feat: Implement PowerShell support (#470)

src/init/mod.rs

@@ -94,6 +94,21 @@ fi"#,
             );
             Some(script)
         }
+        Some("powershell") => {
+            // Explanation of syntax:
+            // &: Explicitly tells powershell to execute path with starship executable.
+            //
+            // @: multi-line stdout is returned as an array, but a single line or no lines
+            //    are returned as-is. @ ensures it's always an array.
+            //
+            // -join "`n": Joins the stdout array together as a string with newlines.
+            //             Powershell escapes with ` instead of \ thus `n translates to a newline.
+            let script = format!(
+                "Invoke-Expression (@(&\"{}\" init powershell --print-full-init) -join \"`n\")",
+                starship
+            );
+            Some(script)
+        }
         None => {
             println!(
                 "Invalid shell name provided: {}\\n\
@@ -130,6 +145,7 @@ pub fn init_main(shell_name: &str) -> io::Result<()> {
         "bash" => Some(BASH_INIT),
         "zsh" => Some(ZSH_INIT),
         "fish" => Some(FISH_INIT),
+        "powershell" => Some(PWSH_INIT),
         _ => {
             println!(
                 "printf \"Shell name detection failed on phase two init.\\n\
@@ -168,3 +184,5 @@ const BASH_INIT: &str = include_str!("starship.bash");
 const ZSH_INIT: &str = include_str!("starship.zsh");
 
 const FISH_INIT: &str = include_str!("starship.fish");
+
+const PWSH_INIT: &str = include_str!("starship.ps1");

src/init/starship.ps1

@@ -0,0 +1,23 @@
+#!/usr/bin/env pwsh
+
+# Starship assumes UTF-8
+[Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+function global:prompt {
+    $out = $null
+    # @ makes sure the result is an array even if single or no values are returned
+    $jobs = @(Get-Job | Where-Object { $_.State -eq 'Running' }).Count
+
+    if ($lastCmd = Get-History -Count 1) {
+        $duration = [math]::Round(($lastCmd.EndExecutionTime - $lastCmd.StartExecutionTime).TotalSeconds)
+        # & ensures the path is interpreted as something to execute
+        $out = @(&::STARSHIP:: prompt --status=$lastexitcode --jobs=$jobs --cmd-duration=$duration)
+    } else {
+        $out = @(&::STARSHIP:: prompt --status=$lastexitcode --jobs=$jobs)
+    }
+
+    # Convert stdout (array of lines) to expected return type string
+    # `n is an escaped newline
+    $out -join "`n"
+}
+
+$ENV:STARSHIP_SHELL = "powershell"

src/main.rs

@@ -34,7 +34,7 @@ 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",
+            "The name of the currently running shell\nCurrently supported options: bash, zsh, fish, powershell",
         )
         .required(true);
 

src/modules/battery.rs

@@ -8,6 +8,7 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let shell = std::env::var("STARSHIP_SHELL").unwrap_or_default();
     let percentage_char = match shell.as_str() {
         "zsh" => "%%", // % is an escape in zsh, see PROMPT in `man zshmisc`
+        "powershell" => "`%",
         _ => "%",
     };
 

src/modules/conda.rs

@@ -10,8 +10,8 @@ use crate::configs::conda::CondaConfig;
 /// Will display the Conda environment iff `$CONDA_DEFAULT_ENV` is set.
 pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     // Reference implementation: https://github.com/denysdovhan/spaceship-prompt/blob/master/sections/conda.zsh
-    let conda_env = env::var("CONDA_DEFAULT_ENV").ok()?;
-    if conda_env.is_empty() {
+    let conda_env = env::var("CONDA_DEFAULT_ENV").unwrap_or_else(|_| "".into());
+    if conda_env.trim().is_empty() {
         return None;
     }