Option parsing and version

Add some basic logic for parsing commandline arguments. Also, use
build.rs to embed the program version (and git commit) during the
compile step. The program currently accepts the '--version' commandline
argument to print the version, then quit.

2 files changed, 33 insertions, 0 deletions

diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..fef4321
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,16 @@
+use std::process::Command;
+
+fn main() {
+    let build = String::from_utf8_lossy(
+        &Command::new("git")
+            .args(&["rev-parse", "HEAD"])
+            .output()
+            .unwrap()
+            .stdout,
+    )
+    .to_string();
+    println!(
+        "cargo::rustc-env=DWVSH_BUILD={}",
+        build.get(0..10).unwrap_or(&build)
+    );
+}
diff --git a/src/main.rs b/src/main.rs
index 821dde2..f87b69d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -82,6 +82,20 @@ fn repl(away: &mut Arc<Mutex<bool>>, env: &mut Environment) {
     }
 }
 
+fn options() {
+    let args: Vec<String> = env::args().collect();
+    for arg in args.iter() {
+        if arg.eq("--version") {
+            println!(
+                "dwvsh v{} ({})",
+                env!("CARGO_PKG_VERSION"),
+                env!("DWVSH_BUILD")
+            );
+            std::process::exit(0);
+        }
+    }
+}
+
 /// Shell entry
 ///
 /// Shell setup and entry
@@ -108,6 +122,9 @@ fn main() {
         .unwrap();
     };
 
+    // Parse flags and other arguments
+    options();
+
     // Begin evaluating commands
     repl(&mut away, &mut env);
 }