From 78ef41756edd3e6927436dcd8bc15a62598f6a3e Mon Sep 17 00:00:00 2001
From: Ryan Hendrickson <ryan.hendrickson@alum.mit.edu>
Date: Wed, 10 Feb 2016 12:27:03 -0500
Subject: [PATCH] fix semiautovivification with slices

---
 lib/ast.js       | 16 +++++++++++++---
 src/ast.ls       | 10 ++++++++--
 test/chaining.ls |  5 +++++
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/lib/ast.js b/lib/ast.js
index 9ba2f4b05..37b4229eb 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -955,7 +955,7 @@ exports.Chain = Chain = (function(superclass){
   } function ctor$(){} ctor$.prototype = prototype;
   prototype.children = ['head', 'tails'];
   prototype.add = function(it){
-    var last, ref$, index, ref1$, bi, that, ref2$, logics, call, f;
+    var last, ref$, index, ref1$, bi, logics, call, f;
     if (this.tails.length) {
       last = (ref$ = this.tails)[ref$.length - 1];
       if (last instanceof Call && ((ref$ = last.partialized) != null ? ref$.length : void 8) === 1 && it.args.length === 1) {
@@ -981,8 +981,6 @@ exports.Chain = Chain = (function(superclass){
       } else if (!this.tails[1] && ((ref1$ = it.key) != null ? ref1$.name : void 8) === 'prototype') {
         this.head.sproto = true;
       }
-    } else if (that = (ref2$ = it.vivify, delete it.vivify, ref2$)) {
-      this.head = Assign(Chain(this.head, this.tails.splice(0, 9e9)), that(), '=', '||');
     } else if (it instanceof Call && this.tails.length === 1 && bi && in$(bi.op, logics = ['&&', '||', 'xor'])) {
       call = it;
       f = function(x, key){
@@ -1161,6 +1159,7 @@ exports.Chain = Chain = (function(superclass){
       this.carp('invalid callee');
     }
     this.expandSlice(o);
+    this.expandVivify();
     this.expandBind(o);
     this.expandSplat(o);
     this.expandStar(o);
@@ -1272,6 +1271,17 @@ exports.Chain = Chain = (function(superclass){
       }
     }
   };
+  prototype.expandVivify = function(){
+    var tails, i, that, ref$, ref1$;
+    tails = this.tails;
+    i = 0;
+    while (i < tails.length) {
+      if (that = (ref1$ = (ref$ = tails[i++]).vivify, delete ref$.vivify, ref1$)) {
+        this.head = Assign(Chain(this.head, tails.splice(0, i)), that(), '=', '||');
+        i = 0;
+      }
+    }
+  };
   prototype.expandBind = function(o){
     var tails, i, that, obj, key, call;
     tails = this.tails;
diff --git a/src/ast.ls b/src/ast.ls
index cb37e78d0..ea3d690b8 100644
--- a/src/ast.ls
+++ b/src/ast.ls
@@ -639,8 +639,6 @@ class exports.Chain extends Node
                 @head.called = true
             else if not @tails.1 and it.key?name is \prototype
                 @head.sproto = true
-        else if delete it.vivify
-            @head = Assign Chain(@head, @tails.splice 0, 9e9), that!, \= \||
         else if it instanceof Call and @tails.length is 1
         and bi and bi.op in logics = <[ && || xor ]>
             call = it
@@ -759,6 +757,7 @@ class exports.Chain extends Node
                 .add Call [context, Arr [this; Arr partial.args; Arr partial.partialized]]), post).compile o
         @carp 'invalid callee' if tails.0 instanceof Call and not head.is-callable!
         @expand-slice o
+        @expand-vivify!
         @expand-bind o
         @expand-splat o
         @expand-star o
@@ -837,6 +836,13 @@ class exports.Chain extends Node
                     i = 0
                 call <<< method: \.apply, args: [ctx or Literal \null; JS args]
 
+    expand-vivify: !->
+        {tails} = this
+        i = 0
+        while i < tails.length when delete tails[i++]vivify
+            @head = Assign Chain(@head, tails.splice 0, i), that!, \= \||
+            i = 0
+
     expand-bind: !(o) ->
         {tails} = this
         i = -1
diff --git a/test/chaining.ls b/test/chaining.ls
index ac78704a4..04686d424 100644
--- a/test/chaining.ls
+++ b/test/chaining.ls
@@ -214,6 +214,11 @@ eq '0,1' ''+o.a.b
 eq '2,3' ''+o.a.c.d
 eq 5 o.a.b.e.f.4
 
+a = []
+eq 2 a{}[0, 1].length
+eq \object typeof a.0
+eq \object typeof a.1
+
 # Bang Call
 eq '' String!
 (-> ok true)!