macros (was: Seeking computer-programming job (Sunnyvale, CA))

From:
ram@zedat.fu-berlin.de (Stefan Ram)
Newsgroups:
comp.lang.lisp,comp.lang.java.programmer
Date:
15 May 2009 13:47:00 GMT
Message-ID:
<macros-20090515154104@ram.dialup.fu-berlin.de>
pjb@informatimago.com (Pascal J. Bourguignon) writes:

Well at that point I can only say that, well over here we're not (all)
raving maniacs, that we have useful tools that help solve or obviate a
lot of problems found with other programming languages, and point to
that tutorial: http://www.lisperati.com/casting.html


  Assume for a moment I had advanced macro capabilities in Java.
  I'd write:

public static String getMultiValue( Object valueObject )
{ String result = null;
  if( valueObject == null )result = null;

  else if( StringValue stringValue =? valueObject )
  result = getStringValue( stringValue );

  else if( SprayValue sprayValue =? valueObject )
  result = getSetValue( setValue );

  return result; }

  The macro here is marked by the occurence of ?=??, which is
  not a regular Java operator, but part of my hypothetical macro
  call pattern.

  The problem here is readability:

  Can others know, what ?=?? means in my macro package?
  Can they know how to immediately find its documentation?

  If I invent and use this macro now, will even I myself
  remember its meaning a year later?

  The same coded in Java without macros /is/ more verbose,
  but also more readable to someone who knows Java:

public static String getMultiValue( Object valueObject )
{ String result = null;
  if( valueObject == null )result = null;

  else if( valueObject instanceof StringValue )
  { StringValue stringValue =( StringValue )valueObject;
    result = getStringValue( stringValue ); }

  else if( valueObject instanceof SprayValue )
  { SprayValue setValue =( SprayValue )valueObject;
    result = getSetValue( setValue ); }

  return result; }

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