From 4f3e7d31b979a0cf10dad609832392bd9469d2ea Mon Sep 17 00:00:00 2001
From: aozhiwei <aozhiwei@kingsome.cn>
Date: Fri, 3 Mar 2023 18:02:22 +0800
Subject: [PATCH] 1

---
 a8/lisp.cc | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 a8/lisp.h  |  3 ++-
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/a8/lisp.cc b/a8/lisp.cc
index 5059a23..f879e1e 100644
--- a/a8/lisp.cc
+++ b/a8/lisp.cc
@@ -1,5 +1,7 @@
 #include <a8/a8.h>
 
+#include <ctype.h>
+
 #include <a8/lisp.h>
 
 namespace a8
@@ -95,9 +97,52 @@ namespace a8
                  });
         }
 
-        std::shared_ptr<Value> Expr::Compile(const std::string& script, std::shared_ptr<Scope> scope)
+        std::shared_ptr<Value> Expr::Compile(const std::string& script, std::shared_ptr<Scope> env)
         {
+            int pos = 0;
+            while (true) {
+                std::string token;
+                int n = GetToken(script, pos, token);
+                if (n != 1) {
+                    break;
+                }
+            }
+        }
 
+        /*
+          1: token
+          -1: end
+         */
+        int Expr::GetToken(const std::string& script, int& pos, std::string& token)
+        {
+            if (pos >= script.size()) {
+                return -1;
+            }
+            while (pos < script.size() && isspace(script[pos])) {
+                ++pos;
+            }
+            if (pos >= script.size()) {
+                return -1;
+            }
+            if (script[pos] == '(') {
+                ++pos;
+                token = "(";
+                return 1;
+            }
+            if (script[pos] == ')') {
+                ++pos;
+                token = ")";
+                return 1;
+            }
+            while (pos < script.size() && !isspace(script[pos])) {
+                token += script[pos];
+                ++pos;
+            }
+            if (token.empty()) {
+                return -1;
+            } else {
+                return 1;
+            }
         }
 
         std::shared_ptr<Value> Expr::Eval(std::shared_ptr<Value> x, std::shared_ptr<Scope> env)
diff --git a/a8/lisp.h b/a8/lisp.h
index c462e7e..bb2b7bf 100644
--- a/a8/lisp.h
+++ b/a8/lisp.h
@@ -66,10 +66,11 @@ namespace a8
         {
         public:
 
-            static std::shared_ptr<Value> Compile(const std::string& script, std::shared_ptr<Scope> scope);
+            static std::shared_ptr<Value> Compile(const std::string& script, std::shared_ptr<Scope> env);
             static std::shared_ptr<Value> Eval(std::shared_ptr<Value> x, std::shared_ptr<Scope> env);
 
         private:
+            static int GetToken(const std::string& script, int& pos, std::string& token);
         };
 
     }