From 4bf190d1b51c8c2d3f5ab0b6355ecd971b735adc Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <giann008@gmail.com>
Date: Sat, 11 Feb 2017 22:22:38 +0100
Subject: TFORCALL, TFORLOOP, luaD_call, tag methods

---
 src/ldo.js | 81 ++++++++++++++++++++++++++++----------------------------------
 1 file changed, 36 insertions(+), 45 deletions(-)

(limited to 'src/ldo.js')

diff --git a/src/ldo.js b/src/ldo.js
index 488bc86..85bd3d3 100644
--- a/src/ldo.js
+++ b/src/ldo.js
@@ -1,23 +1,21 @@
 /*jshint esversion: 6 */
 "use strict";
 
-const OC             = require('./lopcodes.js');
 const lua            = require('./lua.js');
 const CT             = lua.constant_types;
 const LUA_MULTRET    = lua.LUA_MULTRET;
 const lobject        = require('./lobject.js');
 const TValue         = lobject.TValue;
-const Table          = lobject.Table;
-const LClosure       = lobject.LClosure;
-const lfunc          = require('./lfunc.js');
-const UpVal          = lfunc.UpVal;
 const lstate         = require('./lstate.js');
 const CallInfo       = lstate.CallInfo;
 const llimit         = require('./llimit.js');
+const ltm            = require('./ltm.js');
+const TMS            = ltm.TMS;
 
 const nil            = new TValue(CT.LUA_TNIL, null);
 
-const precall = function(L, off, func, nresults) {
+const luaD_precall = function(L, off, nresults) {
+    let func = L.stack[off];
     let ci;
 
     switch(func.type) {
@@ -56,28 +54,30 @@ const precall = function(L, off, func, nresults) {
             }
             ci.nresults = nresults;
             ci.func = func;
+            ci.funcOff = off;
             ci.u.l.base = base;
             ci.top = base + fsize;
             L.top = ci.top;
             ci.u.l.savedpc = p.code;
+            ci.pcOff = 0;
             ci.callstatus = lstate.CIST_LUA;
 
             return false;
             break;
         }
         default:
-            // __call
-            return false;
+            tryfuncTM(L, off, func);
+            return luaD_precall(L, off, nresults);
     }
-}
+};
 
-const postcall = function(L, ci, firstResult, nres) {
+const luaD_poscall = function(L, ci, firstResult, nres) {
     let wanted = ci.nresults;
     let res = ci.funcOff;
     L.ci = ci.previous;
     L.ciOff--;
     return moveresults(L, firstResult, res, nres, wanted);
-}
+};
 
 const moveresults = function(L, firstResult, res, nres, wanted) {
     switch (wanted) {
@@ -98,7 +98,11 @@ const moveresults = function(L, firstResult, res, nres, wanted) {
         default: {
             let i;
             if (wanted <= nres) {
-                for (i = 0; i < wanted; i++)
+                for (i = 0; i < wanted; i++) {
+                    L.stack[res + i] = L.stack[firstResult + i];
+                }
+            } else {
+                for (i = 0; i < nres; i++)
                     L.stack[res + i] = L.stack[firstResult + i];
                 for (; i < wanted; i++)
                     L.stack[res + i] = nil;
@@ -107,8 +111,9 @@ const moveresults = function(L, firstResult, res, nres, wanted) {
         }
     }
 
+    L.top = res + wanted; /* top points after the last result */
     return true;
-}
+};
 
 const adjust_varargs = function(L, p, actual) {
     let nfixargs = p.numparams;
@@ -126,38 +131,24 @@ const adjust_varargs = function(L, p, actual) {
         L.stack[L.top++] = nil;
 
     return base;
+};
+
+const tryfuncTM = function(L, off, func) {
+    let tm = ltm.luaT_gettmbyobj(L, func, TMS.TM_CALL);
+    if (!tm.ttisfunction(tm))
+        throw new Error("__call metatable member is not a function") // TODO: luaG_typeerror
+    /* Open a hole inside the stack at 'func' */
+    for (p = L.top; p > off; p--)
+        L.stack[p] = L.stack[p-1];
+    L.top++; /* slot ensured by caller */
+    L.stack[off] = tm; /* tag method is the new function to be called */       
 }
 
-
-/*
-** Check appropriate error for stack overflow ("regular" overflow or
-** overflow while handling stack overflow). If 'nCalls' is larger than
-** LUAI_MAXCCALLS (which means it is handling a "regular" overflow) but
-** smaller than 9/8 of LUAI_MAXCCALLS, does not report an error (to
-** allow overflow handling to work)
-*/
-const stackerror = function(L) {
-    if (L.nCcalls === LUAI_MAXCCALLS)
-        throw new Error("JS stack overflow");
-    else if (L.nCcalls >= (LUAI_MAXCCALLS + (LUAI_MAXCCALLS>>3))) /* error while handing stack error */
-        throw new Error("stack overflow") // TODO: luaD_throw(L, LUA_ERRERR);
-}
-
-/*
-** Call a function (JS or Lua). The function to be called is at func.
-** The arguments are on the stack, right after the function.
-** When returns, all the results are on the stack, starting at the original
-** function position.
-*/
-// const luaD_call = function(L, func, nResults) {
-//     if (++L->nCcalls >= LUAI_MAXCCALLS)
-//         stackerror(L);
-//     if ()
-// }
-
 module.exports = {
-    precall:        precall,
-    postcall:       postcall,
-    moveresults:    moveresults,
-    adjust_varargs: adjust_varargs
-}
\ No newline at end of file
+    nil:              nil,
+    luaD_precall:     luaD_precall,
+    luaD_poscall:     luaD_poscall,
+    moveresults:      moveresults,
+    adjust_varargs:   adjust_varargs,
+    tryfuncTM:        tryfuncTM
+};
\ No newline at end of file
-- 
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