diff --git a/src/err.rs b/src/err.rs
new file mode 100644
index 0000000..687d503
--- /dev/null
+++ b/src/err.rs
@@ -0,0 +1,7 @@
+use err_derive::Error;
+
+#[derive(Debug, Error)]
+pub enum ParseError {
+    #[error(display = "error syntax: {:?}", _0)]
+    ErrorSyntax(String),
+}
diff --git a/src/ins.rs b/src/ins.rs
new file mode 100644
index 0000000..10a9d49
--- /dev/null
+++ b/src/ins.rs
@@ -0,0 +1,104 @@
+
+#[derive(Debug)]
+pub enum InsType {
+    Path(InsColl),
+    Node(Instruction),
+}
+
+#[derive(Debug)]
+pub struct Ins {
+    pub c: char,
+    pub ins_type: InsType,
+}
+
+#[derive(Debug)]
+pub struct InsColl {
+    pub inses: Vec<Ins>,
+}
+
+pub fn make_instruction_tree() -> InsColl {
+    InsColl{ inses: vec![
+        Ins{ c: '草', ins_type: InsType::Path(InsColl{ inses: vec![
+            Ins{ c: '草', ins_type: InsType::Node(Instruction::Push) },
+            Ins{ c: '马', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '草', ins_type: InsType::Node(Instruction::Dup) },
+                Ins{ c: '泥', ins_type: InsType::Node(Instruction::Swap) },
+                Ins{ c: '马', ins_type: InsType::Node(Instruction::Pop) }
+            ]})},
+            Ins{ c: '泥', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '草', ins_type: InsType::Node(Instruction::CopyN) },
+                Ins{ c: '马', ins_type: InsType::Node(Instruction::PopN) }
+            ]})},
+        ]})},
+        Ins{ c: '泥', ins_type: InsType::Path(InsColl{ inses: vec![
+            Ins{ c: '草', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '草', ins_type: InsType::Path(InsColl{ inses: vec![
+                    Ins{ c: '草', ins_type: InsType::Node(Instruction::Add) },
+                    Ins{ c: '泥', ins_type: InsType::Node(Instruction::Sub) },
+                    Ins{ c: '马', ins_type: InsType::Node(Instruction::Mul) },
+                ]})},
+                Ins{ c: '泥', ins_type: InsType::Path(InsColl{ inses: vec![
+                    Ins{ c: '草', ins_type: InsType::Node(Instruction::Div) },
+                    Ins{ c: '泥', ins_type: InsType::Node(Instruction::Mod) },
+                ]})},
+            ]})},
+            Ins{ c: '泥', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '草', ins_type: InsType::Node(Instruction::Store) },
+                Ins{ c: '泥', ins_type: InsType::Node(Instruction::Retrieve) },
+            ]})},
+            Ins{ c: '马', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '草', ins_type: InsType::Path(InsColl{ inses: vec![
+                    Ins{ c: '草', ins_type: InsType::Node(Instruction::StdOutChar) },
+                    Ins{ c: '泥', ins_type: InsType::Node(Instruction::StdOutNum) },
+                ]})},
+                Ins{ c: '泥', ins_type: InsType::Path(InsColl{ inses: vec![
+                    Ins{ c: '草', ins_type: InsType::Node(Instruction::StdInChar) },
+                    Ins{ c: '泥', ins_type: InsType::Node(Instruction::StdInNum) },
+                ]})},
+            ]})},
+        ]})},
+        Ins{ c: '马', ins_type: InsType::Path(InsColl{ inses: vec![
+            Ins{ c: '草', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '草', ins_type: InsType::Node(Instruction::DefineLabel) },
+                Ins{ c: '泥', ins_type: InsType::Node(Instruction::CallAtLabel) },
+                Ins{ c: '马', ins_type: InsType::Node(Instruction::GotoLabel) },
+            ]})},
+            Ins{ c: '泥', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '草', ins_type: InsType::Node(Instruction::GotoLabelE0) },
+                Ins{ c: '泥', ins_type: InsType::Node(Instruction::GotoLabelL0) },
+                Ins{ c: '马', ins_type: InsType::Node(Instruction::ReturnCallAt) },
+            ]})},
+            Ins{ c: '马', ins_type: InsType::Path(InsColl{ inses: vec![
+                Ins{ c: '马', ins_type: InsType::Node(Instruction::End) },
+            ]})},
+        ]})},
+    ]}
+}
+
+#[derive(Debug, Clone)]
+pub enum Instruction {
+    Push,
+    Dup,
+    CopyN,
+    Swap,
+    Pop,
+    PopN,
+    Add,
+    Sub,
+    Mul,
+    Div,
+    Mod,
+    Store,
+    Retrieve,
+    DefineLabel,
+    CallAtLabel,
+    GotoLabel,
+    GotoLabelE0,
+    GotoLabelL0,
+    ReturnCallAt,
+    End,
+    StdOutChar,
+    StdOutNum,
+    StdInChar,
+    StdInNum,
+}
diff --git a/src/main.rs b/src/main.rs
index e3e450d..7544fdd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,112 +1,82 @@
-use err_derive::Error;
+pub mod err;// TODO ...
+mod ins;
 
-#[derive(Debug, Error)]
-pub enum ParseError {
-    #[error(display = "error syntax: {:?}", _0)]
-    ErrorSyntax(String),
-}
-
-#[derive(Debug)]
-enum Instruction {
-    Push,
-    Dup,
-    CopyN,
-    Swap,
-    Pop,
-    PopN,
-    Add,
-    Sub,
-    Mul,
-    Div,
-    Mod,
-    Store,
-    Retrieve,
-    DefineLabel,
-    CallAtLabel,
-    GotoLabel,
-    GotoLabelE0,
-    GotoLabelL0,
-    ReturnCallAt,
-    End,
-    StdOutChar,
-    StdOutNum,
-    StdInChar,
-    StdInNum,
-}
-
-struct ParseChars {
-    index: usize,
-    chars: Vec<char>,
-}
-
-impl ParseChars {
-    fn next(&mut self) -> Option<char> {
-        let c = self.try_next();
-        if c.is_some() { self.index += 1; }
-        c
-    }
-
-    fn try_next(&self) -> Option<char> {
-        self.try_next_n(0_usize)
-    }
-
-    fn try_next_n(&self, nn: usize) -> Option<char> {
-        let i = self.index + nn;
-        if i >= self.chars.len() {
-            None
-        } else {
-            let c = self.chars[i];
-            Some(c)
-        }
-    }
-}
+use ins::*;
 
 const VALID_INSTRUCTION_CHARS: &str = "草泥马河蟹";
 
+// 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 mut cs = "草草草泥草泥泥马".chars();
+    println!("{}", read_number(&mut cs));
     println!("{:?}", parse_lang(input));
 }
 
-fn parse_lang(lang: &str) -> Result<Vec<Instruction>, ParseError> {
-    let mut r = vec![];
-
-    let mut cs = ParseChars{ index: 0_usize, chars: lang.chars().filter(|c| {
-        VALID_INSTRUCTION_CHARS.chars().any(|vic| vic == *c)
-    }).collect(), };
-    while let Some(c) = cs.next() {
-        let nc = match cs.try_next() {
-            Some(nc) => nc, None => {
-                return Err(ParseError::ErrorSyntax(
-                    format!("Syntax error: after {} has no valid char", c)
-                ));
-            },
-        };
-        if c == '草' && nc == '草' { // Push
-            cs.next();
-            // todo parse
-            continue;
+fn read_number(cs: &mut dyn Iterator<Item=char>) -> isize {
+    let mut is_positive = 1_isize;
+    if let Some(c) = cs.next() {
+        if c == '草' {
+            is_positive = 1;
+        } else if c == '泥' {
+            is_positive = -1;
+        } else {
+            // Syntax ERROR!
         }
-        let nnc = match cs.try_next_n(1) {
-            Some(nc) => nc, None => {
-                return Err(ParseError::ErrorSyntax(
-                    format!("Syntax error: after {}{} has no valid char", c, nc)
-                ));
-            },
-        };
-        if c == '草' && nc == '马' || nnc == '草' { // Dup
-
-        }
-        let nnnc = match cs.try_next_n(2) {
-            Some(nc) => nc, None => {
-                return Err(ParseError::ErrorSyntax(
-                    format!("Syntax error: after {}{}{} has no valid char", c, nc, nnc)
-                ));
-            },
-        };
+    } else {
+        // Syntax ERROR!
     }
-
-    Ok(r)
+    let mut num = 0_isize;
+    while let Some(c) = cs.next() {
+        if c == '马' {
+            break;
+        } else {
+            num <<= 1;
+            num += if c == '草' { 0 } else { 1 };
+        }
+    }
+    is_positive * num
 }
 
+fn match_instruction(ins_coll: &InsColl, cs: &mut dyn Iterator<Item=char>) -> Option<Instruction> {
+    if let Some(c) = cs.next() {
+        for ins in &ins_coll.inses {
+            if ins.c == c {
+                match &ins.ins_type {
+                    InsType::Path(ins_coll) => return match_instruction(&ins_coll, cs),
+                    InsType::Node(ins) => {
+                        println!("{:?}", ins);
+                        return Some(ins.clone());
+                    },
+                }
+            }
+        }
+        println!("ERROR!!!! syntax error!");
+    }
+    None
+}
+
+fn parse_lang(lang: &str) {// -> Result<Vec<Instruction>, ParseError> {
+    // let mut r = vec![];
+
+    let instruction_tree_root = make_instruction_tree();
+
+    let mut cs = lang.chars().filter(|c| {
+        VALID_INSTRUCTION_CHARS.chars().any(|vic| vic == *c)
+    });
+
+    while let Some(ins) = match_instruction(&instruction_tree_root, &mut cs) {
+        println!("{:?}", ins);
+    }
+}
+
+#[test]
+fn test_read_number() {
+    assert_eq!(read_number(&mut "草泥马".chars()), 1);
+    assert_eq!(read_number(&mut "草泥草草草草泥泥马".chars()), 67);
+    assert_eq!(read_number(&mut "草泥草泥泥马".chars()), 11);
+    assert_eq!(read_number(&mut "草泥草草草泥草泥马".chars()), 69);
+}