From plummer@iarc.fr  Mon Mar 29 18:25:25 1999
From: plummer@iarc.fr (plummer@iarc.fr)
Date: Mon, 29 Mar 1999 19:25:25 +0200
Subject: readline() (PR#147)
Message-ID: <199903291725.TAA29587@blueberry.kubism.ku.dk>

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Peter Dalgaard BSA <p.dalgaard@biostat.ku.dk> writes:
>Great... Now do you have a fix for the fix? ;^)

Here are two patches.
1. Patch to scan.c which fixes this bug, and similar ones,
   by ensuring that functions which set the console prompt
   reset it after use.
2. Implements Peter Holzer's suggestion, adding a
   "prompt" argument to readline.  Since readline is an
   "internal" function I did this in the C code. The
   alternative of adding some interpreted code would be
   simpler.  Caveat emptor with this one, obviously.

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--- scan.c	Sun Mar 28 10:03:05 1999
+++ scan.c.fixed	Sun Mar 28 10:32:44 1999
@@ -276,6 +276,7 @@
 	}
     }
     if (!quiet) REprintf("Read %d items\n", n);
+    if (ttyflag) ConsolePrompt[0] = '\0';
 
     if (n == 0) {
 	UNPROTECT(1);
@@ -407,6 +408,7 @@
 	n++;
     }
     if (!quiet) REprintf("Read %d lines\n", n);
+    if (ttyflag) ConsolePrompt[0] = '\0';
 
     for (i = 0; i < nc; i++) {
 	old = VECTOR(ans)[i];
@@ -775,6 +777,8 @@
 	*bufp++ = c;
     }
     *bufp++ = '\0';
+    ConsolePrompt[0] = '\0';
+
     bufp = buffer;
     while (isspace(*bufp)) bufp++;
     first = LENGTH(CAR(args)) + 1;

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diff -uNr R-0.63.3/src/library/base/R/New-Internal.R R-0.63.3-patched/src/librar
y/base/R/New-Internal.R
--- R-0.63.3/src/library/base/R/New-Internal.R	Wed Dec  9 07:52:28 1998
+++ R-0.63.3-patched/src/library/base/R/New-Internal.R	Sun Mar 28 13:47:39 1999
@@ -89,7 +89,7 @@
 	stop("rank(.., na.last != TRUE) does not yet work in R.")
     .Internal(rank(x))
 }
-readline <- function().Internal(readline())
+readline <- function(prompt="").Internal(readline(prompt))
 search <- function().Internal(search())
 
 sink <- function(file=NULL, append = FALSE)
diff -uNr R-0.63.3/src/library/base/man/readline.Rd R-0.63.3-patched/src/library
/base/man/readline.Rd
--- R-0.63.3/src/library/base/man/readline.Rd	Wed Nov 19 18:38:56 1997
+++ R-0.63.3-patched/src/library/base/man/readline.Rd	Sun Mar 28 13:41:52 1999
@@ -1,9 +1,12 @@
 \name{readline}
 \title{Read a Line from the Terminal}
 \usage{
-readline()
+readline(prompt="")
 }
 \alias{readline}
+\arguments{
+\item{prompt}{the string printed when prompting the user for input.}
+}
 \description{
   \code{readline} reads a line from the terminal, returning it as a
   character string.
diff -uNr R-0.63.3/src/main/names.c R-0.63.3-patched/src/main/names.c
--- R-0.63.3/src/main/names.c	Sun Jan 31 12:24:09 1999
+++ R-0.63.3-patched/src/main/names.c	Sun Mar 28 12:55:46 1999
@@ -482,7 +482,7 @@
 {"substitute",	do_substitute,	0,	0,	-1,	PP_FUNCALL},
 {"quit",	do_quit,	0,	111,	1,	PP_FUNCALL},
 {"interactive",	do_interactive,	0,	0,	0,	PP_FUNCALL},
-{"readline",	do_readln,	0,	11,	0,	PP_FUNCALL},
+{"readline",	do_readln,	0,	11,	1,	PP_FUNCALL},
 {"menu",	do_menu,	0,	11,	1,	PP_FUNCALL},
 {"print.default",do_printdefault,0,	111,	6,	PP_FUNCALL},
 {"print.matrix",do_printmatrix, 0,	111,	5,	PP_FUNCALL},
diff -uNr R-0.63.3/src/main/scan.c R-0.63.3-patched/src/main/scan.c
--- R-0.63.3/src/main/scan.c	Wed Feb 17 18:51:21 1999
+++ R-0.63.3-patched/src/main/scan.c	Sun Mar 28 15:07:24 1999
@@ -24,11 +24,12 @@
 #define SCAN_BLOCKSIZE		1000
 /* The size of the console buffer */
 #define CONSOLE_BUFFER_SIZE	1024
+#define CONSOLE_PROMPT_SIZE	32
 
 static char  ConsoleBuf[CONSOLE_BUFFER_SIZE];
 static char *ConsoleBufp;
 static int  ConsoleBufCnt;
-static char  ConsolePrompt[32];
+static char  ConsolePrompt[CONSOLE_PROMPT_SIZE];
 
 #ifdef NOT_used
 static void InitConsoleGetchar()
@@ -731,10 +732,20 @@
 {
     int c;
     char buffer[MAXELTSIZE], *bufp = buffer;
-    SEXP ans;
+    SEXP ans, prompt;
 
     checkArity(op,args);
 
+    prompt = CAR(args);
+    if (prompt == R_NilValue)
+        PROTECT(prompt);
+    else {
+        PROTECT(prompt = coerceVector(prompt, STRSXP));
+        if(length(prompt) > 0)
+            strncpy(ConsolePrompt, CHAR(*STRING(prompt)),
+                CONSOLE_PROMPT_SIZE - 1);
+    }
+
     /* skip white space */
     while ((c= ConsoleGetchar()) == ' ' || c=='\t');
     if (c != '\n' && c != R_EOF) {
@@ -749,9 +760,11 @@
     while (isspace(*--bufp))
 	;
     *++bufp = '\0';
+    ConsolePrompt[0] = '\0';
+
     PROTECT(ans = allocVector(STRSXP,1));
     STRING(ans)[0] = mkChar(buffer);
-    UNPROTECT(1);
+    UNPROTECT(2);
     return ans;
 }
 

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readline() (PR#147)
plummer@iarc.fr