From fabb4c15215546fd36a461c8956dc310a4f35ac0 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sun, 25 Feb 2024 17:42:06 -0800
Subject: Use global array for FIFO.

The $c1 to $c9 variables are now just derived items.

* cdlog.sh (cdlog_fifo): New array variable.
(cdlog.args): Now all this function does is copy
from the array to the short variables.
(cdlog.update): Now calls cdlog.args to copy
${cdlog_fifo[@]} to $c1 to $c9.
(cdlog.init): Initialize dclog_fifo via ${d[]}
alias, and call cdlog.args to also init the short
variables.
(cdlog.recover): Map from file directly into
cdlog_fifo array, and call cdlog.update instead
of cdlog.args.
(cdlog.chdir, cdlog.rot, cdlog.pop): Local array d is alias
for cdlog_fifo.  Use cdlog.update instead of cdlog.args.
(cdlog.mcd): Local array d is alias for cdlog_fifo.

* README.md: Don't say that the FIFO is stored in variables
c1 through c9 but in in the cdlog_fifo array. The variables
are now for convenience only.
---
 README.md |  8 +++----
 cdlog.sh  | 79 +++++++++++++++++++++++++++++++--------------------------------
 2 files changed, 43 insertions(+), 44 deletions(-)

diff --git a/README.md b/README.md
index 2a248f1..99a1fd8 100644
--- a/README.md
+++ b/README.md
@@ -14,10 +14,10 @@ The user interface consists of three commands:
 
 * `cd` is now an alias which calls the function `cdlog.chdir`.
 Every time you change directory, it pushes the previous directory
-into a FIFO log. The log maintains nine entries. The ninth entry
-is erased. The entries are stored in the variables `c1` through `c9`.
-The first four entries are also copied into the variables `x`, `y`,
-`z` and `w` for shorter access.
+into a FIFO log which is stored in the `cdlog_fifo` array. The log maintains
+nine entries. The ninth entry is erased. The entries are copied into
+the variables `c1` through `c9`.  The first four entries are also
+copied into the variables `x`, `y`, `z` and `w` for shorter access.
 
 * `cs` (cd swap) is an alias for a command which exchanges
 the current directory with a selected `cslog` entry selected
diff --git a/cdlog.sh b/cdlog.sh
index fd1b220..4c9fb91 100644
--- a/cdlog.sh
+++ b/cdlog.sh
@@ -1,19 +1,31 @@
 # License at bottom.
 
 # Globals
+declare -a cdlog_fifo             # directory FIFO
 declare -A cdlog_alias            # cd aliases
 
+unset cdlog_alias[0]              # FIFO is 1-based
+
 # Configuration variables
 cdlog_lru=${cdlog_lru-}
 
-# Update after FIFO change.
-cdlog.update()
+# Set state from args
+cdlog.args()
 {
-  # Update the one-letter nicknames for most recent four dirs.
+  c1=$1; c2=$2; c3=$3
+  c4=$4; c5=$5; c6=$6
+  c7=$7; c8=$8; c9=$9
+
   x=$c1
   y=$c2
   z=$c3
   w=$c4
+}
+
+# Update after FIFO change.
+cdlog.update()
+{
+  cdlog.args "${cdlog_fifo[@]}"
 
   # Persist to disk.
   cat > "$cdlog_dirs" <<!
@@ -30,16 +42,6 @@ $c9
 !
 }
 
-# Set state from args
-cdlog.args()
-{
-  c1=$1; c2=$2; c3=$3
-  c4=$4; c5=$5; c6=$6
-  c7=$7; c8=$8; c9=$9
-
-  cdlog.update
-}
-
 # Utility for nth positional param
 cdlog.get_param()
 {
@@ -55,10 +57,11 @@ cdlog.init()
   local i
   local oldest
   local context
+  declare -n d=cdlog_fifo
 
-  c9=; c8=; c7=
-  c6=; c5=; c4=
-  c3=; c2=
+  d[9]=; d[8]=; d[7]=;
+  d[6]=; d[5]=; d[4]=;
+  d[3]=; d[2]=
 
   cdlog_dirs=
   context=
@@ -87,11 +90,13 @@ cdlog.init()
   if [ $# -gt 0 -a $1 != ~/.cdlog.'*'.dirs ] ; then
     printf "Use 'cdr' or 'cdlog.recover' to switch to prior cdlog context.\n"
   fi
+
+  # Also init var nicknames, but don't save context
+  cdlog.args "${d[@]}"
 }
 
 cdlog.recover()
 {
-  local -a d
   local dir
   local i
   local sel
@@ -137,10 +142,10 @@ cdlog.recover()
   fi
 
   if [ -f "$cdlog_dirs" ] ; then
-    mapfile -t d < "$cdlog_dirs"
-    command cd "${d[0]}"
-    unset d[0]
-    cdlog.args "${d[@]}"
+    mapfile -t cdlog_fifo < "$cdlog_dirs"
+    command cd "${cdlog_fifo[0]}"
+    unset cdlog_fifo[0]
+    cdlog.update
   fi
 }
 
@@ -167,12 +172,12 @@ cdlog.chdir()
     # only if we successfully change to a different
     # directory do the following
 
+    declare -n d=cdlog_fifo
+
     if [ $cdlog_lru ] ; then
       local nx=
       local pv=$cur
       local i
-      local d=("" "$c1" "$c2" "$c3" "$c4" "$c5" "$c6" "$c7" "$c8" "$c9")
-      unset d[0]
 
       for ((i = 1; i <= 9; i++)); do
         nx=${d[$i]}
@@ -182,17 +187,15 @@ cdlog.chdir()
         fi
         pv=$nx
       done
-
-      cdlog.args "${d[@]}"
     else
-      c9=$c8; c8=$c7; c7=$c6
-      c6=$c5; c5=$c4; c4=$c3
-      c3=$c2; c2=$c1
-
-      c1=$cur
+      for ((i = 8; i >= 2; i--)); do
+        d[$((i+1))]=d[$i]
+      done
 
-      cdlog.update
+      d[1]=$cur
     fi
+
+    cdlog.update
   fi
 }
 
@@ -202,11 +205,9 @@ cdlog.rot()
   local cur=$PWD
   local p=$cur
   local n=$cur
-  local d=("" "$c1" "$c2" "$c3" "$c4" "$c5" "$c6" "$c7" "$c8" "$c9")
+  declare -n d=cdlog_fifo
   local first=y
 
-  unset d[0]
-
   [ $# -gt 0 ] || set 1
 
   while [ $# -gt 0 ] ; do
@@ -231,7 +232,7 @@ cdlog.rot()
 
   d[$p]=$cur
 
-  cdlog.args "${d[@]}"
+  cdlog.update
 }
 
 
@@ -239,12 +240,10 @@ cdlog.rot()
 # from the log.
 cdlog.pop()
 {
-  local d=("" "$c1" "$c2" "$c3" "$c4" "$c5" "$c6" "$c7" "$c8" "$c9")
+  declare -n d=cdlog_fifo
   local n=1
   local i
 
-  unset d[0]
-
   if [ $# -gt 0 ] ; then
     n=$1; shift
   fi
@@ -256,7 +255,7 @@ cdlog.pop()
         d[$i]=${d[$((i + 1))]}
       done
       d[9]=
-      cdlog.args "${d[@]}"
+      cdlog.update
       printf "%s\n" "$PWD"
     fi
     ;;
@@ -291,7 +290,7 @@ cdlog.mcd()
   local swap=
   local res=1
   local i
-  local d=("" "$c1" "$c2" "$c3" "$c4" "$c5" "$c6" "$c7" "$c8" "$c9")
+  declare -n d=cdlog_fifo
 
   if [ $# -gt 0 ] && [ "$1" = -s ] ; then
     swap=y
-- 
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