R help - Mar 2008 - source() behavior I don't understand

temp.ttt <- "ttt <- 1\nttt"
conn.ttt <- textConnection(temp.ttt)
source(conn.ttt, echo=TRUE)  ## name of variable is echoed
close(conn.ttt)
cat(file="c:/temp/temp.R", temp.ttt)  ## name of variable not echoed
source("c:/temp/temp.R", echo=TRUE)


temp.abc <- "abc <- 1\nabc"
conn.abc <- textConnection(temp.abc)
source(conn.abc, echo=TRUE)  ## name of variable is echoed
close(conn.abc)
cat(file="c:/temp/temp.R", temp.abc)  ## name of variable is echoed
source("c:/temp/temp.R", echo=TRUE)


The behavior I don't understand is why the variable name "ttt" is
not echoed
when sourced from a file.  It is echoed when sourced from a character string.
The name is echoed in both situations when it begins with a letter other
than "t".  Specifically I have tested "tt" and
"ttt".

I am using R-2.6.1 on Windows.

Rich

Put 'print' around your variable:
> temp.ttt <- "ttt <- 1\nprint(ttt)"
> conn.ttt <- textConnection(temp.ttt)
> source(conn.ttt, echo=TRUE)  ## name of variable is echoed
> ttt <- 1
> print(ttt)
[1] 1
> close(conn.ttt)
> cat(file="c:/temp/temp.R", temp.ttt)  ## name of variable not
echoed
> source("c:/temp/temp.R", echo=TRUE)
> ttt <- 1
> print(ttt)
[1] 1
>
>
> temp.abc <- "abc <- 1\nprint(abc)"
> conn.abc <- textConnection(temp.abc)
> source(conn.abc, echo=TRUE)  ## name of variable is echoed
> abc <- 1
> print(abc)
[1] 1
> close(conn.abc)
> cat(file="c:/temp/temp.R", temp.abc)  ## name of variable is
echoed
> source("c:/temp/temp.R", echo=TRUE)
> abc <- 1
> print(abc)
[1] 1
>

On Sun, Mar 9, 2008 at 9:01 PM, Richard M. Heiberger <rmh at temple.edu>
wrote:
> temp.ttt <- "ttt <- 1\nttt"
> conn.ttt <- textConnection(temp.ttt)
> source(conn.ttt, echo=TRUE)  ## name of variable is echoed
> close(conn.ttt)
> cat(file="c:/temp/temp.R", temp.ttt)  ## name of variable not
echoed
> source("c:/temp/temp.R", echo=TRUE)
>
>
> temp.abc <- "abc <- 1\nabc"
> conn.abc <- textConnection(temp.abc)
> source(conn.abc, echo=TRUE)  ## name of variable is echoed
> close(conn.abc)
> cat(file="c:/temp/temp.R", temp.abc)  ## name of variable is
echoed
> source("c:/temp/temp.R", echo=TRUE)
>
>
> The behavior I don't understand is why the variable name
"ttt" is not echoed
> when sourced from a file.  It is echoed when sourced from a character
string.
> The name is echoed in both situations when it begins with a letter other
> than "t".  Specifically I have tested "tt" and
"ttt".
>
> I am using R-2.6.1 on Windows.
>
> Rich
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

On 09/03/2008 10:01 PM, Richard M. Heiberger wrote:
> temp.ttt <- "ttt <- 1\nttt"
> conn.ttt <- textConnection(temp.ttt)
> source(conn.ttt, echo=TRUE)  ## name of variable is echoed
> close(conn.ttt)
> cat(file="c:/temp/temp.R", temp.ttt)  ## name of variable not
echoed
> source("c:/temp/temp.R", echo=TRUE)
> 
> 
> temp.abc <- "abc <- 1\nabc"
> conn.abc <- textConnection(temp.abc)
> source(conn.abc, echo=TRUE)  ## name of variable is echoed
> close(conn.abc)
> cat(file="c:/temp/temp.R", temp.abc)  ## name of variable is
echoed
> source("c:/temp/temp.R", echo=TRUE)
> 
> 
> The behavior I don't understand is why the variable name
"ttt" is not echoed
> when sourced from a file.  It is echoed when sourced from a character
string.
> The name is echoed in both situations when it begins with a letter other
> than "t".  Specifically I have tested "tt" and
"ttt".
Looks like a bug in a regular expression.  R doesn't echo lines 
containing nothing but blanks and tabs, and I think the regular 
expression that is supposed to match tabs is matching t instead.  Thanks 
for the report, I'll fix it.

Duncan Murdoch