Re: st: comment out a number of lines together

[Steven Samuels <sjhsamuels@earthlink.net>]

Here's another example where * works and // doesn't. The  
circumstances: the delimiter is ";", and the code block contains a - 
forvalues-  or -foreach- section.  /* and */ around the -foreach-  
section also works.

-Steve

*****************CODE BEGINS****************
sysuse auto, clear
forvalues i=1/5 {
di "rep78 = " `i'
}

#delim ;

forvalues i=1/5 { ;
di "rep78 = " `i';
};
;

***************** (*) COMMENT WORKS ****************
* forvalues i=1/5 { ;
* di "rep78 = " `i';
* };
* ;

***************** // COMMENT FAILS****************
// forvalues i=1/5 { ;
// di "rep78 = " `i';
// };
// ;
*****************CODE ENDS****************

On Oct 2, 2008, at 12:44 PM, Nick Cox wrote:


> Very good catch, Sergiy. Thanks for the correction! I should have
> checked about the //.
> Conversely, this is another argument for the deprecated *.
>
> Nick
> n.j.cox@durham.ac.uk
>
> Sergiy Radyakin
>
> Nick,
>
> local c //
> will not work in the program because "//" is interpreted as the start
> of the comment
> it works in the command line though, because "//"-style comments are
> prohibited in the command line input. To fix this:
> 1) open quotes before // like so: local c "//" , or
> 2) write it down as an expression, e.g. local c="/"+"/"
> In any case, Stata fails to recognize "//" as a comment when it comes
> as a result of macro expansion. But it works for a star ("*").
>
> // --- begin of file testc.do ---
> local c //
> display `"`c'"'
> local c ="/"+"/"
> display `"`c'"'
> local c "//"
> display `"`c'"'
> local c "*"
> display `"`c'"'
>  `c' just nothing
> local c "//"
>  `c' just nothing
> // --- end of file testc.do ---
>
> If writing out debugging messages, it may be more comfortable to use
> di_g. See: help di_g.
>
> Best regards, Sergiy Radyakin
>
> On Tue, Sep 30, 2008 at 11:28 AM, Nick Cox <n.j.cox@stata.com> wrote:
> > Another is to prefix lines by e.g.
> >
> > `c'
> >
> > Setting
> >
> > local c *
> >
> > or
> >
> > local c //
> >
> > comments out those lines.
> >
> > Setting
> >
> > local c
> >
> > zaps the macro.
> >
> > Naturally any definition of the local as "*" or "//" must precede all
> uses
> > that require that interpretation.
> >
> > The converse does not apply: if the local is not defined, Stata sees
> the
> > line.
> >
> > More generally, you can define or undefine the macro at will.
> >
> > I don't especially recommend this method, but it is an alternative
> that is
> > sometimes useful, and it matches practices in many programming
> languages.
> > Nick
> > n.j.cox@durham.ac.uk
> >
> >
> > Maarten buis wrote:
> > > --- Paul O'Brien <paul.obrien@afe2.org.uk> wrote:
> > >
> > > > at times i need to comment out a number of lines, usually with *  
> > > > and
> > > > remove the * later to activate the commands.
> > > > is there a simple way to remove and add the * to a number of  
> > > > line at
> one
> > > > go?
> > > One way to comment out a block of code is to surround them with /*
> and
> > > */ this way you have to remove only these two.
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/