[R] Continuation and parse

[Prof Brian Ripley]

On Wed, 28 Jun 2006, Jim Lemon wrote:

> Hi gurus,
>
> After an unsuccessful scrabble through the documentation and Jon's
> excellent search facility, I am no wiser as to how R recognizes an
> incomplete command line and politely raises its hand for more. The help
> page for parse gives no indication that it does anything more than spit
> the dummy when fed an incomplete command line, but something in there
> must recognize such ellipsis. Any hints?

It's internal.  Look in src/main/main.c, in particular the R_Repl* 
functions.  In short, R_Parse1Buffer can return PARSE_INCOMPLETE.

This is not done by the R-level function parse(): that parses a whole 
buffer rather than a line at a time, and maps all non-OK results to an 
error.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595