Smart case sensitivity matching by default

and add parameters to force case insensitive (`-i`) or case sensitive
(`-s`) matching.

Also rename `t` variable in main awk script to `now`, as used in the
`--add` awk script, use constant regular expression instead of string,
and add double quotes to shell script variables.

There are minor changes from smart-case to the original "prefer case
sensitive" implementation.

Considering these directories with their respective 'frecencies':

     3          /tmp/foo/bar
     5          /tmp/foo/Baz
     8          /tmp/Baz
     13         /tmp/bar
     21         /tmp

These would be the results of different queries with the two approaches,
considering a filesystem that allows directories with same names and
different cases:

| query | smart-case   | prefer case sensitive |
|-------|--------------|-----------------------|
| tm    | /tmp         | /tmp                  |
| Tm    | (nothing)    | /tmp                  |
| ba    | /tmp/bar     | /tmp/bar              |
| Ba    | /tmp/Baz     | /tmp/Baz              |
| fo ba | /tmp/foo/Baz | /tmp/foo/bar          |
| fo Ba | /tmp/foo/Baz | /tmp/foo/Baz          |

Fixes rupa#209

README

@@ -6,7 +6,7 @@ NAME
        z - jump around
 
 SYNOPSIS
-       z [-chlrtx] [regex1 regex2 ... regexn]
+       z [-cehilrstx] [regex1 regex2 ... regexn]
 
 AVAILABILITY
        bash, zsh
@@ -16,7 +16,8 @@ DESCRIPTION
 
        After  a  short  learning  phase, z will take you to the most 'frecent'
        directory that matches ALL of the regexes given on the command line, in
-       order.
+       order. By default, smart case sensitivity is used, namely case insensi-
+       tive match when regexes are lower case, case sensitive match otherwise.
 
        For example, z foo bar would match /foo/bar but not /bar/foo.
 
@@ -27,10 +28,14 @@ OPTIONS
 
        -h     show a brief help message
 
+       -i     case insensitive match
+
        -l     list only
 
        -r     match by rank only
 
+       -s     case sensitive match
+
        -t     match by recent access only
 
        -x     remove the current directory from the datafile

z.1

@@ -4,7 +4,7 @@ NAME
 z \- jump around
 .SH
 SYNOPSIS
-z [\-chlrtx] [regex1 regex2 ... regexn]
+z [\-cehilrstx] [regex1 regex2 ... regexn]
 .SH
 AVAILABILITY
 bash, zsh
@@ -14,6 +14,8 @@ Tracks your most used directories, based on 'frecency'.
 .P
 After a short learning phase, \fBz\fR will take you to the most 'frecent'
 directory that matches ALL of the regexes given on the command line, in order.
+By default, smart case sensitivity is used, namely case insensitive match when
+regexes are lower case, case sensitive match otherwise.
 
 For example, \fBz foo bar\fR would match \fB/foo/bar\fR but not \fB/bar/foo\fR.
 .SH
@@ -28,12 +30,18 @@ echo the best match, don't cd
 \fB\-h\fR
 show a brief help message
 .TP
+\fB\-i\fR
+case insensitive match
+.TP
 \fB\-l\fR
 list only
 .TP
 \fB\-r\fR
 match by rank only
 .TP
+\fB\-s\fR
+case sensitive match
+.TP
 \fB\-t\fR
 match by recent access only
 .TP

z.sh

@@ -111,18 +111,20 @@ _z() {
     else
         # list/go
         while [ "$1" ]; do case "$1" in
-            --) while [ "$1" ]; do shift; local fnd="$fnd${fnd:+ }$1";done;;
-            -*) local opt=${1:1}; while [ "$opt" ]; do case ${opt:0:1} in
+            --) while [ "$1" ]; do shift; local fnd="$fnd${fnd:+ }$1"; done;;
+            -*) local opt="${1:1}"; while [ "$opt" ]; do case "${opt:0:1}" in
                     c) local fnd="^$PWD $fnd";;
                     e) local echo=echo;;
-                    h) echo "${_Z_CMD:-z} [-cehlrtx] args" >&2; return;;
+                    h) echo "${_Z_CMD:-z} [-cehilrstx] [regex1 regex2 ... regexn]" >&2; return;;
+                    i) local cas='i';;
                     l) local list=1;;
-                    r) local typ="rank";;
-                    t) local typ="recent";;
+                    r) local typ='r';;
+                    s) local cas='s';;
+                    t) local typ='t';;
                     x) sed -i -e "\:^${PWD}|.*:d" "$datafile";;
-                esac; opt=${opt:1}; done;;
+                esac; opt="${opt:1}"; done;;
              *) local fnd="$fnd${fnd:+ }$1";;
-        esac; local last=$1; [ "$#" -gt 0 ] && shift; done
+        esac; local last="$1"; [ "$#" -gt 0 ] && shift; done
         [ "$fnd" -a "$fnd" != "^$PWD " ] || local list=1
 
         # if we hit enter on a completion just go there
@@ -135,10 +137,10 @@ _z() {
         [ -f "$datafile" ] || return
 
         local cd
-        cd="$( < <( _z_dirs ) awk -v t="$(date +%s)" -v list="$list" -v typ="$typ" -v q="$fnd" -F"|" '
+        cd="$( < <( _z_dirs ) awk -v now="$(date +%s)" -v cas="$cas" -v list="$list" -v typ="$typ" -v q="$fnd" -F'|' '
             function frecent(rank, time) {
                 # relate frequency and time
-                dx = t - time
+                dx = now - time
                 if( dx < 3600 ) return rank * 4
                 if( dx < 86400 ) return rank * 2
                 if( dx < 604800 ) return rank / 2
@@ -175,33 +177,32 @@ _z() {
                 return short
             }
             BEGIN {
-                gsub(" ", ".*", q)
-                hi_rank = ihi_rank = -9999999999
+                if( cas == "i" ) {
+                    q = tolower(q)
+                    imatch = 1
+                } else if( cas != "s" && q == tolower(q) ) imatch = 1
+                gsub(/ /, ".*", q)
+                hi_rank = -9999999999
             }
             {
-                if( typ == "rank" ) {
+                if( typ == "r" ) {
                     rank = $2
-                } else if( typ == "recent" ) {
-                    rank = $3 - t
+                } else if( typ == "t" ) {
+                    rank = $3 - now
                 } else rank = frecent($2, $3)
-                if( $1 ~ q ) {
+                if( imatch ) {
+                    x = tolower($1)
+                } else x = $1
+                if( x ~ q ) {
                     matches[$1] = rank
-                } else if( tolower($1) ~ tolower(q) ) imatches[$1] = rank
-                if( matches[$1] && matches[$1] > hi_rank ) {
-                    best_match = $1
-                    hi_rank = matches[$1]
-                } else if( imatches[$1] && imatches[$1] > ihi_rank ) {
-                    ibest_match = $1
-                    ihi_rank = imatches[$1]
+                    if( rank > hi_rank ) {
+                        best_match = $1
+                        hi_rank = rank
+                    }
                 }
             }
             END {
-                # prefer case sensitive
-                if( best_match ) {
-                    output(matches, best_match, common(matches))
-                } else if( ibest_match ) {
-                    output(imatches, ibest_match, common(imatches))
-                }
+                output(matches, best_match, common(matches))
             }
         ')"