[PATCH for Dlang support 1/2] d: add yyerrok()

In D's case, yyerrok() is a private method of the Parser class.
However, it can be called directly as `yyerrok()` from the grammar rules section.

The examples were modified to demonstrate this functionality.

* data/skeletons/lalr1.d: Add yyerrok().
* examples/d/calc/calc.y, examples/d/simple/calc.y: Demonstrate yyerrok().
* tests/calc.at: Update D tests to use yyerrok().
---
 data/skeletons/lalr1.d   | 5 +++++
 examples/d/calc/calc.y   | 2 +-
 examples/d/simple/calc.y | 2 +-
 tests/calc.at            | 2 +-
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/data/skeletons/lalr1.d b/data/skeletons/lalr1.d
index 9b7c786c..8e464907 100644
--- a/data/skeletons/lalr1.d
+++ b/data/skeletons/lalr1.d
@@ -307,6 +307,11 @@ b4_user_union_members
   private static immutable YYSemanticType yy_semantic_null;])[
   private int yyerrstatus_ = 0;
 
+  private void yyerrok()
+  {
+    yyerrstatus_ = 0;
+  }
+
   /**
    * Whether error recovery is being done.  In this state, the parser
    * reads token until it reaches a known state, and then restarts normal
diff --git a/examples/d/calc/calc.y b/examples/d/calc/calc.y
index 9fea82cd..98ec06c0 100644
--- a/examples/d/calc/calc.y
+++ b/examples/d/calc/calc.y
@@ -53,7 +53,7 @@ input:
 line:
   EOL
 | exp EOL           { writeln ($exp); }
-| error EOL
+| error EOL         { yyerrok(); }
 ;
 
 exp:
diff --git a/examples/d/simple/calc.y b/examples/d/simple/calc.y
index 0f441431..41800080 100644
--- a/examples/d/simple/calc.y
+++ b/examples/d/simple/calc.y
@@ -51,7 +51,7 @@ input:
 line:
   EOL
 | exp EOL           { writeln ($exp); }
-| error EOL
+| error EOL         { yyerrok(); }
 ;
 
 exp:
diff --git a/tests/calc.at b/tests/calc.at
index 94a5fdb0..139cc5c5 100644
--- a/tests/calc.at
+++ b/tests/calc.at
@@ -720,7 +720,7 @@ exp:
 | "-" exp  %prec NEG { $$ = -$2; }
 | exp "^" exp        { $$ = power ($1, $3); }
 | "(" exp ")"        { $$ = $2; }
-| "(" error ")"      { $$ = 1111; }
+| "(" error ")"      { $$ = 1111; yyerrok(); }
 | "!"                { $$ = 0; return YYERROR; }
 | "-" error          { $$ = 0; return YYERROR; }
 ;
-- 
2.17.1