Re: [Rd] parse( connection) and source-keeping

From: Duncan Murdoch <>
Date: Wed, 11 Jan 2012 20:36:03 -0500

On 12-01-11 3:54 PM, wrote:
> In R<= 2.13.x, calling 'parse( con)' where 'con' is a connection, 'options( keep.source)' is TRUE, and default 'srcfile' would preserve the source. In R>= 2.14.1, it doesn't.

Actually, it preserved the "source" attribute of the function if it could, but didn't add a srcref. Sometimes it would fail, giving a message like

Error in parse(textConnection(texto)) :

   function is too long to keep source (at line 8812)

>> tf<- tempfile()
>> options( keep.source=TRUE)
>> texto<- c( 'function() { # comment', '}')
>> parse( text=texto)
> expression(function() { # comment
> })
>> cat( texto, file=tf, sep='\n')
>> parse( file=tf)
> expression(function() { # comment
> })
>> parse( file( tf))
> expression(function() {
> })
>> parse( textConnection( texto))
> expression(function() {
> })
> and yes I didn't bother closing any connections.
> My suspicion is that this change is unintentional, and it seems to me that the best option would be for 'connection' to work like 'text' does here, ie to attach a 'srcfilecopy' containing the contents.

Yes, that does sound like a good idea.

Duncan Murdoch

> I didn't submit a bug report because the documentation (which hasn't changed in this respect) actually doesn't say what 'parse' should do with 'connection' (as opposed to 'text' or 'file') argument when 'getOption( keep.source)' is TRUE and 'srcfile' is NULL. [BTW it's also unstated which argument takes precedence if a non-default 'srcfile' argument is specified.] So some additional explanation is needed there at a minimum, but also a decision as to what the best behaviour would be.
> bye
> Mark
> Mark Bravington
> Marine Lab
> Hobart
> Australia
> ______________________________________________
> mailing list
> mailing list Received on Thu 12 Jan 2012 - 01:48:36 GMT

This quarter's messages: by month, or sorted: [ by date ] [ by thread ] [ by subject ] [ by author ]

All messages

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Thu 12 Jan 2012 - 16:10:08 GMT.

Mailing list information is available at Please read the posting guide before posting to the list.

list of date sections of archive