R help - Nov 2009 - deparse() and the 'else' statement

Hi all,

It is recommended in ?'if' that we use 'else' right after
'}' instead
of starting a new line, but I noticed deparse() will separate '}' and
'else' when the 'if...else' clause is used inside {...} (e.g.
function
body). Here is an example:

## if/else inside {}
> cat(deparse(parse(text='function(){if (TRUE) {1} else {2}}')),
sep='\n')
structure(expression(function() {
    if (TRUE) {
        1
    }
    else {
        2
    }
}), srcfile = <environment>)
## no {}
> cat(deparse(parse(text='if (TRUE) {1} else {2}')),
sep='\n')
structure(expression(if (TRUE) {
    1
} else {
    2
}), srcfile = <environment>)

I wonder if there is a way to let 'else' stay with '}' when
deparsing
the expression. Thanks!
> sessionInfo()
R version 2.10.0 (2009-10-26)
i386-pc-mingw32

locale:
[1] LC_COLLATE=Chinese_People's Republic of China.936
[2] LC_CTYPE=Chinese_People's Republic of China.936
[3] LC_MONETARY=Chinese_People's Republic of China.936
[4] LC_NUMERIC=C
[5] LC_TIME=Chinese_People's Republic of China.936

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] animation_1.0-8 MASS_7.3-3

loaded via a namespace (and not attached):
[1] tools_2.10.0

Regards,
Yihui
--
Yihui Xie <xieyihui at gmail.com>
Phone: 515-294-6609 Web: http://yihui.name
Department of Statistics, Iowa State University
3211 Snedecor Hall, Ames, IA

On 09/11/2009 4:20 PM, Yihui Xie wrote:
> Hi all,
> 
> It is recommended in ?'if' that we use 'else' right after
'}' instead
> of starting a new line, but I noticed deparse() will separate '}'
and
> 'else' when the 'if...else' clause is used inside {...}
(e.g. function
> body). Here is an example:
> 
> ## if/else inside {}
>> cat(deparse(parse(text='function(){if (TRUE) {1} else {2}}')),
sep='\n')
> structure(expression(function() {
>     if (TRUE) {
>         1
>     }
>     else {
>         2
>     }
> }), srcfile = <environment>)
> ## no {}
>> cat(deparse(parse(text='if (TRUE) {1} else {2}')),
sep='\n')
> structure(expression(if (TRUE) {
>     1
> } else {
>     2
> }), srcfile = <environment>)
> 
> I wonder if there is a way to let 'else' stay with '}' when
deparsing
> the expression. Thanks!
No, there isn't.  You're welcome to submit a well-tested patch, but 
please accompany it with a stronger argument in its favour.  Just 
because humans are advised to type their code one way doesn't mean R 
should, as long as it parses correctly.

Duncan Murdoch
> 
>> sessionInfo()
> R version 2.10.0 (2009-10-26)
> i386-pc-mingw32
> 
> locale:
> [1] LC_COLLATE=Chinese_People's Republic of China.936
> [2] LC_CTYPE=Chinese_People's Republic of China.936
> [3] LC_MONETARY=Chinese_People's Republic of China.936
> [4] LC_NUMERIC=C
> [5] LC_TIME=Chinese_People's Republic of China.936
> 
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
> 
> other attached packages:
> [1] animation_1.0-8 MASS_7.3-3
> 
> loaded via a namespace (and not attached):
> [1] tools_2.10.0
> 
> Regards,
> Yihui
> --
> Yihui Xie <xieyihui at gmail.com>
> Phone: 515-294-6609 Web: http://yihui.name
> Department of Statistics, Iowa State University
> 3211 Snedecor Hall, Ames, IA
> 
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