diff --git a/doc/checkargs.py b/doc/checkargs.py
new file mode 100644
index 0000000000000000000000000000000000000000..a2d701806ee8a1be1daaff8862392b0f9e0f1b1b
--- /dev/null
+++ b/doc/checkargs.py
@@ -0,0 +1,445 @@
+# Check @aarg{} and @rarg{} usage in Protocol-A.texi.
+
+import sys
+import types
+
+class reader_eof(Exception):
+    pass
+
+class reader:
+    def __init__(self, file):
+        self.__filename = file
+        self.__file = open(file, "r")
+        self.__line_no = 0
+        self.__line = []
+        self.__eof = 0
+
+    def filename(self):
+        return self.__filename
+
+    def ungetc(self, c):
+        self.__line.insert(0, c)
+
+    def getc_eofok(self):
+        if self.__line == []:
+            if self.__eof:
+                return None
+            line = self.__file.readline()
+            if line == '':
+                self.__eof = 1
+                return None
+            self.__line = list(line)
+            self.__line_no += 1
+        ret = self.__line[0]
+        del self.__line[0]
+        return ret
+
+    def getc(self):
+        c = self.getc_eofok()
+        if c == None:
+            raise reader_eof
+        return c
+
+    def line_no(self):
+        return self.__line_no
+
+class lexer:
+    def __init__(self, file):
+        self.__reader = reader(file)
+        self.__errfound = 0
+        self.__findex = None
+
+    def run(self):
+        while 1:
+            c = self.__reader.getc_eofok()
+            if c == None:
+                return self.__errfound
+            if c == '@':
+                self.__toplevel_at()
+
+    def __toplevel_at(self):
+        line_no = self.__reader.line_no()
+        c = self.__reader.getc()
+        if c in '{}@-"*':
+            return
+        cmd = ""
+        while 1:
+            if c.isalpha() or c in '_"':
+                cmd = cmd + c
+                c = self.__reader.getc()
+            elif c in ' \t\n{@=-':
+                assert cmd != ''
+                if c == '{':
+                    arg = self.__read_arg()
+                elif c == ' ' and cmd not in ['tab']:
+                    arg = self.__read_line()
+                else:
+                    arg = None
+                if c == '@':
+                    self.__reader.ungetc(c)
+
+                if hasattr(self, 'toplevel_' + cmd):
+                    getattr(self, 'toplevel_' + cmd)(arg, line_no)
+                else:
+                    self.error(line_no, "unknown command @%s{}" % cmd)
+                return
+            else:
+                self.error(line_no, "bad command ``@%s%s''" % (cmd, c))
+                return
+
+    def __read_line(self):
+        line = ""
+        while 1:
+            c = self.__reader.getc()
+            if c == '\n':
+                return line
+            line = line + c
+
+    def ignore(self, arg, line_no):
+        pass
+
+    toplevel_setfilename = ignore
+    toplevel_settitle = ignore
+    toplevel_setchapternewpage = ignore
+    toplevel_set = ignore
+    toplevel_macro = ignore
+    toplevel_code = ignore
+    toplevel_end = ignore
+    toplevel_ifinfo = ignore
+    toplevel_value = ignore
+    toplevel_copyright = ignore
+    toplevel_iftex = ignore
+    toplevel_parindent = ignore
+    toplevel_ifinfo = ignore
+    toplevel_begin = ignore
+    toplevel_titlepage = ignore
+    toplevel_title = ignore
+    toplevel_subtitle = ignore
+    toplevel_author = ignore
+    toplevel_font = ignore
+    toplevel_ignore = ignore
+    toplevel_tensltt = ignore
+    toplevel_page = ignore
+    toplevel_vskip = ignore
+    toplevel_ifnothtml = ignore
+    toplevel_contents = ignore
+    toplevel_dircategory = ignore
+    toplevel_direntry = ignore
+    toplevel_ifhtml = ignore
+    toplevel_html = ignore
+    toplevel_ifnottex = ignore
+    toplevel_top = ignore
+    toplevel_uref = ignore
+    toplevel_menu = ignore
+    toplevel_chapter = ignore
+    toplevel_uref = ignore
+    toplevel_footnote = ignore
+    toplevel_email = ignore
+    toplevel_penalty = ignore
+    toplevel_section = ignore
+    toplevel_table = ignore
+    toplevel_asis = ignore
+    toplevel_item = ignore
+    toplevel_req = ignore
+    toplevel_subsection = ignore
+    toplevel_itemize = ignore
+    toplevel_bullet = ignore
+    toplevel_multitable = ignore
+    toplevel_tab = ignore
+    toplevel_aux = ignore
+    toplevel_samp = ignore
+    toplevel_pxref = ignore
+    toplevel_errorcode = ignore
+    toplevel_misc = ignore
+    toplevel_type = ignore
+    toplevel_field = ignore
+    toplevel_dfn = ignore
+    toplevel_conftype = ignore
+    toplevel_command = ignore
+    toplevel_ref = ignore
+    toplevel_var = ignore
+    toplevel_subsubsection = ignore
+    toplevel_priv = ignore
+    toplevel_emph = ignore
+    toplevel_enumerate = ignore
+    toplevel_tindex = ignore # FIXME: check 'em?
+    toplevel_xref = ignore
+    toplevel_itemx = ignore
+    toplevel_ae = ignore
+    toplevel_i = ignore
+    toplevel_subheading = ignore
+    toplevel_c = ignore
+    toplevel_t = ignore
+    toplevel_aa = ignore
+    toplevel_async = ignore
+    toplevel_unnumbered = ignore
+    toplevel_printindex = ignore
+    toplevel_example = ignore
+
+    def toplevel_node(self, arg, line_no):
+        if self.__findex != None:
+            self.__findex = None
+            for (argname, [lineno, usage]) in self.__args.items():
+                if usage == 0:
+                    self.error(lineno,
+                               "Undocumented argument ``%s''" % (argname, ))
+            self.__findex = None
+        self.__node_name = arg
+        self.__node_start = line_no
+
+    def toplevel_findex(self, arg, line_no):
+        if self.__node_name != arg:
+            self.error(line_no, "@node/@findex mismatch: %s..." % arg)
+            self.error(line_no, "...inside node %s" % self.__node_name)
+            return
+        if self.__findex != None:
+            self.error(line_no, "multiple @findex in single @node")
+            return
+        self.__findex = arg
+        self.__args = {}
+        self.__tokens = []
+        if self.__get_token() != '@example':
+            self.error(self.__reader.line_no(), "missing @example")
+            return
+        self.__parse_request()
+
+    def toplevel_rarg(self, arg, line_no):
+        if self.__findex == None:
+            self.error(line_no, "@rarg outside @findex node")
+            return
+        if not self.__args.has_key(arg):
+            self.error(line_no, "undefined argument ``%s''" % (arg, ))
+            return
+        self.__args[arg][1] += 1
+
+    def toplevel_aarg(self, arg, line_no):
+        pass
+        # FIXME
+
+    def toplevel_bye(self, arg, line_no):
+        if self.__findex != None:
+            self.error(self.__reader.line_no(), "unterminated @findex node")
+
+    def __parse_request(self):
+        self.__tokens = []
+        req = self.__get_token()
+        if req != self.__findex:
+            self.error(self.__reader.line_no(),
+                       "wrong request name ``%s''" % req)
+            return
+
+        if self.__get_token() != '[':
+            self.error(self.__reader.line_no(), "missing ``[''")
+            return
+            
+        nr = self.__get_token()
+        if type(nr) != types.IntType:
+            self.error(self.__reader.line_no(), "bad request number")
+
+        if self.__get_token() != ']':
+            self.error(self.__reader.line_no(), "missing ``]''")
+            return
+
+        paren = self.__get_token()
+        if paren == '(':
+            next = self.__get_token()
+            if next != ')':
+                self.__unget_token(next)
+                self.__parse_request_arg()
+                next = self.__get_token()
+            if next != ')':
+                self.error(self.__reader.line_no(),
+                           "missing close parenthesis after arguments")
+                return
+        elif paren == '((':
+            self.__parse_request_arg()
+            next = self.__get_token()
+            while next == ';':
+                self.__parse_request_arg()
+                next = self.__get_token()
+            if next != '))':
+                self.error(self.__reader.line_no(),
+                           "missing double close parenthesis after arguments")
+                return
+        else:
+            self.error(self.__reader.line_no(),
+                       "missing argument list")
+            return
+
+        if self.__get_token() != '->':
+            self.error(self.__reader.line_no(), "missing ``->''")
+            return
+
+        if self.__get_token() != '(':
+            self.error(self.__reader.line_no(), "missing ``('' for result")
+            return
+
+        next = self.__get_token()
+        if next != ')':
+            self.__unget_token(next)
+            ret_type = self.__parse_type()
+            next = self.__get_token()
+        if next != ')':
+            self.error(self.__reader.line_no(), "missing ``)'' for result")
+            return
+
+        if self.__get_token() != ';':
+            self.error(self.__reader.line_no(), "missing final ``;''")
+            return
+
+        if self.__get_token() != '@end':
+            self.error(self.__reader.line_no(), "extra garbage found")
+            return
+
+        return
+
+    def __parse_type(self):
+        token = self.__get_token()
+        if token == 'ARRAY':
+            tp = self.__get_token()
+            if self.__bad_type(tp):
+                return None
+            return token + " " + tp
+        else:
+            if self.__bad_type(token):
+                return None
+            return token
+
+    def __bad_type(self, tp):
+        if tp in ['INT8', 'INT16', 'INT32']:
+            return 0
+        ok = 1
+        if len(tp) < 0:
+            ok = 0
+        if ok and not tp[0].isupper():
+            ok = 0
+        for c in tp[1:]:
+            if not c.isalpha() and c != '-':
+                ok = 0
+        if ok and tp[-1] == '-':
+            ok = 0
+        if not ok:
+            self.error(self.__reader.line_no(), "bad type name ``%s''" % (tp,))
+        return not ok
+
+    def __bad_arg(self, arg):
+        ok = 1
+        if len(arg) < 0:
+            ok = 0
+        if ok and not arg[0].islower():
+            ok = 0
+        for c in arg[1:]:
+            if not c.islower() and c != '-':
+                ok = 0
+        if ok and arg[-1] == '-':
+            ok = 0
+        if not ok:
+            if arg == '))':
+                self.error(self.__reader.line_no(),
+                           "extra semicolon after last arg")
+            else:
+                self.error(self.__reader.line_no(),
+                           "bad argument ``%s''" % (arg,))
+        return not ok
+
+    def __parse_request_arg(self):
+        argname = self.__get_token()
+        if self.__bad_arg(argname):
+            return
+        if self.__get_token() != ':':
+            self.error(self.__reader.line_no(), "missing ``:'' after argument")
+            return
+        tp = self.__parse_type()
+        if tp == None:
+            return
+        if self.__args.has_key(argname):
+            self.error(self.__reader.line_no(),
+                       "argument name ``%s'' used twice" % (argname, ))
+            return
+        self.__args[argname] = [self.__reader.line_no(), 0]
+
+    def __unget_token(self, token):
+        self.__tokens.insert(0, token)
+
+    def __get_token(self):
+        if len(self.__tokens) > 0:
+            res = self.__tokens[0]
+            del self.__tokens[0]
+            return res
+        c = self.__reader.getc()
+        while c.isspace():
+            c = self.__reader.getc()
+        if c.isalpha():
+            res = c
+            while 1:
+                c = self.__reader.getc()
+                if not c.isalpha() and c not in "-" and not c.isdigit():
+                    if c.isdigit():
+                        self.error(self.__reader.line_no(),
+                                   "bad token ``%s''" % (res + c))
+                    self.__reader.ungetc(c)
+                    return res
+                res = res + c
+        elif c in '[];:':
+            return c
+        elif c in '()':
+            d = self.__reader.getc()
+            if c != d:
+                self.__reader.ungetc(d)
+                return c
+            else:
+                return c + d
+        elif c.isdigit():
+            res = c
+            while 1:
+                c = self.__reader.getc()
+                if not c.isdigit():
+                    if c.isalpha():
+                        self.error(self.__reader.line_no(),
+                                   "bad token ``%s''" % (res + c))
+                    self.__reader.ungetc(c)
+                    if res[0] == '0' and len(res) > 1:
+                        self.error(self.__reader.line_no(),
+                                   "bad number ``%s''" % (res,))
+                    return int(res)
+                res = res + c
+        elif c == '-':
+            d = self.__reader.getc()
+            if d == '>':
+                return '->'
+            else:
+                self.error(self.__reader.line_no(),
+                           "bad token ``%s%s''" % (c, d))
+                self.__reader.ungetc(d)
+                return c
+        elif c == '@':
+            res = c
+            while 1:
+                c = self.__reader.getc()
+                if not c.isalpha():
+                    self.__reader.ungetc(c)
+                    return res
+                res = res + c
+        else:
+            self.error(self.__reader.line_no(),
+                       "bad character ``%s''" % (c,))
+            return c
+        
+                
+    def __read_arg(self):
+        arg = ""
+        while 1:
+            c = self.__reader.getc()
+            if c == '}':
+                return arg
+            else:
+                arg = arg + c
+
+    def error(self, line_no, errmsg):
+        sys.stderr.write("%s:%d:%s\n" % (self.__reader.filename(),
+                                         line_no, errmsg))
+        self.__errfound = 1
+
+if __name__ == '__main__':
+    l = lexer(sys.argv[1])
+    sys.exit(l.run())