From 55ff07fdddffb794bb86b18dfd403f78ead6f0ec Mon Sep 17 00:00:00 2001
From: Robert Vollmert <rvollmert@gmx.net>
Date: Wed, 28 Oct 2009 12:40:18 +0100
Subject: A lot more functional, now, though still deficient.

---
 crawl-ref/source/luaterp.cc | 119 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 107 insertions(+), 12 deletions(-)

(limited to 'crawl-ref/source/luaterp.cc')

diff --git a/crawl-ref/source/luaterp.cc b/crawl-ref/source/luaterp.cc
index a2c4ec8b42..39252d1fa3 100644
--- a/crawl-ref/source/luaterp.cc
+++ b/crawl-ref/source/luaterp.cc
@@ -1,3 +1,10 @@
+/*
+ * File:     luaterp.cc
+ * Summary:  An interactive lua interpreter.
+ *
+ * Based heavily on lua.c from the Lua distribution.
+ */
+
 #include "AppHdr.h"
 
 #include "luaterp.h"
@@ -6,28 +13,116 @@
 #include "clua.h"
 #include "dlua.h"
 
-void _debug_call_lua(lua_State *ls)
+static int _incomplete(lua_State *ls, int status)
 {
-    char specs[80];
-    while (true)
+    if (status == LUA_ERRSYNTAX)
+    {
+        size_t lmsg;
+        const char *msg = lua_tolstring(ls, -1, &lmsg);
+        const char *tp = msg + lmsg - (sizeof(LUA_QL("<eof>")) - 1);
+        if (strstr(msg, LUA_QL("<eof>")) == tp)
+        {
+            lua_pop(ls, 1);
+            return 1;
+        }
+    }
+    return 0;
+}
+
+static int _pushline(lua_State *ls, int firstline)
+{
+    char buffer[80];
+    char *b = buffer;
+    size_t l;
+    mpr(firstline ? "> " : ". ", MSGCH_PROMPT);
+    get_input_line(buffer, sizeof(buffer));  
+    l = strlen(b);
+    if (l == 0)
+        return (0);
+
+    if (l > 0 && b[l-1] == '\n')   // line ends with newline?
+        b[l-1] = '\0';             // remove it
+    if (firstline && b[0] == '=')  // first line starts with `=' ?
+        lua_pushfstring(ls, "return %s", b+1);  // change it to `return'
+    else
+        lua_pushstring(ls, b);
+    return 1;
+}
+
+static int _loadline(lua_State *ls)
+{
+    int status;
+    lua_settop(ls, 0);
+
+    if (!_pushline(ls, 1))
+        return -1;  /* no input */
+
+    // repeat until gets a complete line
+    for (;;)
     {
-        mpr("> ", MSGCH_PROMPT);
-        get_input_line(specs, sizeof(specs));
-        std::string s = specs;
+        status = luaL_loadbuffer(ls, lua_tostring(ls, 1),
+                                     lua_strlen(ls, 1), "=terp");
 
-        if (s.empty())
-            return;
+        if (!_incomplete(ls, status)) 
+            break;
+        if (!_pushline(ls, 0))
+            return -1;
+        lua_pushliteral(ls, "\n");  // add a new line...
+        lua_insert(ls, -2);         // ...between the two lines
+        lua_concat(ls, 3);          // join them
+    }
+    lua_remove(ls, 1);              // remove line
+    return status;
+}
 
-        int err = 0;
-        if (err = luaL_dostring(ls, s.c_str()))
+static int _docall(lua_State *ls)
+{
+    int status;
+    int base = lua_gettop(ls);
+    status = lua_pcall(ls, 0, LUA_MULTRET, base);
+    if (status != 0)
+        lua_gc(ls, LUA_GCCOLLECT, 0);
+    return (status);
+}
+
+static int _report(lua_State *ls, int status)
+{
+    if (status && !lua_isnil(ls, -1))
+    {
+        const char *msg = lua_tostring(ls, -1);
+        if (msg == NULL)
+            msg = "(error object is not a string)";
+        mprf(MSGCH_ERROR, msg);
+        lua_pop(ls, 1);
+    }
+    return status;
+}
+
+void run_clua_interpreter(lua_State *ls)
+{
+    int status;
+    while ((status = _loadline(ls)) != -1)
+    {
+        if (status == 0)
+            status = _docall(ls);
+        _report(ls, status);
+        if (status == 0 && lua_gettop(ls) > 0)
         {
-            mprf(MSGCH_ERROR, "lua error: %d", err);
+            lua_getglobal(ls, "__echo");
+            lua_insert(ls, 1);
+            if (lua_pcall(ls, lua_gettop(ls) - 1, 0, 0) != 0)
+            {
+                mprf(MSGCH_ERROR, "error calling crawl.mpr (%s)", 
+                                  lua_tostring(ls, -1));
+            }
+//              mpr("got return values");
         }
     }
+    lua_settop(ls, 0); // clear stack
 }
 
 void debug_call_dlua()
 {
-    _debug_call_lua(dlua);
+    run_clua_interpreter(dlua);
 }
 
-- 
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