From d5df1b33144f92b6070e957db293e36b27e14439 Mon Sep 17 00:00:00 2001
From: Jed Barber <jjbarber@y7mail.com>
Date: Tue, 1 Dec 2020 16:04:17 +1100
Subject: Curtailing parser combinators implemented

---
 src/packrat-parsers.ads | 99 ++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 13 deletions(-)

(limited to 'src/packrat-parsers.ads')

diff --git a/src/packrat-parsers.ads b/src/packrat-parsers.ads
index 55cb12a..a5716f2 100644
--- a/src/packrat-parsers.ads
+++ b/src/packrat-parsers.ads
@@ -205,6 +205,18 @@ package Packrat.Parsers is
             Start   : in     Positive)
         return Combinator_Result;
 
+    generic
+        with function Param
+               (Input   : in     Traits.Element_Array;
+                Context : in out Parser_Context;
+                Start   : in     Positive)
+            return Combinator_Result;
+    function Optional
+           (Input   : in     Traits.Element_Array;
+            Context : in out Parser_Context;
+            Start   : in     Positive)
+        return Combinator_Result;
+
 
 
 
@@ -295,6 +307,18 @@ package Packrat.Parsers is
             Start   : in     Positive)
         return Combinator_Result;
 
+    generic
+        with function Combo
+               (Input   : in     Traits.Element_Array;
+                Context : in out Parser_Context;
+                Start   : in     Positive)
+            return Combinator_Result;
+    function Not_Empty
+           (Input   : in     Traits.Element_Array;
+            Context : in out Parser_Context;
+            Start   : in     Positive)
+        return Combinator_Result;
+
 
 private
 
@@ -358,9 +382,9 @@ private
 
 
     type Combo_Result_Part is record
-        Finish : Natural;
-        Value  : Elem_Holds.Holder;
-        Tokens : Tok_Holds.Holder;
+        Finish : Natural := 0;
+        Value  : Elem_Holds.Holder := Elem_Holds.Empty_Holder;
+        Tokens : Tok_Holds.Holder := Tok_Holds.Empty_Holder;
     end record;
 
     function "<"
@@ -386,10 +410,19 @@ private
 
     --  If there's anything in the Curtails, then Results should be empty
     --  and vice versa... union?
+
+    --  need to add an error string to percolate upwards for exceptions
+
+    --  need to add a record of the total length of input available when
+    --  result was computed, to allow for knowing when to recompute
+    --  optional_more/need_more results
+
+    --  actually no, just not putting optional/needmore results in the
+    --  memotable will work fine, but how to figure out how much to pass forward?
     type Combinator_Result is record
-        Results  : Result_Sets.Set;
-        Curtails : Curtail_Maps.Map;
-        Status   : Result_Status;
+        Results  : Result_Sets.Set := Result_Sets.Empty_Set;
+        Curtails : Curtail_Maps.Map := Curtail_Maps.Empty_Map;
+        Status   : Result_Status := Failure;
     end record;
 
     type Component_Result is record
@@ -458,17 +491,17 @@ private
 
 
     procedure Inc_Leftrec
-           (Key     : in     Combo_Key;
-            Context : in out Parser_Context);
+           (Key      : in     Combo_Key;
+            Leftrecs : in out Leftrectables.Map);
 
     procedure Dec_Leftrec
-           (Key     : in     Combo_Key;
-            Context : in out Parser_Context);
+           (Key      : in     Combo_Key;
+            Leftrecs : in out Leftrectables.Map);
 
     function Exceeds_Curtail
-           (Key     : in Combo_Key;
-            Context : in Parser_Context;
-            Input   : in Traits.Element_Array)
+           (Key      : in Combo_Key;
+            Leftrecs : in Leftrectables.Map;
+            Input    : in Traits.Element_Array)
         return Boolean;
 
     generic
@@ -482,6 +515,46 @@ private
         return Combinator_Result;
 
 
+
+
+    procedure Merge
+           (Target : in out Curtail_Maps.Map;
+            Add    : in     Curtail_Maps.Map);
+
+    function Merge
+           (Left, Right : in Curtail_Maps.Map)
+        return Curtail_Maps.Map;
+
+    --  Should only be used to merge results obtained from
+    --  the same input location.
+    procedure Merge
+           (Target : in out Combinator_Result;
+            Add    : in     Combinator_Result);
+
+    function Merge
+           (Left, Right : in Combinator_Result)
+        return Combinator_Result;
+
+    generic
+        with function Next
+               (Input   : in     Traits.Element_Array;
+                Context : in out Parser_Context;
+                Start   : in     Positive)
+            return Combinator_Result;
+    function Continue
+           (From    : in     Combinator_Result;
+            Input   : in     Traits.Element_Array;
+            Context : in out Parser_Context)
+        return Combinator_Result;
+
+
+
+
+    procedure Complete_Status
+           (Result : in out Combinator_Result;
+            Allow  : in     Boolean);
+
+
 end Packrat.Parsers;
 
 
-- 
cgit