From 1138898989fa6b0153b7a00a1af3b37e07947219 Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Sat, 30 Sep 2017 02:34:56 +0200
Subject: [PATCH] UI-Coordinates: implement indexed access

...under the assumption that the content is normalised,
which means
- leading NULL is changed to Symbol::EMPTY
- missing elements in the middle are marked as "*"
- trailing NULL in extension storage is handled by adjusting nominal extension size
---
 src/lib/path-array.hpp               | 24 ++++++++++++++++++++++--
 src/lib/symbol-impl.cpp              |  1 +
 src/lib/symbol.hpp                   |  1 +
 tests/gui/interact/ui-coord-test.cpp |  5 +++--
 tests/library/path-array-test.cpp    | 11 +++++++----
 5 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/src/lib/path-array.hpp b/src/lib/path-array.hpp
index 506c5fa18..ffe36cc9a 100644
--- a/src/lib/path-array.hpp
+++ b/src/lib/path-array.hpp
@@ -50,6 +50,7 @@
 #include "lib/symbol.hpp"
 #include "lib/iter-adapter.hpp"
 #include "lib/meta/variadic-helper.hpp"
+#include "lib/format-obj.hpp"
 #include "lib/util.hpp"
 
 //#include <boost/noncopyable.hpp>
@@ -61,6 +62,7 @@
 
 
 namespace lib {
+  namespace error = lumiera::error;
   
 //  using std::unique_ptr;
   using std::forward;
@@ -164,6 +166,13 @@ namespace lib {
             return storage_? size(unConst(this)->storage_)
                            : 0;
           }
+        
+        const char*
+        operator[] (size_t idx)  const
+          {
+            REQUIRE (storage_ and idx < size());
+            return storage_[1+idx];
+          }
       };
   }//(End)Implementation helper
   
@@ -249,7 +258,7 @@ namespace lib {
       bool
       empty()  const
         {
-          UNIMPLEMENTED ("path implementation storage");
+          return not elms_[0]; // normalise() ensures this holds only for empty paths
         }
       
       operator string()  const;
@@ -258,7 +267,18 @@ namespace lib {
       Literal
       operator[] (size_t idx)
         {
-          UNIMPLEMENTED ("path implementation storage");
+          Lit elm{0};
+          if (idx < chunk_size)
+            elm = elms_[idx];
+          else
+          if (idx-chunk_size < tail_.size())
+            elm = tail_[idx-chunk_size];
+          
+          if (not elm)
+            throw error::Invalid ("Accessing index "+util::toString(idx)
+                                 +" on PathArray of size "+ util::toString(size())
+                                 ,error::LUMIERA_ERROR_INDEX_BOUNDS);
+          return elm;
         }
       
       
diff --git a/src/lib/symbol-impl.cpp b/src/lib/symbol-impl.cpp
index c616ce7c2..47c410634 100644
--- a/src/lib/symbol-impl.cpp
+++ b/src/lib/symbol-impl.cpp
@@ -82,6 +82,7 @@ namespace lib {
   
   
   /* == predefined marker Symbols == */
+  Symbol Symbol::EMPTY   = "";
   Symbol Symbol::BOTTOM  = "⟂";
   Symbol Symbol::FAILURE = "↯";
   
diff --git a/src/lib/symbol.hpp b/src/lib/symbol.hpp
index c6abfd856..1627a3af9 100644
--- a/src/lib/symbol.hpp
+++ b/src/lib/symbol.hpp
@@ -93,6 +93,7 @@ namespace lib {
     : public Literal
     {
     public:
+      static Symbol EMPTY;
       static Symbol BOTTOM;
       static Symbol FAILURE;
       
diff --git a/tests/gui/interact/ui-coord-test.cpp b/tests/gui/interact/ui-coord-test.cpp
index 4f2b77345..9d0786c3a 100644
--- a/tests/gui/interact/ui-coord-test.cpp
+++ b/tests/gui/interact/ui-coord-test.cpp
@@ -41,6 +41,7 @@ using std::string;
 //using lib::idi::EntryID;
 //using lib::diff::GenNode;
 //using util::isSameObject;
+using lib::Symbol;
 using util::isnil;
 using util::join;
 
@@ -126,8 +127,8 @@ namespace test {
           
           // representation is trimmed and filled
           CHECK ("UI:Θ.*.*/*/Φ" == string(uic));
-          CHECK (NULL == uic[UIC_WINDOW]);
-          CHECK (NULL == uic[UIC_PERSP]);
+          CHECK (Symbol::EMPTY == uic[UIC_WINDOW]);
+          CHECK (Symbol::EMPTY == uic[UIC_PERSP]);
           CHECK ("Θ" == uic[UIC_PANEL]);
           CHECK ("*" == uic[UIC_VIEW]);
           CHECK ("*" == uic[UIC_TAB]);
diff --git a/tests/library/path-array-test.cpp b/tests/library/path-array-test.cpp
index e2cbb3ad2..0fa3456ce 100644
--- a/tests/library/path-array-test.cpp
+++ b/tests/library/path-array-test.cpp
@@ -41,6 +41,7 @@ using std::string;
 //using lib::idi::EntryID;
 //using lib::diff::GenNode;
 //using util::isSameObject;
+using lib::Symbol;
 using util::isnil;
 using util::join;
 
@@ -111,8 +112,8 @@ namespace test {
           
           // representation is trimmed and filled
           CHECK ("Θ/*/*/*/Φ" == string(parr));
-          CHECK (NULL == parr[0]);
-          CHECK (NULL == parr[1]);
+          CHECK (Symbol::EMPTY == parr[0]);
+          CHECK (Symbol::EMPTY == parr[1]);
           CHECK ("Θ" ==  parr[2]);
           CHECK ("*" ==  parr[3]);
           CHECK ("*" ==  parr[4]);
@@ -158,8 +159,10 @@ namespace test {
           
           // index numbering starts at absolute root
           CHECK ("Ω" == *parr.begin());
-          CHECK (nullptr == parr[0]);
-          CHECK ("Ω"     == parr[15]);
+          CHECK (Symbol::EMPTY == parr[0]);
+          CHECK (Symbol::EMPTY == parr[1]);
+          CHECK (Symbol::EMPTY == parr[2]);
+          CHECK ("Ω"           == parr[15]);
           VERIFY_ERROR (INDEX_BOUNDS, parr[16]);
         }