<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.6000.16587" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV><FONT face="Courier New" size=2>I already tried to answer Dan Gliebold along this line, but I did not for the following caveat:</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>(define namespace (make-namespace))</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>(define (add-binding name transformer)<BR> (eval #`(define-syntax #,name #,transformer) namespace))</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>(add-binding 'name (syntax-rules () ((_) (list 'transformer))))</FONT></DIV> <DIV><FONT face="Courier New" size=2>(eval '(name) namespace) ;--> error: reference to undefined identifier: name</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>The following does work:</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>(define namespace (make-namespace))</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>(define (add-binding name transformer)<BR> (eval #`(define-syntax #,name #,transformer) namespace))</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>(add-binding #'name (syntax-rules () ((_) (list 'transformer))))</FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2>             ^^^^^^</FONT></FONT></FONT></DIV> <DIV><FONT face="Courier New" size=2>(eval '(name) namespace) ;--> (transfomer) </FONT></DIV> <DIV><FONT face="Courier New"><FONT size=2><FONT face="Courier New" size=2></FONT></FONT></FONT> </DIV> <DIV><FONT face="Courier New" size=2>Jos</FONT></DIV> <DIV><BR><FONT face="Courier New" size=2>((((lambda(x)((((((x x)x)x)x)x)x))<BR>   (lambda(x)(lambda(y)(x(x y)))))<BR>  (lambda(x)(write x)x))<BR> 'greeting)</FONT></DIV> <DIV><FONT face="Courier New" size=2>----- Original Message ----- </FONT> <DIV><FONT face="Courier New" size=2>From: "Matthew Flatt" <</FONT><A href="mailto:mflatt@cs.utah.edu"><FONT face="Courier New" size=2>mflatt@cs.utah.edu</FONT></A><FONT face="Courier New" size=2>></FONT></DIV> <DIV><FONT face="Courier New" size=2>To: "Dan Liebgold" <</FONT><A href="mailto:dan.liebgold@gmail.com"><FONT face="Courier New" size=2>dan.liebgold@gmail.com</FONT></A><FONT face="Courier New" size=2>></FONT></DIV> <DIV><FONT face="Courier New" size=2>Cc: <</FONT><A href="mailto:plt-scheme@list.cs.brown.edu"><FONT face="Courier New" size=2>plt-scheme@list.cs.brown.edu</FONT></A><FONT face="Courier New" size=2>></FONT></DIV> <DIV><FONT face="Courier New" size=2>Sent: Friday, December 14, 2007 4:41 PM</FONT></DIV> <DIV><FONT face="Courier New" size=2>Subject: Re: [plt-scheme] adding syntax transfomer to a namespace</FONT></DIV></DIV> <DIV><FONT face="Courier New"><BR><FONT size=2></FONT></FONT></DIV><FONT face="Courier New" size=2>> At Thu, 13 Dec 2007 16:25:33 -0800, "Dan Liebgold" wrote:<BR>>> Is there any way to emulate the behavior of define-syntax[es] by explicitly<BR>>> defining a transformer in a namespace?   I'd like to store a transformer in<BR>>> a list, then create a namespace later and add the transformer to it such<BR>>> that the various expand functions will honor it.<BR>> <BR>> I don't think there's any alternative to `eval' for that task:<BR>> <BR>>  (define (add-binding name transformer)<BR>>    (eval #`(define-syntax #,name #,transformer)))<BR>> <BR>> All the usual caveats for using `eval' apply in this case. (Hopefully,<BR>> those caveats will get collected in the new documentation in the near<BR>> future).<BR>> <BR>> Matthew<BR>> <BR>> _________________________________________________<BR>>  For list-related administrative tasks:<BR>>  </FONT><A href="http://list.cs.brown.edu/mailman/listinfo/plt-scheme"><FONT face="Courier New" size=2>http://list.cs.brown.edu/mailman/listinfo/plt-scheme</FONT></A><BR><FONT face="Courier New" size=2>></FONT></BODY></HTML>