From 42826cc78fbbbaf04a162f23863a96268bf0bfe0 Mon Sep 17 00:00:00 2001
From: Hatter Jiang <jht5945@gmail.com>
Date: Wed, 6 May 2020 00:23:55 +0800
Subject: [PATCH] ref read_number

---
 src/main.rs | 43 ++++++++++++++++++++-----------------------
 1 file changed, 20 insertions(+), 23 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 18c62be..745c4bc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -40,7 +40,7 @@ fn match_instruction(ins_coll: &InsColl, cs: &mut dyn Iterator<Item=char>) -> Re
                 match &ins.ins_type {
                     InsType::Path(ins_coll) => return match_instruction(&ins_coll, cs),
                     InsType::Node(ins) => {
-                        let data = if ins.has_data() { Some(read_number(cs)) } else { None };
+                        let data = if ins.has_data() { Some(read_number(cs)?) } else { None };
                         println!("{:?} {}", ins, if let Some(n) = data { n.to_string() } else { "".to_owned() }); // TODO
                         return Ok(Some(ins.new_instruction(data)));
                     },
@@ -53,35 +53,32 @@ fn match_instruction(ins_coll: &InsColl, cs: &mut dyn Iterator<Item=char>) -> Re
     Ok(None)
 }
 
-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!
+fn read_number(cs: &mut dyn Iterator<Item=char>) -> Result<isize, ParseError> {
+    let is_positive = if let Some(c) = cs.next() {
+        if c == '草' { 1 } else if c == '泥' { -1 } else {
+            return Err(ParseError::ErrorSyntax("ERROR!!!! syntax error!".into()));
         }
     } else {
-        // Syntax ERROR!
-    }
+        return Err(ParseError::ErrorSyntax("ERROR!!!! syntax error!".into()));
+    };
     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 };
+    loop {
+        if let Some(c) = cs.next() {
+            if c == '马' {
+                break;
+            } else {
+                num <<= 1;
+                num += if c == '草' { 0 } else { 1 };
+            }
         }
     }
-    is_positive * num
+    Ok(is_positive * num)
 }
 
 #[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);
+    assert_eq!(read_number(&mut "草泥马".chars()).unwrap(), 1);
+    assert_eq!(read_number(&mut "草泥草草草草泥泥马".chars()).unwrap(), 67);
+    assert_eq!(read_number(&mut "草泥草泥泥马".chars()).unwrap(), 11);
+    assert_eq!(read_number(&mut "草泥草草草泥草泥马".chars()).unwrap(), 69);
 }