Merge remote changes

cli/.gitignore

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+/target

cli/Cargo.toml

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+[package]
+name = "hyperbuild-cli"
+publish = false
+version = "0.1.1"
+authors = ["Wilson Lin <code@wilsonl.in>"]
+edition = "2018"
+
+[dependencies]
+hyperbuild = { path = ".." }
+structopt = "0.3.5"

cli/src/main.rs

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+use std::fs::File;
+use std::io::{Read, stdin, stdout, Write};
+
+use structopt::StructOpt;
+
+use hyperbuild::{FriendlyError, hyperbuild_friendly_error};
+
+#[derive(StructOpt)]
+struct Cli {
+    #[structopt(short, long, parse(from_os_str))]
+    src: Option<std::path::PathBuf>,
+    #[structopt(short, long, parse(from_os_str))]
+    out: Option<std::path::PathBuf>,
+}
+
+macro_rules! io_expect {
+    ($expr:expr, $msg:literal) => {
+        match $expr {
+            Ok(r) => r,
+            Err(e) => {
+                eprintln!("Error: {}", $msg);
+                eprintln!("{}", e);
+                return;
+            }
+        }
+    };
+}
+
+fn main() {
+    let args = Cli::from_args();
+    let mut code = Vec::<u8>::new();
+    let mut src_file: Box<dyn Read> = match args.src {
+        Some(p) => Box::new(io_expect!(File::open(p), "could not open source file")),
+        None => Box::new(stdin()),
+    };
+    io_expect!(src_file.read_to_end(&mut code), "could not load source code");
+    match hyperbuild_friendly_error(&mut code) {
+        Ok(out_len) => {
+            let mut out_file: Box<dyn Write> = match args.out {
+                Some(p) => Box::new(io_expect!(File::create(p), "could not open output file")),
+                None => Box::new(stdout()),
+            };
+            io_expect!(out_file.write_all(&code[..out_len]), "could not save minified code");
+        }
+        Err(FriendlyError { position, message, code_context }) => {
+            eprintln!("Failed at character {}:", position);
+            eprintln!("{}", message);
+            if args.out.is_some() {
+                eprintln!("The output file has not been touched.");
+            };
+            eprintln!("--------");
+            eprintln!("{}", code_context);
+        }
+    };
+}