PATCH: Tweak to read-from-minibuffer

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

The patch allows read-from-minibuffer to take two additional arguments 
which are used as the values of LBUFFER and RBUFFER.

This in turn allows one to write a widget like the following:

  self-accept () {
    zle .self-insert "$@" && inserted=1
    zle accept-line
  }

  show-matching-files () {
    local SOFAR inserted
    zle -N self-insert self-accept &&
    {
      while inserted=0; read-from-minibuffer "pattern: " "$SOFAR"
      do
        [[ -n "$REPLY" ]] && (( inserted )) || return 0
        SOFAR="$REPLY"
        zle -R "" *$~SOFAR*(N)
      done
    } always {
      zle -A .self-insert self-insert
    }
    return 1
  }

This is obviously a toy, but it shows the basic idea.  I was tempted to 
introduce LREPLY and RREPLY to get back the buffer state but decided to
let that pass pending further discussion.

Something like "self-accept" could be folded into read-from-minibuffer to 
replace the somewhat ugly -k behavior (which I've clarified in the doc, as 
it's unpleasant when N > 1).


Index: Doc/Zsh/contrib.yo
===================================================================
--- contrib.yo	3 Jul 2004 03:50:02 -0000	1.15
+++ contrib.yo	10 Jul 2004 19:24:28 -0000
@@ -742,12 +742,20 @@
 returned to the calling function in the parameter tt($REPLY) and the
 editing buffer restored to its previous state.  If the read was aborted
 by a keyboard break (typically tt(^G)), the function returns status 1
-and tt($REPLY) is not set.  If an argument is supplied to the function
-it is taken as a prompt, otherwise `tt(? )' is used.
+and tt($REPLY) is not set.
+
+If one argument is supplied to the function it is taken as a prompt,
+otherwise `tt(? )' is used.  If two arguments are supplied, they are the
+prompt and the initial value of tt($LBUFFER), and if a third argument is
+given it is the initial value of tt($RBUFFER).  This provides a default
+value and starting cursor placement.  Upon return the entire buffer is the
+value of tt($REPLY).
 
 One option is available: `tt(-k) var(num)' specifies that var(num)
 characters are to be read instead of a whole line.  The line editor is not
-invoked recursively in this case.  Note that unlike the tt(read) builtin
+invoked recursively in this case, so depending on the terminal settings
+the input may not be visible, and only the input keys are placed in
+tt($REPLY), not the entire buffer.  Note that unlike the tt(read) builtin
 var(num) must be given; there is no default.
 
 The name is a slight misnomer, as in fact the shell's own minibuffer is
Index: Functions/Zle/read-from-minibuffer
===================================================================
--- read-from-minibuffer	31 Mar 2003 18:05:19 -0000	1.2
+++ read-from-minibuffer	10 Jul 2004 19:09:31 -0000
@@ -20,8 +20,8 @@
 local savelbuffer=$LBUFFER saverbuffer=$RBUFFER
 local savepredisplay=$PREDISPLAY savepostdisplay=$POSTDISPLAY
 
-LBUFFER=
-RBUFFER=
+LBUFFER="$2"
+RBUFFER="$3"
 PREDISPLAY="$PREDISPLAY$savelbuffer$saverbuffer$POSTDISPLAY
 ${1:-? }"
 POSTDISPLAY=