Add support for Lean 4's elan (#742)

src/config.rs

@@ -75,6 +75,7 @@ pub enum Step {
     Distrobox,
     DkpPacman,
     Dotnet,
+    Elan,
     Emacs,
     Firmware,
     Flatpak,

src/main.rs

@@ -342,6 +342,7 @@ fn run() -> Result<()> {
 
     // The following update function should be executed on all OSes.
     runner.execute(Step::Fossil, "fossil", || generic::run_fossil(&ctx))?;
+    runner.execute(Step::Elan, "elan", || generic::run_elan(&ctx))?;
     runner.execute(Step::Rustup, "rustup", || generic::run_rustup(&ctx))?;
     runner.execute(Step::Juliaup, "juliaup", || generic::run_juliaup(&ctx))?;
     runner.execute(Step::Dotnet, ".NET", || generic::run_dotnet_upgrade(&ctx))?;

src/steps/generic.rs

@@ -227,6 +227,17 @@ pub fn run_rustup(ctx: &ExecutionContext) -> Result<()> {
     ctx.run_type().execute(rustup).arg("update").status_checked()
 }
 
+pub fn run_elan(ctx: &ExecutionContext) -> Result<()> {
+    let elan = require("elan")?;
+
+    print_separator("elan");
+    ctx.run_type()
+        .execute(&elan)
+        .args(["self", "update"])
+        .status_checked()?;
+    ctx.run_type().execute(&elan).arg("update").status_checked()
+}
+
 pub fn run_juliaup(ctx: &ExecutionContext) -> Result<()> {
     let juliaup = require("juliaup")?;