Changeset 901

Timestamp:

03/09/10 20:21:18 (5 months ago)

Author:

zoogie

Message:

Split Execute() into separate Compile() and CallAndPrint() steps for finer-grained control.

Location:

trunk/engine/Script

Files:

• Core.cpp (modified) (2 diffs)
• Core.h (modified) (1 diff)

trunk/engine/Script/Core.cpp

@@ -168 +168 @@
 
 /**
- * Execute a chunk of code.
- * @param chunk The code to execute.
+ * Compile a chunk of code.
+ * Upon successful execution, the compiled chunk will be pushed to the stack.
+ * @param chunk The code to compile.
  * @throw IncompleteExn If the code does not complete a statement; i.e.,
  *                      expecting more tokens.  Callers can catch this
  *                      to keep reading more data to finish the statement.
- * @throw ScriptExn The code either failed to compile or signaled an error
- *                  while executing.
- */
-void Core::Execute(const std::string &chunk)
-{
-    // Compile the chunk.
+ * @throw ScriptExn The code failed to compile.
+ */
+void Core::Compile(const std::string &chunk)
+{
     int status = luaL_loadbuffer(state, chunk.c_str(), chunk.length(), "=lua");
     if (status != 0) {
@@ -192 +191 @@
         }
     }
+}
+
+/**
+ * Pop a function off the stack and execute it, printing any return values.
+ * @throw ScriptExn The code signaled an error while executing.
+ */
+void Core::CallAndPrint()
+{
+    int initStack = lua_gettop(state);
+    if (initStack == 0) {
+        throw ScriptExn("No function on stack.");
+    }
+    --initStack;
 
     // Execute the chunk.
-    status = lua_pcall(state, 0, LUA_MULTRET, 0);
+    int status = lua_pcall(state, 0, LUA_MULTRET, 0);
     if (status != 0) {
         throw ScriptExn(PopError());
     }
 
+    int numReturns = lua_gettop(state) - initStack;
+
     // If there were any return values, pass them to print().
-    if (lua_gettop(state) > 0) {
+    if (numReturns > 0) {
         lua_getglobal(state, "print");
-        lua_insert(state, 1);
-        status = lua_pcall(state, lua_gettop(state) - 1, 0, 0);
+        lua_insert(state, initStack + 1);
+        status = lua_pcall(state, numReturns, 0, 0);
         if (status != 0) {
             throw ScriptExn(PopError());
         }
     }
-
-    // Ensure that the stack is now empty for the next run.
-    lua_settop(state, 0);
+}
+
+/**
+ * Compile and execute a chunk of code.
+ * @param chunk The code to execute.
+ * @throw IncompleteExn If the code does not complete a statement; i.e.,
+ *                      expecting more tokens.  Callers can catch this
+ *                      to keep reading more data to finish the statement.
+ * @throw ScriptExn The code either failed to compile or signaled an error
+ *                  while executing.
+ */
+void Core::Execute(const std::string &chunk)
+{
+    Compile(chunk);
+    CallAndPrint();
 }
 

trunk/engine/Script/Core.h

@@ -75 +75 @@
 
     public:
+        void Compile(const std::string &chunk);
+        void CallAndPrint();
+
         void Execute(const std::string &chunk);