Reimplemented 'print', channeled it through PrintBuffer

luprex/core/cpp/luastack.hpp

@@ -329,7 +329,7 @@ public:
         L_ = L;
         count_slots<0, 0, 0>(stackslots...);
         if (lua_gettop(L) < narg_) {
-            luaL_error(L, "not enough arguments on stack");
+            luaL_error(L, "not enough arguments to function");
         }
         assign_slots(argpos_, varpos_, retpos_, stackslots...);
         clear_frame();

luprex/core/cpp/pprint.cpp

@@ -5,20 +5,31 @@
 #include <iostream>
 
 
-LuaDefine(string_isidentifier, "c") {
-    LuaArg str;
-    LuaRet result;
-    LuaStack LS(L, str, result);
-    if (LS.isstring(str)) {
-        std::string s = LS.ckstring(str);
-        LS.set(result, util::is_identifier(s));
-    } else {
-        LS.set(result, false);
+void atomic_print(LuaStack &LS, LuaSlot val, std::ostream *os) {
+    switch (LS.type(val)) {
+    case LUA_TNIL:
+        (*os) << "nil";
+        return;
+    case LUA_TSTRING:
+        // TODO: this could be more efficient.
+        (*os) << LS.ckstring(val);
+        return;
+    case LUA_TNUMBER:
+        (*os) << LS.ckinteger(val);
+        return;
+    case LUA_TBOOLEAN:
+        (*os) << (LS.ckboolean(val) ? "true" : "false");
+        return;
+    case LUA_TTABLE:
+        (*os) << "table";
+        return;
+    default:
+        (*os) << "unknown";
+        return;
     }
-    return LS.result();
 }
 
-bool string_quote(LuaStack &LS, LuaSlot val, std::ostream *os) {
+static bool string_quote(LuaStack &LS, LuaSlot val, std::ostream *os) {
     switch (LS.type(val)) {
     case LUA_TNIL:
         (*os) << "nil";
@@ -37,15 +48,6 @@ bool string_quote(LuaStack &LS, LuaSlot val, std::ostream *os) {
     }
 }
 
-LuaDefine(string_quote, "c") {
-    LuaArg val;
-    LuaRet result;
-    LuaStack LS(L, val, result);
-    std::ostringstream oss;
-    string_quote(LS, val, &oss);
-    LS.set(result, oss.str());
-    return LS.result();
-}
 
 // Find tables recursively.
 //
@@ -242,6 +244,28 @@ void pprint(LuaStack &LS0, LuaSlot root, bool indent, std::ostream *os) {
     LS.result();
 }
 
+LuaDefine(string_isidentifier, "c") {
+    LuaArg str;
+    LuaRet result;
+    LuaStack LS(L, str, result);
+    if (LS.isstring(str)) {
+        std::string s = LS.ckstring(str);
+        LS.set(result, util::is_identifier(s));
+    } else {
+        LS.set(result, false);
+    }
+    return LS.result();
+}
+
+LuaDefine(string_print, "c") {
+    LuaArg val;
+    LuaRet result;
+    LuaStack LS(L, val, result);
+    std::ostringstream oss;
+    atomic_print(LS, val, &oss);
+    LS.set(result, oss.str());
+    return LS.result();
+}
 
 LuaDefine(string_pprint, "c") {
     LuaArg root, indent;
@@ -253,3 +277,13 @@ LuaDefine(string_pprint, "c") {
     LS.set(result, oss.str());
     return LS.result();
 }
+
+LuaDefine(string_tostring, "f") {
+    LuaArg val;
+    LuaRet result;
+    LuaStack LS(L, val, result);
+    std::ostringstream oss;
+    atomic_print(LS, val, &oss);
+    LS.set(result, oss.str());
+    return LS.result();
+}

luprex/core/cpp/pprint.hpp

@@ -1,24 +1,33 @@
-/////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////////////
 //
-// Pretty-print routine.
+// print, pprint, and tostring
 //
-// The pretty-printer can be called from C++ or Lua.
+// This module implements the heart of the lua 'print', lua 'pprint', and lua
+// 'tostring' functions. Note that we have to override the lua builtins 'print'
+// and 'tostring' for two reasons:
 //
-/////////////////////////////////////////////////////////
+//   * We need to suppress the printing of table addresses, for determinism.
+//   * We need to channel the output to a PrintBuffer in the world model.
+//
+// Note that the actual lua 'print' and 'pprint' routines aren't defined in this
+// module, they're in the World module, because they send their output into the
+// PrintBuffer of the world model.  But all the tricky code to implement 'print'
+// and 'pprint' are in this module.
+//
+//////////////////////////////////////////////////////////////////////////////////
 
 #ifndef PPRINT_HPP
 #define PPRINT_HPP
 
 #include "luastack.hpp"
 
-// Output a simple value to a stream.
+// Atomic print to a stream.
 //
-// If the value is a string, number, boolean, or nil, it is
-// quoted and output to the stream, and this function returns
-// true.  Otherwise, this function returns false and nothing
-// is sent to the stream.
+// This prints an atomic value to a stream.  If you give it a table,
+// it just prints "table".  This routine is the heart of the lua
+// primitives 'print' and 'tostring'.
 //
-bool string_quote(LuaStack &LS, LuaSlot val, std::ostream *os);
+void atomic_print(LuaStack &LS, LuaSlot val, std::ostream *os);
 
 // Pretty print to a stream.
 //
@@ -30,17 +39,4 @@ bool string_quote(LuaStack &LS, LuaSlot val, std::ostream *os);
 //
 void pprint(LuaStack &LS, LuaSlot val, bool indent, std::ostream *os);
 
-// The following lua interfaces to this code are included:
-//
-// pprint(expr, expr, expr...)
-//
-// - pretty print the specified expression to stdout.
-//
-// string.pprint(expr, indent)
-//
-// - pretty print the specified expression, return the result as a string.
-//
-int lfn_pprint_pprint(lua_State *L);
-int lfn_string_pprint(lua_State *L);
-
 #endif // PPRINT_HPP

luprex/core/cpp/world-accessor.cpp

@@ -220,4 +220,16 @@ LuaDefine(world_pprint, "f") {
         (*ostream) << std::endl;
     }
     return LS.result();
+}
+
+LuaDefine(world_print, "f") {
+    World *w = World::fetch_global_pointer(L);
+    std::ostream *ostream = w->lthread_print_stream();
+    LuaStack LS(L);
+    for (int i = 1; i <= lua_gettop(L); i++) {
+        LuaSpecial root(i);
+        atomic_print(LS, root, ostream);
+        (*ostream) << std::endl;
+    }
+    return LS.result();
 }