R help - Apr 2009 - new line between '}' and 'else' in function body

Hi list members,

?"else" tells us

     In particular, you should not have a newline between '}' and
     'else' to avoid a syntax error in entering a 'if ... else'
     construct at the keyboard or via 'source'.

but there's no syntax error when you break the line between "}"
and
"else" in a function, e.g.

f = function(x) {
    if (x) {
        1
    } # a new line here!
    else {
        2
    }
}
> f(TRUE)
[1] 1
> f(FALSE)
[1] 2

Seems strange...

Regards,
Yihui
--
Yihui Xie <xieyihui at gmail.com>
Phone: +86-(0)10-82509086 Fax: +86-(0)10-82509086
Mobile: +86-15810805877
Homepage: http://www.yihui.name
School of Statistics, Room 1037, Mingde Main Building,
Renmin University of China, Beijing, 100872, China

Hi,

That's because the parser knows how to deal with that stuff. However, 
when you type the same if/else at the command line, it will be parsed 
line by line, and the evaluator will not wait for the else to evaluate 
the if. Try to copy and paste your if/else to the command line.

Romain


Yihui Xie wrote:
> Hi list members,
>
> ?"else" tells us
>
>      In particular, you should not have a newline between '}' and
>      'else' to avoid a syntax error in entering a 'if ...
else'
>      construct at the keyboard or via 'source'.
>
> but there's no syntax error when you break the line between
"}" and
> "else" in a function, e.g.
>
> f = function(x) {
>     if (x) {
>         1
>     } # a new line here!
>     else {
>         2
>     }
> }
>
>   
>> f(TRUE)
>>     
> [1] 1
>   
>> f(FALSE)
>>     
> [1] 2
>
> Seems strange...
>
> Regards,
> Yihui
> --
> Yihui Xie <xieyihui at gmail.com>
> Phone: +86-(0)10-82509086 Fax: +86-(0)10-82509086
> Mobile: +86-15810805877
> Homepage: http://www.yihui.name
> School of Statistics, Room 1037, Mingde Main Building,
> Renmin University of China, Beijing, 100872, China
>   

-- 
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr