C++ code generation from xml

[phil hunt]

On Mon, 15 Apr 2002 11:03:04 +0300, Max Ischenko <max at malva.com.uaREMOVE.IT> wrote:
>
>Hi there.
>
>I have a Python program that uses data stored in XML file to generate some
>C++ code. The problem (or, more precisely, code smell) I have is that the
>actual generation algorithm is hardwired into python and therefore is
>cryptic, difficult to understand and maintain.
>
>Small example:
>	def genBody(self, c):
>		name = c.cxxClassName
>		new = 'new %s(%s);' % (name, c.factoryCtorArg or '')
>		if c.factoryNargs == 0:
>			return '\treturn %s' % new
>		body = '\t%s * c = %s\n' % (name, new)
>		body = body + '\tc->setCmdArgs(args);\n'
>		return '%s\treturn c;' % body

How about:

template1 = """\
   return new $name($ctorArg);
"""

template2 = """\
   $name * c = new $name($ctorArg);
   c->setCmdArgs(args);
   return c;
"""
   
   def genBody(self, c):
      substitutions = { 
         "name": c.cxxClassName,
         "ctorArg": c.factoryCtorArg or ''}
      if c.factoryNargs == 0:
         return subst(template1, substitutions)
      else 
         return subst(template2, substitutions)


   def subst(formatString, args):
      f = ... in formatString convert all $xxx to %(xxx)s ...
      return f % args

The implementation of subst() is left as an exercise.


-- 
<"><"><"> Philip Hunt <philh at comuno.freeserve.co.uk> <"><"><">
"I would guess that he really believes whatever is politically 
advantageous for him to believe." 
                        -- Alison Brooks, referring to Michael
                              Portillo, on soc.history.what-if