(islower): New function. Use it instead of "".islower.

(isspace): New function.  Use it instead of "".isspace.

doc/checkargs.py

@@ -67,12 +67,24 @@ def isupper(s):
             return 0
     return 1
 
+def islower(s):
+    for c in s:
+        if c not in "abcdefghijklmnopqrstuvwxyz":
+            return 0
+    return 1
+
 def isdigit(s):
     for c in s:
         if c not in "0123456789":
             return 0
     return 1
 
+def isspace(s):
+    for c in s:
+        if c not in " \n":      # There should be no \t or \r in this file...
+            return 0
+    return 1
+
 class reader_eof(Exception):
     pass
 
@@ -1127,7 +1139,7 @@ class lexer:
             else:
                 if c == '-':
                     upper = 1
-                elif not c.islower():
+                elif not islower(c):
                     ok = 0
         if ok and tp[-1] == '-':
             ok = 0
@@ -1143,10 +1155,10 @@ class lexer:
         ok = 1
         if len(arg) < 0:
             ok = 0
-        if ok and not arg[0].islower():
+        if ok and not islower(arg[0]):
             ok = 0
         for c in arg[1:]:
-            if not c.islower() and c != '-':
+            if not islower(c) and c != '-':
                 ok = 0
         if ok and arg[-1] == '-':
             ok = 0
@@ -1191,7 +1203,7 @@ class lexer:
             del self.__tokens[0]
             return res
         c = self.__reader.getc()
-        while c.isspace():
+        while isspace(c):
             c = self.__reader.getc()
         if isalpha(c):
             res = c