Add structopt and base argument parsing

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/main.rs

@@ -1,6 +1,68 @@
 mod syn;
-//mod util;
 
-fn main() {
-    println!("Hello, world!");
+use std::{
+    convert::TryFrom,
+    fs,
+    io::{stdout, Write},
+    path::{Path, PathBuf},
+    process,
+};
+use structopt::StructOpt;
+
+type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
+
+#[derive(StructOpt, Debug)]
+struct Options {
+    /// The input file to work with.
+    ///
+    /// By default, the file will be executed. If -c is passed, it will not run and only compile.
+    /// Supplying - for the path will read from STDIN.
+    #[structopt(name = "FILE", parse(from_os_str))]
+    input: PathBuf,
+
+    /*
+    /// Disassemble object that would be passed to VM and exit before running it.
+    #[structopt(short = "d", long)]
+    disassemble: bool,
+    */
+}
+
+fn main() -> Result<()> {
+    use syn::{
+        parser::Parser,
+    };
+
+    let opt = Options::from_args();
+    let text = fs::read_to_string(&opt.input)?;
+    let parser = Parser::try_from(text.as_str())?;
+    /*
+    let object = assemble::assemble_path(&opt.input)?;
+
+    if opt.compile_only {
+        let outfile = opt.out.clone().unwrap_or_else(|| {
+            let mut outfile = opt.input.clone();
+            assert!(outfile.set_extension("obj"));
+            outfile
+        });
+        let bytes = object.to_bytes();
+        let mut writer = get_writer(&outfile)?;
+        writer.write(&bytes)?;
+        Ok(())
+    } else if opt.disassemble {
+        let outfile = opt
+            .out
+            .as_ref()
+            .map(|p| p.as_path())
+            .unwrap_or_else(|| Path::new("-"));
+        let mut writer = get_writer(&outfile)?;
+        object.disasm(&mut writer)?;
+        Ok(())
+    } else {
+        let mut state = State::new();
+        state.load_object(object, opt.max_mem.unwrap_or(DEFAULT_MAX_MEM))?;
+        let status = state.exec()?;
+        process::exit((status & 0xffff_ffff) as i32);
+    }
+    */
+    Ok(())
 }