Fixed issue #101. Incorrect shift/reduce conflict resolution

8 files changed, 41 insertions, 15 deletions

diff --git a/ANNOUNCE b/ANNOUNCE
index 15fcb41..79ffebd 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,11 +1,11 @@
-August 31, 2016
+October 7, 2016
 
-                  Announcing :  PLY-3.9 (Python Lex-Yacc)
+                  Announcing :  PLY-3.10 (Python Lex-Yacc)
 
                         http://www.dabeaz.com/ply
 
-I'm pleased to announce PLY-3.9--a pure Python implementation of the
-common parsing tools lex and yacc.  PLY-3.9 is a minor bug fix
+I'm pleased to announce PLY-3.10--a pure Python implementation of the
+common parsing tools lex and yacc.  PLY-3.10 is a minor bug fix
 release.  It supports both Python 2 and Python 3.
 
 If you are new to PLY, here are a few highlights:
diff --git a/CHANGES b/CHANGES
index 75cba86..a974a7c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,19 @@
+Version 3.10
+---------------------
+10/07/16: beazley
+          Fixed Issue #101: Incorrect shift-reduce conflict resolution with
+          precedence specifier.
+
+          PLY was incorrectly resolving shift-reduce conflicts in certain
+          cases.  For example, in the example/calc/calc.py example, you 
+          could trigger it doing this:
+
+          calc > -3 - 4            
+          1                         (correct answer should be -7)
+          calc >
+
+          Issue and suggested patch contributed by https://github.com/RomaVis
+           
 Version 3.9
 ---------------------
 08/30/16: beazley
diff --git a/README.md b/README.md
index 402ffba..7563583 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-PLY (Python Lex-Yacc)                   Version 3.9
+PLY (Python Lex-Yacc)                   Version 3.10
 
 Copyright (C) 2001-2016
 David M. Beazley (Dabeaz LLC)
diff --git a/doc/internal.html b/doc/internal.html
index 3fabfe2..f73bc43 100644
--- a/doc/internal.html
+++ b/doc/internal.html
@@ -12,7 +12,7 @@ dave@dabeaz.com<br>
 </b>
 
 <p>
-<b>PLY Version: 3.0</b>
+<b>PLY Version: 3.10</b>
 <p>
 
 <!-- INDEX -->
diff --git a/doc/ply.html b/doc/ply.html
index 70a4152..0b232b2 100644
--- a/doc/ply.html
+++ b/doc/ply.html
@@ -12,7 +12,7 @@ dave@dabeaz.com<br>
 </b>
 
 <p>
-<b>PLY Version: 3.9</b>
+<b>PLY Version: 3.10</b>
 <p>
 
 <!-- INDEX -->
diff --git a/ply/lex.py b/ply/lex.py
index 0f3e464..f548622 100644
--- a/ply/lex.py
+++ b/ply/lex.py
@@ -31,8 +31,8 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 # -----------------------------------------------------------------------------
 
-__version__    = '3.9'
-__tabversion__ = '3.8'
+__version__    = '3.10'
+__tabversion__ = '3.10'
 
 import re
 import sys
diff --git a/ply/yacc.py b/ply/yacc.py
index 6842832..62ebc88 100644
--- a/ply/yacc.py
+++ b/ply/yacc.py
@@ -67,8 +67,8 @@ import inspect
 import base64
 import warnings
 
-__version__    = '3.9'
-__tabversion__ = '3.8'
+__version__    = '3.10'
+__tabversion__ = '3.10'
 
 #-----------------------------------------------------------------------------
 #                     === User configurable parameters ===
@@ -2585,8 +2585,13 @@ class LRGeneratedTable(LRTable):
                                         # Need to decide on shift or reduce here
                                         # By default we favor shifting. Need to add
                                         # some precedence rules here.
-                                        sprec, slevel = Productions[st_actionp[a].number].prec
-                                        rprec, rlevel = Precedence.get(a, ('right', 0))
+
+                                        # Shift precedence comes from the token
+                                        sprec, slevel = Precedence.get(a, ('right', 0))
+
+                                        # Reduce precedence comes from rule being reduced (p)
+                                        rprec, rlevel = Productions[p.number].prec
+
                                         if (slevel < rlevel) or ((slevel == rlevel) and (rprec == 'left')):
                                             # We really need to reduce here.
                                             st_action[a] = -p.number
@@ -2644,8 +2649,13 @@ class LRGeneratedTable(LRTable):
                                         #   -  if precedence of reduce rule is higher, we reduce.
                                         #   -  if precedence of reduce is same and left assoc, we reduce.
                                         #   -  otherwise we shift
-                                        rprec, rlevel = Productions[st_actionp[a].number].prec
+
+                                        # Shift precedence comes from the token
                                         sprec, slevel = Precedence.get(a, ('right', 0))
+
+                                        # Reduce precedence comes from the rule that could have been reduced
+                                        rprec, rlevel = Productions[st_actionp[a].number].prec
+
                                         if (slevel > rlevel) or ((slevel == rlevel) and (rprec == 'right')):
                                             # We decide to shift here... highest precedence to shift
                                             Productions[st_actionp[a].number].reduced -= 1
diff --git a/setup.py b/setup.py
index 948e2cf..ee8ccd0 100644
--- a/setup.py
+++ b/setup.py
@@ -17,7 +17,7 @@ PLY is extremely easy to use and provides very extensive error checking.
 It is compatible with both Python 2 and Python 3.
 """,
             license="""BSD""",
-            version = "3.9",
+            version = "3.10",
             author = "David Beazley",
             author_email = "dave@dabeaz.com",
             maintainer = "David Beazley",