bugfix: proper cache for generic instantiations

lib/pure/matchers.nim

@@ -0,0 +1,51 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2011 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module contains various string matchers for email addresses, etc.
+{.deadCodeElim: on.}
+
+{.push debugger:off .} # the user does not want to trace a part
+                       # of the standard library!
+
+include "system/inclrtl"
+
+import strutils
+
+proc validEmailAddress*(s: string): bool {.noSideEffect,
+  rtl, extern: "nsuValidEmailAddress".} = 
+  ## returns true if `s` seems to be a valid e-mail address. 
+  ## The checking also uses a domain list.
+  const
+    chars = Letters + Digits + {'!','#','$','%','&',
+      '\'','*','+','/','=','?','^','_','`','{','}','|','~','-','.'}
+  var i = 0
+  if s[i] notin chars or s[i] == '.': return false
+  while s[i] in chars: 
+    if s[i] == '.' and s[i+1] == '.': return false
+    inc(i)
+  if s[i] != '@': return false
+  var j = len(s)-1
+  if s[j] notin letters: return false
+  while j >= i and s[j] in letters: dec(j)
+  inc(i) # skip '@'
+  while s[i] in {'0'..'9', 'a'..'z', '-', '.'}: inc(i) 
+  if s[i] != '\0': return false
+  
+  var x = substr(s, j+1)
+  if len(x) == 2 and x[0] in Letters and x[1] in Letters: return true
+  case toLower(x)
+  of "com", "org", "net", "gov", "mil", "biz", "info", "mobi", "name",
+     "aero", "jobs", "museum": return true
+  return false
+
+when isMainModule:
+  assert "wuseldusel@codehome.com".validEmailAddress
+  
+{.pop.}
+