Hello,
Would it be possible to have a custom prompt when browser()'ing.
I have made a simple implementation of this (which is attached), the
basic idea is that instead of the hardcoded sprintf( "Browser[%d]> ",
browselevel), a call to the getBrowsePrompt is made, and obviously the
function is:
> getBrowsePrompt
function (level = 1, env = .GlobalEnv) {
sprintf("Browse[%d]> ", level)
}
<environment: namespace:base>
> debug( rnorm )
> rnorm( 10 )
debugging in: rnorm(10)
debug: .Internal(rnorm(n, mean, sd))
Browse[1]>
exiting from: rnorm(10)
[1] -0.496598526 -0.006482431 1.491833990 -2.602605734 -0.275479145
[6] -1.143580117 0.146797854 -0.529420397 0.823817647 -0.256676050
but then it can be masked so that a more informative prompt is given,
like this for example (showing the call stack)
> getBrowsePrompt
function( level = 1, env = .GlobalEnv){
calls <- sys.calls()
stack <- sapply( calls[-1], function(x) tryCatch(as.character(x[[1]]),
error=function(e) "?") )
sprintf( "Browse[%d] %s > ", level, paste( stack, collapse = " -> ") )
}
> f()
debugging in: rnorm(10)
debug: .Internal(rnorm(n, mean, sd))
Browse[1] rnorm -> getBrowsePrompt >
exiting from: rnorm(10)
[1] -0.53854862 -1.42674850 -0.48391168 -0.23446819 -0.36863380 0.53803626
[7] 1.70176078 0.82984068 1.05101379 -0.03944557
Or this: printing the content of the environment we are browsing :
> getBrowsePrompt <- function( level = 1, env = .GlobalEnv ){
+ print( ls.str( envir = env) )
+ base:::getBrowsePrompt( level, env )
+ }
> f()
debugging in: rnorm(10)
debug: .Internal(rnorm(n, mean, sd))
mean : num 0
n : num 10
sd : num 1
Browse[1]>
exiting from: rnorm(10)
[1] 1.1112007 0.4921306 0.1747196 -0.2518565 -0.9342039 0.5930085
[7] -0.5961234 0.1153541 -0.6189056 0.1670318
This probably should rely on an option instead of relying on masking
functions. Also this opens a back door to the debugging system of R, but
I am not sure this is entirely a bad thing. (see
http://www.statistik.lmu.de/~eugster/soc09/#p5)
On the same note, what about having a function for the prompt, so that
(for example) we could show the current working directory, the memory
usage, ...
Romain
--
Romain Francois
Independent R Consultant
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
Index: src/library/base/R/options.R
===================================================================
--- src/library/base/R/options.R (revision 48377)
+++ src/library/base/R/options.R (working copy)
@@ -18,3 +18,7 @@
getOption <- function(x) options(x)[[1L]]
+getBrowsePrompt <- function( level = 1, env = .GlobalEnv){
+ sprintf( "Browse[%d]> ", level )
+}
+
Index: src/main/main.c
===================================================================
--- src/main/main.c (revision 48377)
+++ src/main/main.c (working copy)
@@ -116,20 +116,26 @@
/* Read-Eval-Print loop with interactive input */
static int prompt_type;
-static char BrowsePrompt[20];
-
-char *R_PromptString(int browselevel, int type)
+char *R_PromptString(int browselevel, int type, SEXP rho)
{
if (R_Slave) {
- BrowsePrompt[0] = '\0';
- return BrowsePrompt;
+ return "" ;
}
else {
if(type == 1) {
if(browselevel) {
- sprintf(BrowsePrompt, "Browse[%d]> ", browselevel);
- return BrowsePrompt;
+ SEXP call ;
+ SEXP level ;
+ SEXP res ;
+ char* prompt ;
+ PROTECT( level = allocVector(INTSXP, 1) ) ;
+ INTEGER(level)[0] = browselevel ;
+ PROTECT( call = lang3( install("getBrowsePrompt"), level, rho ) ) ;
+ PROTECT( res = eval( call, R_GlobalEnv ) );
+ prompt = (char *)CHAR(STRING_ELT(res, 0)) ;
+ UNPROTECT( 3 ) ;
+ return prompt ;
}
return (char *)CHAR(STRING_ELT(GetOption(install("prompt"),
R_BaseEnv), 0));
@@ -202,7 +208,7 @@
if(!*state->bufp) {
R_Busy(0);
- if (R_ReadConsole(R_PromptString(browselevel, state->prompt_type),
+ if (R_ReadConsole(R_PromptString(browselevel, state->prompt_type, rho),
state->buf, CONSOLE_BUFFER_SIZE, 1) == 0)
return(-1);
state->bufp = state->buf;
@@ -331,7 +337,7 @@
if(!*DLLbufp) {
R_Busy(0);
- if (R_ReadConsole(R_PromptString(0, prompt_type), DLLbuf,
+ if (R_ReadConsole(R_PromptString(0, prompt_type, R_GlobalEnv), DLLbuf,
CONSOLE_BUFFER_SIZE, 1) == 0)
return -1;
DLLbufp = DLLbuf;
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
