refactor

3 files changed, 17 insertions, 4 deletions

diff --git a/Cargo.lock b/Cargo.lock
index fbde278..17eac54 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -466,6 +466,7 @@ dependencies = [
  "hostname",
  "libc",
  "nix",
+ "once_cell",
  "pest",
  "pest_derive",
  "pty-process",
diff --git a/Cargo.toml b/Cargo.toml
index 18b07ed..1942ac4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,6 +12,7 @@ futures-lite = "1.12.0"
 hostname = "0.3.1"
 libc = "0.2.112"
 nix = "0.23.0"
+once_cell = "1.9.0"
 pest = "2.1.3"
 pest_derive = "2.1.0"
 pty-process = { version = "0.2.0", features = ["backend-async-std"] }
diff --git a/src/state/history/builtins.rs b/src/state/history/builtins.rs
index 2b2084b..dd293a1 100644
--- a/src/state/history/builtins.rs
+++ b/src/state/history/builtins.rs
@@ -1,12 +1,23 @@
 use std::os::unix::process::ExitStatusExt as _;
 
+type Builtin = &'static (dyn Fn(&crate::parse::Exe) -> std::process::ExitStatus
+              + Sync
+              + Send);
+
+// i don't know how to do this without an as conversion
+#[allow(clippy::as_conversions)]
+static BUILTINS: once_cell::sync::Lazy<
+    std::collections::HashMap<&'static str, Builtin>,
+> = once_cell::sync::Lazy::new(|| {
+    let mut builtins = std::collections::HashMap::new();
+    builtins.insert("cd", &cd as Builtin);
+    builtins
+});
+
 pub fn run(
     exe: &crate::parse::Exe,
 ) -> Option<async_std::process::ExitStatus> {
-    match exe.exe() {
-        "cd" => Some(cd(exe)),
-        _ => None,
-    }
+    BUILTINS.get(exe.exe()).map(|f| f(exe))
 }
 
 fn cd(exe: &crate::parse::Exe) -> async_std::process::ExitStatus {