From 980188d90cc8ff8f211d82919f4482f7aaa5b567 Mon Sep 17 00:00:00 2001
From: hellerve <veit@veitheller.de>
Date: Mon, 27 Feb 2017 18:08:11 +0100
Subject: [PATCH] added memoization for a factor 100 speed improvement

---
 examples/golike.py |  4 ++--
 gll/parser.py      | 15 ++++++++++++++-
 gll/util.py        | 12 ++++++++++++
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/examples/golike.py b/examples/golike.py
index f9f8ebd..61b5a34 100644
--- a/examples/golike.py
+++ b/examples/golike.py
@@ -48,8 +48,8 @@ package_name = gll.seq(skipped("package"), ws, variable,
                        gll.skipmany(gll.string(" ")), skipped("\n"),
                        tag="package_name")
 
-package = gll.seq(package_name, gll.sep_by(gll.string("\n"), function,
-                                           tag="package_body"),
+package = gll.seq(package_name, gll.many(skipped("\n")),
+                  gll.sep_by(gll.string("\n"), function, tag="package_body"),
                   gll.many(skipped("\n")),
                   tag="package")
 
diff --git a/gll/parser.py b/gll/parser.py
index 6128e1d..0e8686a 100644
--- a/gll/parser.py
+++ b/gll/parser.py
@@ -1,6 +1,6 @@
 import re
 
-from gll.util   import rename
+from gll.util   import rename, memoize
 from gll.result import Success, Failure
 
 class Parser:
@@ -16,6 +16,7 @@ class Parser:
         return self.fun.__name__
 
     def __or__(self, other):
+        @memoize
         @rename("{}_alt_{}".format(self.name, other.name))
         def internal(string):
             res = self(string)
@@ -26,6 +27,7 @@ class Parser:
         return Parser(internal)
 
     def __rshift__(self, into):
+        @memoize
         @rename("{}_into_{}".format(self.name, into))
         def internal(string):
             res = self(string)
@@ -34,6 +36,7 @@ class Parser:
 
 
 def string(match, tag="string"):
+    @memoize
     @rename("string_{}".format(match))
     def internal(string):
         ln = len(match)
@@ -53,6 +56,7 @@ def regex(match, tag="regex", reopts=None):
         reopts = []
     rx = re.compile(match, *reopts)
 
+    @memoize
     @rename("regex_{}".format(match))
     def internal(string):
         res = rx.match(string)
@@ -64,6 +68,7 @@ def regex(match, tag="regex", reopts=None):
 
 
 def digit(tag="digit"):
+    @memoize
     @rename("digit")
     def internal(string):
         if not string:
@@ -77,6 +82,7 @@ def digit(tag="digit"):
 
 
 def many(parser, tag="many"):
+    @memoize
     @rename("many_{}".format(parser.name))
     def internal(string):
         res = parser(string)
@@ -94,6 +100,7 @@ def many(parser, tag="many"):
 
 
 def many1(parser, tag="many1"):
+    @memoize
     @rename("many1_{}".format(parser.name))
     def internal(string):
         res = parser(string)
@@ -111,6 +118,7 @@ def many1(parser, tag="many1"):
 
 
 def whitespace(tag="whitespace"):
+    @memoize
     @rename("whitespace")
     def internal(string):
         if not string:
@@ -124,6 +132,7 @@ def whitespace(tag="whitespace"):
 
 
 def skip(parser, tag="skip"):
+    @memoize
     @rename("skip_{}".format(parser.name))
     def internal(string):
         res = parser(string)
@@ -139,6 +148,7 @@ def skipmany(parser, tag="skipmany"):
 
 
 def sep_by(separator, parser, tag="sep_by"):
+    @memoize
     @rename("{}_sep_by_{}".format(parser.name, separator.name))
     def internal(string):
         if not string:
@@ -162,6 +172,7 @@ def sep_by(separator, parser, tag="sep_by"):
 
 
 def opt(parser, tag="opt"):
+    @memoize
     @rename("opt_{}".format(parser.name))
     def internal(string):
         res = parser(string)
@@ -172,6 +183,7 @@ def opt(parser, tag="opt"):
 
 
 def seq(*parsers, tag="seq"):
+    @memoize
     @rename("seq_{}".format("_".join(str(parser.name) for parser in parsers)))
     def internal(string):
         resl = []
@@ -187,6 +199,7 @@ def seq(*parsers, tag="seq"):
 
 
 def all(parser, tag="all"):
+    @memoize
     @rename("all_{}".format(parser.name))
     def internal(string):
         res = parser(string)
diff --git a/gll/util.py b/gll/util.py
index 7e3413d..063c991 100644
--- a/gll/util.py
+++ b/gll/util.py
@@ -1,5 +1,17 @@
+from functools import wraps
+
 def rename(name):
     def wrapped(f):
         f.__name__ = name
         return f
     return wrapped
+
+
+def memoize(f):
+    d = {}
+    @wraps(f)
+    def internal(arg):
+        if arg not in d:
+            d[arg] = f(arg)
+        return d[arg]
+    return internal