | slurp)",
+                starship.sprint_posix()?
+            );
+            Some(script)
+        }
         None => {
             println!(
                 "Invalid shell name provided: {}\\n\
@@ -204,6 +211,7 @@ pub fn init_main(shell_name: &str) -> io::Result<()> {
         "fish" => print_script(FISH_INIT, &starship_path.sprint_posix()?),
         "powershell" => print_script(PWSH_INIT, &starship_path.sprint()?),
         "ion" => print_script(ION_INIT, &starship_path.sprint()?),
+        "elvish" => print_script(ELVISH_INIT, &starship_path.sprint_posix()?),
         _ => {
             println!(
                 "printf \"Shell name detection failed on phase two init.\\n\
@@ -245,3 +253,5 @@ const FISH_INIT: &str = include_str!("starship.fish");
 const PWSH_INIT: &str = include_str!("starship.ps1");
 
 const ION_INIT: &str = include_str!("starship.ion");
+
+const ELVISH_INIT: &str = include_str!("starship.elv");
diff --git a/src/init/starship.elv b/src/init/starship.elv
new file mode 100644
index 000000000..1b84632a8
--- /dev/null
+++ b/src/init/starship.elv
@@ -0,0 +1,33 @@
+set-env STARSHIP_SHELL "elvish"
+set-env STARSHIP_SESSION_KEY (::STARSHIP:: session)
+
+# Define Hooks
+local:cmd-start-time = 0
+local:cmd-end-time = 0
+
+fn starship-after-readline-hook [line]{
+    cmd-start-time = (::STARSHIP:: time)
+}
+
+fn starship-before-readline-hook {
+    cmd-end-time = (::STARSHIP:: time)
+}
+
+# Install Hooks
+edit:after-readline = [ $@edit:after-readline $starship-after-readline-hook~ ]
+edit:before-readline = [ $@edit:before-readline $starship-before-readline-hook~ ]
+
+# Install starship
+edit:prompt = {
+    # Note:
+    # Elvish does not appear to support exit status codes (--status)
+
+    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)
+    }
+}
+
+# Get rid of default rprompt
+edit:rprompt = { }
diff --git a/src/main.rs b/src/main.rs
index bbaa20fb4..b0b0a6cff 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -31,7 +31,7 @@ fn main() {
     let shell_arg = Arg::with_name("shell")
         .value_name("SHELL")
         .help(
-            "The name of the currently running shell\nCurrently supported options: bash, zsh, fish, powershell, ion",
+            "The name of the currently running shell\nCurrently supported options: bash, zsh, fish, powershell, ion, elvish",
         )
         .required(true);