Add Shell basic shell completion.

.gitignore

@@ -1,3 +1,4 @@
 /.idea
 /target
+/completions
 **/*.rs.bk

Cargo.toml

@@ -17,6 +17,9 @@ edition = "2018"
 
 autotests = false
 
+[build-dependencies]
+structopt = "0.3"
+
 [dependencies]
 toml = "0.4"
 serde = { version = '1.0.83', features = ['derive'] }

build.rs

@@ -0,0 +1,16 @@
+use std::fs;
+use structopt::clap::Shell;
+
+include!("src/cli.rs");
+
+fn main() {
+    let pkg_name = env!("CARGO_PKG_NAME");
+
+    if let Ok(outdir) = std::env::var("SHELL_COMPLETIONS_DIR") {
+
+        fs::create_dir_all(&outdir).unwrap();
+        Cli::clap().gen_completions(pkg_name, Shell::Bash, &outdir);
+        Cli::clap().gen_completions(pkg_name, Shell::Fish, &outdir);
+        Cli::clap().gen_completions(pkg_name, Shell::Zsh, &outdir);
+    }
+}

src/cli.rs

@@ -98,14 +98,13 @@ pub struct CliOpts {
 }
 
 #[derive(Debug, StructOpt)]
-#[structopt(setting = AppSettings::SubcommandsNegateReqs, author)]
+#[structopt(setting = AppSettings::SubcommandsNegateReqs, setting = AppSettings::ArgRequiredElseHelp, author)]
 /// A simple script management CLI
 pub struct Cli {
     #[structopt(flatten)]
     pub opts: CliOpts,
 
     /// The alias or name for the script.
-    #[structopt(required_unless = "cmd")]
     pub alias: Option<String>,
 
     /// Pier subcommands

src/error.rs

@@ -28,6 +28,9 @@ pub enum PierError {
         source: std::io::Error,
         path: PathBuf,
     },
+    #[snafu(display("error: AliasOrSubcommandRequired: No alias or subcommand supplied."))]
+    AliasOrSubcommandRequired,
+
     #[snafu(display("error: AliasNotFound: No script found by alias {}", alias))]
     AliasNotFound { alias: String },
 

src/lib.rs

@@ -5,7 +5,7 @@ pub mod cli;
 mod config;
 pub mod error;
 use config::Config;
-mod macros;
+pub mod macros;
 mod defaults;
 use defaults::*;
 pub mod script;

src/main.rs

@@ -1,16 +1,19 @@
+use snafu::ensure;
 use std::process;
+use structopt::clap::Shell;
 use structopt::StructOpt;
 
 use pier::{
     cli::{Cli, CliSubcommand},
-    open_editor,
+    error::*,
+    open_editor, pier_err,
     script::Script,
     Pier, Result,
 };
 
 fn main() {
     let opt = Cli::from_args();
-
+    //Cli::clap().gen_completions(env!("CARGO_PKG_NAME"), Shell::Zsh, "target");
     if let Err(err) = handle_subcommands(opt) {
         eprintln!("{}", err);
         // Only exits the process once the used memory has been cleaned up.
@@ -73,8 +76,10 @@ fn handle_subcommands(cli: Cli) -> Result<()> {
         };
     } else {
         let arg = "";
-        let alias = &cli.alias.expect("Alias is required unless subcommand.");
-        pier.run_script(alias, arg)?;
+        match &cli.alias {
+            Some(alias) => pier.run_script(&alias, arg)?,
+            None => pier_err!(PierError::AliasOrSubcommandRequired),
+        }
     }
 
     Ok(())