Array unshift

brownplt · Aug 7, 2011 · efa5c4f · efa5c4f
1 parent 958066d
commit efa5c4f
Showing 1 changed file with 51 additions and 3 deletions.
diff --git a/envs/es5.env b/envs/es5.env
@@ -822,7 +822,8 @@ let [[%RangeErrorGlobalFuncObj]] =
 
 {%RangeErrorProto["constructor" = %RangeErrorGlobalFuncObj]}
 
-let [[%ArrayProto]] = { [#proto : %ObjectProto, #class : "Array",] }
+let [[%ArrayProto]] = { [#proto : %ObjectProto, #class : "Array",]
+  "length" : {#value 0, #writable true} }
 
 let [[%ToUint32]] = func(n) {
   let (number = %ToNumber(n))
@@ -1506,6 +1507,53 @@ let [[%splice]] = {[#code : %splicelambda, #proto : %FunctionProto,]}
   {[] "value" : {#value %splice, #writable true},
       "configurable" : {#value true, #writable true}}) }
 
+let [[%unshiftlambda]] = func(this, args) {
+  let (O = %ToObject(this))
+  let (lenVal = O["length"])
+  let (len = %ToUint32(lenVal))
+  let (argCount = args["length"])
+
+  rec (Oloop = func(k) {
+    if (prim(">", k, 0)) {
+      let (from = %ToString(prim("-", k, 1)))
+      let (to = %ToString(prim("+", k, prim("-", argCount, 1))))
+      if (prim("hasProperty", O, from)) {
+        O[to = O[from] ];
+        Oloop(prim("-", k, 1))
+      } else { 
+        O[delete to];
+        Oloop(prim("-", k, 1))
+      }
+    } else { undefined }
+  })
+  Oloop(len);
+
+  let (end = args["length"])
+  rec (argsLoop = func(argsIndex, j) {
+    if (prim("<", argsIndex, end)) {
+      O[%ToString(j) = args[prim("prim->str", argsIndex)] ];
+      argsLoop(prim("+", argsIndex, 1), prim("+", j, 1))
+    } else { undefined }
+  })
+  argsLoop(0, 0);
+
+  let (finalLen = prim("+", len, argCount))
+  O["length" = finalLen];
+  finalLen
+}
+
+let [[%unshift]] = {[#code : %unshiftlambda, #proto : %FunctionProto,]}
+
+{%defineOwnProperty(%unshift,
+  "length",
+  {[] "value" : {#value 1, #writable true},
+      "enumerable" : {#value false, #writable true}}) }
+
+{%defineOwnProperty(%ArrayProto,
+  "unshift",
+  {[] "value" : {#value %unshift, #writable true},
+      "configurable" : {#value true, #writable true}}) }
+
 let [[%slicelambda]] = func(this, args) {
   let (O = %ToObject(this))
   let (A = {[#proto : %ArrayProto, #class : "Array",]})
@@ -1783,15 +1831,15 @@ let [[%set-property]] = func(obj, fld, val) {
       }
   })
   let (setArrayField = func() {
+    obj[fld = val];
     if (isArrayIndex()) {
       let (uint = %ToUint32(fld))
       let (len = obj[fld])
       if (prim("<", len, prim("+", uint, 1))) {
         obj["length" = prim("+", uint, 1)]
       } else { undefined }
     }
-    else { undefined };
-    obj[fld = val]
+    else { undefined }
   })
   if (prim("get-class", obj) === "Array") {
     setArrayField()