feat: Add JSON output to flycomp

flycomp/.cargo/config.toml

@@ -0,0 +1,5 @@
+[target.x86_64-unknown-linux-musl]
+rustflags = ["-C", "target-feature=+crt-static"]
+
+[target.aarch64-unknown-linux-musl]
+rustflags = ["-C", "target-feature=+crt-static"]

flycomp/Cargo.toml

@@ -16,3 +16,5 @@ anyhow = "1.0.102"
 clap = { version = "4.6.1", features = ["derive"] }
 clap_complete = { version = "4.6.3", features = ["unstable-dynamic"] }
 log = "0.4"
+serde = { version = "1.0.228", features = ["derive"] }
+serde_json = "1.0.149"

flycomp/src/lib.rs

@@ -11,7 +11,7 @@
 // ──────────────────────────────────────────────────────────────────────────────
 
 /// A single command-line argument / flag.
-#[derive(Debug, Clone, Default, PartialEq)]
+#[derive(Debug, Clone, Default, PartialEq, serde::Serialize)]
 pub struct Arg {
     /// Long flag name, e.g. `--verbose`.
     pub long: Option<String>,
@@ -26,7 +26,7 @@ pub struct Arg {
 }
 
 /// A parsed command (or sub-command).
-#[derive(Debug, Clone, Default, PartialEq)]
+#[derive(Debug, Clone, Default, PartialEq, serde::Serialize)]
 pub struct Command {
     /// Name of the command, if known.
     pub name: Option<String>,
@@ -842,7 +842,7 @@ fn find_subcommand_mut<'a>(root: &'a mut Command, path: &[String]) -> Option<&'a
 ///
 /// Many tools print their help to *stderr* rather than *stdout*; this function
 /// returns whichever stream is non-empty (preferring stdout).
-pub(crate) fn run_help(command_path: &str, extra_args: &[&str]) -> anyhow::Result<String> {
+pub fn run_help(command_path: &str, extra_args: &[&str]) -> anyhow::Result<String> {
     let output = std::process::Command::new(command_path)
         .args(extra_args)
         .arg("--help")

flycomp/src/main.rs

@@ -1,19 +1,48 @@
 use clap::Parser;
 
+#[derive(Clone, Debug, clap::ValueEnum)]
+#[value(rename_all = "lower")]
+enum OutputFormat {
+    Bash,
+    Elvish,
+    Fish,
+    Powershell,
+    Zsh,
+    Json,
+}
+
 #[derive(Parser, Debug)]
 #[command(name = "flycomp")]
 #[command(about = "Generate shell completions from COMMAND --help output")]
 struct CliArgs {
     /// Command name or path to synthesize completions for.
     command: String,
-    /// Output shell type (defaults to bash).
-    #[arg(long, value_enum, default_value_t = clap_complete::Shell::Bash)]
-    shell: clap_complete::Shell,
+    /// Output format (defaults to bash).
+    #[arg(long, value_enum, default_value_t = OutputFormat::Bash)]
+    output: OutputFormat,
 }
 
 fn main() -> anyhow::Result<()> {
     let args = CliArgs::parse();
-    let script = flycomp::generate_completion_script(&args.command, args.shell)?;
-    print!("{}", script);
+
+    if matches!(args.output, OutputFormat::Json) {
+        let parsed_cmd = flycomp::synthesize_completion(&args.command, |extra_args| {
+            flycomp::run_help(&args.command, extra_args)
+        })?;
+        let json = serde_json::to_string_pretty(&parsed_cmd)?;
+        println!("{}", json);
+    } else {
+        let shell = match args.output {
+            OutputFormat::Bash => clap_complete::Shell::Bash,
+            OutputFormat::Elvish => clap_complete::Shell::Elvish,
+            OutputFormat::Fish => clap_complete::Shell::Fish,
+            OutputFormat::Powershell => clap_complete::Shell::PowerShell,
+            OutputFormat::Zsh => clap_complete::Shell::Zsh,
+            OutputFormat::Json => unreachable!(),
+        };
+        let script = flycomp::generate_completion_script(&args.command, shell)?;
+        print!("{}", script);
+    }
+
     Ok(())
 }