feat: add version / build information

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [0.5.0] - UNRELEASED
 
 Feat [#5](https://github.com/coriolinus/calc/issues/5): choose backing value type at evaluation time, not CLI
+Feat [#25](https://github.com/coriolinus/calc/issues/25): add version/build info and `-V`/`--version` flags
 
 ## [0.4.0] - 2022-08-07
 

Cargo.toml

@@ -12,6 +12,7 @@ categories = [
     "mathematics",
 ]
 keywords = ["calculator", "cli"]
+build = "build.rs"
 
 [dependencies]
 anyhow = { version = "1.0.94", optional = true }
@@ -28,6 +29,7 @@ thiserror = "1.0.69"
 
 [build-dependencies]
 lalrpop = "0.20.2"
+vergen-gitcl = { version = "1.0.8", features = ["build"] }
 
 [features]
 default = ["cli"]

build.rs

@@ -1,3 +1,22 @@
-fn main() {
+use vergen_gitcl::{BuildBuilder, Emitter, GitclBuilder};
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // regenerate lalrpop parser
     lalrpop::process_root().unwrap();
+
+    // gather build info
+    let build = BuildBuilder::default().build_timestamp(true).build()?;
+    let git = GitclBuilder::default()
+        .branch(true)
+        .sha(false)
+        .dirty(false)
+        .build()?;
+
+    // emit build data into the build environment
+    Emitter::new()
+        .add_instructions(&build)?
+        .add_instructions(&git)?
+        .emit()?;
+
+    Ok(())
 }