[Rd] A couple of suggestions: source function (package base)

[Jose Claudio Faria]

Hi,

I've been calling the function "source" (package base) from Tinn-R editor to
send files, marked blocks and selections to R interpreter because it avoids a
lot of problems related with input/output synchronization in the Rgui output!

The new RGedit plugin is also using this function in this way, and we are
finishing a new version of a plugin to Vim (Vim-R-plugin2) which uses
also source().

So, I would like to propose two small changes in this function:

1. The "max.deparse" parameter could be a global option with 150 as
the default value.

   Why? It will avoid the need to send this parameter repeatedly,
which causes visual pollution in the console.

2. A new parameter (for example: "new.line") to allow the user to
define whether a new blank line between the output and the subsequent
input is desired when "echo=T".

Example, suppose I have in the editor the three lines below:

a=rnorm(10)
a
sort(a)

and I would like to send it to R interpreter (file, block or selection).

The current output is (using Vim-R-plugin2):
-------------------------------------------
> source('/tmp/.Rsource-jcfaria', echo=TRUE, max.deparse=50)

> a=rnorm(10)

> a
 [1]  0.08648104 -1.74996635  0.61027538  0.42042031 -0.02025884 -0.39891256
 [7] -0.30219635 -0.84476668  1.06341674 -0.12030620

> sort(a)
 [1] -1.74996635 -0.84476668 -0.39891256 -0.30219635 -0.12030620 -0.02025884
 [7]  0.08648104  0.42042031  0.61027538  1.06341674

>


How it could be (desired):
-------------------------
> source('/tmp/.Rsource-jcfaria', echo=TRUE)
> a=rnorm(10)
> a
 [1]  0.08648104 -1.74996635  0.61027538  0.42042031 -0.02025884 -0.39891256
 [7] -0.30219635 -0.84476668  1.06341674 -0.12030620
> sort(a)
 [1] -1.74996635 -0.84476668 -0.39891256 -0.30219635 -0.12030620 -0.02025884
 [7]  0.08648104  0.42042031  0.61027538  1.06341674
>

I think that both "new.line" and "max.deparse" could be both global options.

max.deparse = 150 (default)
new.line    = FALSE (default)

Why? To get a clearer output.

In this way the args of this function would become:
---------------------------------------------------
function (file, local = FALSE, echo = verbose, print.eval = echo,
    verbose = getOption("verbose"), prompt.echo = getOption("prompt"),
->  max.deparse.length = getOption("max.deparse"), new.line =
getOption("new.line"), <-
    chdir = FALSE, encoding = getOption("encoding"), continue.echo =
getOption("continue"),
    skip.echo = 0, keep.source = getOption("keep.source"))

For GUI/Editor developers this changes will allow to send simpler
instructions and
make nice and standard interfaces.

Is it possible to create the "new.line" argument and to put it and
"max.deparse" between the global options?

I would prefer not creating a custom version of source() because I
think that these changes would be of
benefit to other people and projects.

Thanks,
-- 
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Jose Claudio Faria
Estatistica - prof. Titular
UESC/DCET/Brasil
joseclaudio.faria at gmail.com
joseclaudio.faria at terra.com.br
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