read from file or stdin, add readme

README.md

@@ -1,3 +1,39 @@
 # grassmudhorse.rs
 
 Grass Mud Horse in Rust
+
+help:
+```shell
+$ ./target/debug/grassmudhorse -h
+grassmudhorse.rs v0.1
+```
+
+execute from file:
+```shell
+$ ./target/debug/grassmudhorse print-110.gmh 
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+```
+
+execute from stdin:
+```shell
+$ cat print-110.gmh | ./target/debug/grassmudhorse
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+```

print-110.gmh

@@ -0,0 +1,16 @@
+草草草泥马
+马草草草泥草草草草泥泥马
+草马草
+泥马草泥
+草草草泥草泥草马
+泥马草草
+草草草泥马
+泥草草草
+草马草
+草草草泥草泥泥马
+泥草草泥
+马泥草草泥草草草泥草泥马
+马草马草泥草草草草泥泥马
+马草草草泥草草草泥草泥马
+草马马
+马马马

src/main.rs

@@ -4,6 +4,10 @@ mod parser;
 mod context;
 mod vm;
 
+use std::{
+    env,
+    fs::read_to_string,
+};
 use err::*;
 use parser::*;
 use context::*;
@@ -13,16 +17,45 @@ use vm::*;
 // https://playsecurity.org/rawfile/grass_mud_horse_language_specification.md
 // https://p.rogram.me/grassmudhorse.js/grassmudhorse.js
 fn main() {
-    let input = "草草草泥马 马草草草泥草草草草泥泥马 草马草 泥马草泥 草草草泥草泥草马 泥马草草 草草草泥马 泥草草草 草马草 草草草泥草泥泥马 泥草草泥 马泥草草泥草草草泥草泥马 马草马草泥草草草草泥泥马 马草草草泥草草草泥草泥马 草马马 马马马";
+    let is_help = env::args().any(|a| a == "-h" || a == "--help");
+    if is_help {
+        println!("grassmudhorse.rs v0.1");
+        return;
+    }
+    let is_debug = env::args().any(|a| a == "-d" || a == "--debug");
 
-    let instructions = match parse_lang(input) {
+    let arg_file = env::args().filter(|a| !a.starts_with("-")).nth(1);
+
+    let input = match arg_file {
+        Some(f) => match read_to_string(&f) {
+            Ok(s) => s, Err(err) => {
+                println!("[ERROR] Read file {}, error: {}", f, err);
+                return;
+            }
+        },
+        None => {
+            let mut buff = String::new();
+            use std::io::Read;
+            match std::io::stdin().lock().read_to_string(&mut buff) {
+                Ok(_) => buff,
+                Err(err) => {
+                    println!("[ERROR] Read stdin, error: {}", err);
+                    return;
+                }
+            }
+        },
+    };
+    
+    
+
+    let instructions = match parse_lang(&input) {
         Ok(i) => i, Err(err) => {
             println!("Parse error: {}", err);
             return;
         },
     };
 
-    let mut context = Context::new(false);
+    let mut context = Context::new(is_debug);
 
     if context.is_debug() {
         println!("[DEBUG] parsed instructions:");