1 files changed, 217 insertions, 0 deletions
diff --git a/ext/ply/example/yply/yparse.py b/ext/ply/example/yply/yparse.py
new file mode 100644
index 000000000..a4e46bef7
--- /dev/null
+++ b/ext/ply/example/yply/yparse.py
@@ -0,0 +1,217 @@
+# parser for Unix yacc-based grammars
+#
+# Author: David Beazley (dave@dabeaz.com)
+# Date  : October 2, 2006
+
+import ylex
+tokens = ylex.tokens
+
+from ply import *
+
+tokenlist = []
+preclist  = []
+
+emit_code = 1
+
+def p_yacc(p):
+    '''yacc : defsection rulesection'''
+
+def p_defsection(p):
+    '''defsection : definitions SECTION
+                  | SECTION'''
+    p.lexer.lastsection = 1
+    print "tokens = ", repr(tokenlist)
+    print
+    print "precedence = ", repr(preclist)
+    print
+    print "# -------------- RULES ----------------"
+    print
+
+def p_rulesection(p):
+    '''rulesection : rules SECTION'''
+
+    print "# -------------- RULES END ----------------"
+    print_code(p[2],0)
+
+def p_definitions(p):
+    '''definitions : definitions definition
+                   | definition'''
+
+def p_definition_literal(p):
+    '''definition : LITERAL'''
+    print_code(p[1],0)
+
+def p_definition_start(p):
+    '''definition : START ID'''
+    print "start = '%s'" % p[2]
+
+def p_definition_token(p):
+    '''definition : toktype opttype idlist optsemi '''
+    for i in p[3]:
+       if i[0] not in "'\"":
+           tokenlist.append(i)
+    if p[1] == '%left':
+        preclist.append(('left',) + tuple(p[3]))
+    elif p[1] == '%right':
+        preclist.append(('right',) + tuple(p[3]))
+    elif p[1] == '%nonassoc':
+        preclist.append(('nonassoc',)+ tuple(p[3]))
+
+def p_toktype(p):
+    '''toktype : TOKEN
+               | LEFT
+               | RIGHT
+               | NONASSOC'''
+    p[0] = p[1]
+
+def p_opttype(p):
+    '''opttype : '<' ID '>'
+               | empty'''
+
+def p_idlist(p):
+    '''idlist  : idlist optcomma tokenid
+               | tokenid'''
+    if len(p) == 2:
+        p[0] = [p[1]]
+    else:
+        p[0] = p[1]
+        p[1].append(p[3])
+
+def p_tokenid(p):
+    '''tokenid : ID
+               | ID NUMBER
+               | QLITERAL
+               | QLITERAL NUMBER'''
+    p[0] = p[1]
+
+def p_optsemi(p):
+    '''optsemi : ';'
+               | empty'''
+
+def p_optcomma(p):
+    '''optcomma : ','
+                | empty'''
+
+def p_definition_type(p):
+    '''definition : TYPE '<' ID '>' namelist optsemi'''
+    # type declarations are ignored
+
+def p_namelist(p):
+    '''namelist : namelist optcomma ID
+                | ID'''
+
+def p_definition_union(p):
+    '''definition : UNION CODE optsemi'''
+    # Union declarations are ignored
+
+def p_rules(p):
+    '''rules   : rules rule
+               | rule'''
+    if len(p) == 2:
+       rule = p[1]
+    else:
+       rule = p[2]
+
+    # Print out a Python equivalent of this rule
+
+    embedded = [ ]      # Embedded actions (a mess)
+    embed_count = 0
+
+    rulename = rule[0]
+    rulecount = 1
+    for r in rule[1]:
+        # r contains one of the rule possibilities
+        print "def p_%s_%d(p):" % (rulename,rulecount)
+        prod = []
+        prodcode = ""
+        for i in range(len(r)):
+             item = r[i]
+             if item[0] == '{':    # A code block
+                  if i == len(r) - 1:
+                      prodcode = item
+                      break
+                  else:
+                      # an embedded action
+                      embed_name = "_embed%d_%s" % (embed_count,rulename)
+                      prod.append(embed_name)
+                      embedded.append((embed_name,item))
+                      embed_count += 1
+             else:
+                  prod.append(item)
+        print "    '''%s : %s'''" % (rulename, " ".join(prod))
+        # Emit code
+        print_code(prodcode,4)
+        print
+        rulecount += 1
+
+    for e,code in embedded:
+        print "def p_%s(p):" % e
+        print "    '''%s : '''" % e
+        print_code(code,4)
+        print
+
+def p_rule(p):
+   '''rule : ID ':' rulelist ';' '''
+   p[0] = (p[1],[p[3]])
+
+def p_rule2(p):
+   '''rule : ID ':' rulelist morerules ';' '''
+   p[4].insert(0,p[3])
+   p[0] = (p[1],p[4])
+
+def p_rule_empty(p):
+   '''rule : ID ':' ';' '''
+   p[0] = (p[1],[[]])
+
+def p_rule_empty2(p):
+   '''rule : ID ':' morerules ';' '''
+
+   p[3].insert(0,[])
+   p[0] = (p[1],p[3])
+
+def p_morerules(p):
+   '''morerules : morerules '|' rulelist
+                | '|' rulelist
+                | '|'  '''
+
+   if len(p) == 2:
+       p[0] = [[]]
+   elif len(p) == 3:
+       p[0] = [p[2]]
+   else:
+       p[0] = p[1]
+       p[0].append(p[3])
+
+#   print "morerules", len(p), p[0]
+
+def p_rulelist(p):
+   '''rulelist : rulelist ruleitem
+               | ruleitem'''
+
+   if len(p) == 2:
+        p[0] = [p[1]]
+   else:
+        p[0] = p[1]
+        p[1].append(p[2])
+
+def p_ruleitem(p):
+   '''ruleitem : ID
+               | QLITERAL
+               | CODE
+               | PREC'''
+   p[0] = p[1]
+
+def p_empty(p):
+    '''empty : '''
+
+def p_error(p):
+    pass
+
+yacc.yacc(debug=0)
+
+def print_code(code,indent):
+    if not emit_code: return
+    codelines = code.splitlines()
+    for c in codelines:
+         print "%s# %s" % (" "*indent,c)
+