1 files changed, 31 insertions, 0 deletions
diff --git a/src/bin/subplot.rs b/src/bin/subplot.rs
index 94c4b53..fabb0f2 100644
--- a/src/bin/subplot.rs
+++ b/src/bin/subplot.rs
@@ -6,6 +6,7 @@ use anyhow::Result;
 use structopt::StructOpt;
 use subplot::{resource, DataFile, Document, Style};
 
+use std::convert::TryFrom;
 use std::fs::{write, File};
 use std::io::{Read, Write};
 use std::path::{Path, PathBuf};
@@ -32,6 +33,7 @@ impl Toplevel {
 enum Cmd {
     Extract(Extract),
     Filter(Filter),
+    Metadata(Metadata),
 }
 
 impl Cmd {
@@ -39,6 +41,7 @@ impl Cmd {
         match self {
             Cmd::Extract(e) => e.run(),
             Cmd::Filter(f) => f.run(),
+            Cmd::Metadata(m) => m.run(),
         }
     }
 }
@@ -150,6 +153,34 @@ impl Filter {
     }
 }
 
+#[derive(Debug, StructOpt)]
+/// Extract metadata about a document
+///
+/// Load and process a subplot document, extracting various metadata about the
+/// document.  This can then render that either as a plain text report for humans,
+/// or as a JSON object for further scripted processing.
+struct Metadata {
+    /// Form that you want the output to take
+    #[structopt(short = "o", default_value = "plain", possible_values=&["plain", "json"])]
+    output_format: cli::OutputFormat,
+
+    /// Input subplot document filename
+    #[structopt(parse(from_os_str))]
+    filename: PathBuf,
+}
+
+impl Metadata {
+    fn run(&self) -> Result<()> {
+        let mut doc = cli::load_document(&self.filename, Style::default())?;
+        let meta = cli::Metadata::try_from(&mut doc)?;
+        match self.output_format {
+            cli::OutputFormat::Plain => meta.write_out(),
+            cli::OutputFormat::Json => println!("{}", serde_json::to_string_pretty(&meta)?),
+        }
+        Ok(())
+    }
+}
+
 fn main() {
     let args = Toplevel::from_args();
     args.resources.handle();