feat: add comment syntax for file scripts

cli/src/cli/bash.rs

@@ -0,0 +1,56 @@
+use std::fmt::Debug;
+use std::path::PathBuf;
+use std::process::Stdio;
+
+use clap::Args;
+use heck::ToSnakeCase;
+use itertools::Itertools;
+use miette::IntoDiagnostic;
+
+use usage::cli::ParseValue;
+use usage::Spec;
+
+#[derive(Debug, Args)]
+#[clap()]
+pub struct Bash {
+    script: PathBuf,
+    /// arguments to pass to script
+    #[clap(allow_hyphen_values = true)]
+    args: Vec<String>,
+}
+
+impl Bash {
+    pub fn run(&mut self) -> miette::Result<()> {
+        let (spec, _script) = Spec::parse_file(&self.script)?;
+        let mut args = self.args.clone();
+        args.insert(0, spec.bin.clone());
+        let parsed = usage::cli::parse(&spec, &args)?;
+
+        let mut cmd = std::process::Command::new("bash");
+        cmd.stdin(Stdio::inherit());
+        cmd.stdout(Stdio::inherit());
+        cmd.stderr(Stdio::inherit());
+        // TODO: set positional args
+
+        let args = vec![self.script.to_str().unwrap().to_string()]
+            .into_iter()
+            .chain(self.args.clone())
+            .collect_vec();
+        cmd.args(&args);
+
+        for (flag, val) in &parsed.flags {
+            let key = format!("usage_{}", flag.name.to_snake_case());
+            let val = match val {
+                ParseValue::Bool(b) => if *b { "1" } else { "0" }.to_string(),
+                ParseValue::String(s) => s.clone(),
+                ParseValue::MultiBool(b) => b.iter().map(|b| if *b { "1" } else { "0" }).join(","),
+                ParseValue::MultiString(_s) => unimplemented!("multi string"),
+            };
+            cmd.env(key, val);
+        }
+
+        cmd.spawn().into_diagnostic()?.wait().into_diagnostic()?;
+
+        Ok(())
+    }
+}

cli/src/cli/mod.rs

@@ -1,6 +1,7 @@
 use clap::{Parser, Subcommand};
 use miette::Result;
 
+mod bash;
 mod complete_word;
 mod exec;
 mod generate;
@@ -14,6 +15,7 @@ pub struct Cli {
 
 #[derive(Subcommand)]
 enum Command {
+    Bash(bash::Bash),
     CompleteWord(complete_word::CompleteWord),
     Exec(exec::Exec),
     Generate(generate::Generate),
@@ -23,6 +25,7 @@ impl Cli {
     pub fn run(argv: &[String]) -> Result<()> {
         let cli = Self::parse_from(argv);
         match cli.command {
+            Command::Bash(mut cmd) => cmd.run(),
             Command::Generate(cmd) => cmd.run(),
             Command::Exec(mut cmd) => cmd.run(),
             Command::CompleteWord(cmd) => cmd.run(),

docs/cli/scripts.md

@@ -1,16 +1,16 @@
 # Usage Scripts
 
 Scripts can be used with the Usage CLI to display help, powerful arg parsing, and autocompletion in any language.
-The Usage CLI can be used with "double-shebang" scripts which contain both the Usage definition and script in a
-single file. Here is an example in bash:
+Here is an example in bash:
 
 ```bash
-#!/usr/bin/env usage
-flag "-f --force" help="Overwrite existing <file>"
-flag "-u --user <user>" help="User to run as"
-arg "<file>" help="The file to write" default="file.txt"
+#!/usr/bin/env -S usage bash
+# |usage.jdx.dev|
+# flag "-f --force" help="Overwrite existing <file>"
+# flag "-u --user <user>" help="User to run as"
+# arg "<file>" help="The file to write" default="file.txt"
+# |usage.jdx.dev|
 
-#!/usr/bin/env bash
 if [ "$usage_force" = "true" ]; then
   rm -f "$usage_file"
 fi

examples/example.sh

@@ -1,11 +1,11 @@
-#!/usr/bin/env usage
+#!/usr/bin/env -S usage bash
+# |usage.jdx.dev|
+# bin "ex"
+# flag "--foo" help="Flag value"
+# flag "--bar <bar>" help="Option value"
+# arg "baz" help="Positional values"
+# |usage.jdx.dev|
 # shellcheck disable=all
-bin "ex"
-flag "--foo" help="Flag value"
-flag "--bar <bar>" help="Option value"
-arg "baz" help="Positional values"
-
-#!/usr/bin/env bash
 set -euo pipefail
 
 echo foo: $usage_foo

lib/src/parse/spec.rs

@@ -132,6 +132,9 @@ impl Spec {
 
 fn split_script(file: &Path) -> Result<(String, String), UsageErr> {
     let full = file::read_to_string(file)?;
+    if full.contains("# |usage.jdx.dev|") {
+        return Ok((extract_usage_from_comments(&full), full));
+    }
     let schema = full.strip_prefix("#!/usr/bin/env usage\n").unwrap_or(&full);
     let (schema, body) = schema.split_once("\n#!").unwrap_or((schema, ""));
     let schema = schema
@@ -144,6 +147,21 @@ fn split_script(file: &Path) -> Result<(String, String), UsageErr> {
     Ok((schema, body))
 }
 
+fn extract_usage_from_comments(full: &str) -> String {
+    let mut usage = vec![];
+    let mut inside = false;
+    for line in full.lines() {
+        if line.starts_with("# |usage.jdx.dev|") {
+            inside = !inside;
+            continue;
+        }
+        if inside {
+            usage.push(line.strip_prefix("# ").unwrap());
+        }
+    }
+    usage.join("\n")
+}
+
 fn set_subcommand_ancestors(cmd: &mut SpecCommand, ancestors: &[String]) {
     if cmd.usage.is_empty() {
         cmd.usage = cmd.usage();