1#
2# Test whether $ZSH_VERSION (or some value of your choice, if a second argument
3# is provided) is greater than or equal to x.y.z-r (in argument one). In fact,
4# it'll accept any dot/dash-separated string of numbers as its second argument
5# and compare it to the dot/dash-separated first argument. Leading non-number
6# parts of a segment (such as the "zefram" in 3.1.2-zefram4) are not considered
7# when the comparison is done; only the numbers matter. Any left-out segments
8# in the first argument that are present in the version string compared are
9# considered as zeroes, eg 3 == 3.0 == 3.0.0 == 3.0.0.0 and so on.
10#
11# Usage examples:
12# is-at-least 3.1.6-15 && setopt NO_GLOBAL_RCS
13# is-at-least 3.1.0 && setopt HIST_REDUCE_BLANKS
14# is-at-least 586 $MACHTYPE && echo 'You could be running Mandrake!'
15# is-at-least $ZSH_VERSION || print 'Something fishy here.'
16#
17# Note that segments that contain no digits at all are ignored, and leading
18# text is discarded if trailing digits follow, because this was the meaning
19# of certain zsh version strings in the early 2000s.  Other segments that
20# begin with digits are compared using NUMERIC_GLOB_SORT semantics, and any
21# other segments starting with text are compared lexically.
22
23emulate -L zsh
24
25local IFS=".-" min_cnt=0 ver_cnt=0 part min_ver version order
26
27min_ver=(${=1})
28version=(${=2:-$ZSH_VERSION} 0)
29
30while (( $min_cnt <= ${#min_ver} )); do
31  while [[ "$part" != <-> ]]; do
32    (( ++ver_cnt > ${#version} )) && return 0
33    if [[ ${version[ver_cnt]} = *[0-9][^0-9]* ]]; then
34      # Contains a number followed by text.  Not a zsh version string.
35      order=( ${version[ver_cnt]} ${min_ver[ver_cnt]} )
36      if [[ ${version[ver_cnt]} = <->* ]]; then
37        # Leading digits, compare by sorting with numeric order.
38        [[ $order != ${${(On)order}} ]] && return 1
39      else
40        # No leading digits, compare by sorting in lexical order.
41        [[ $order != ${${(O)order}} ]] && return 1
42      fi
43      [[ $order[1] != $order[2] ]] && return 0
44    fi
45    part=${version[ver_cnt]##*[^0-9]}
46  done
47
48  while true; do
49    (( ++min_cnt > ${#min_ver} )) && return 0
50    [[ ${min_ver[min_cnt]} = <-> ]] && break
51  done
52
53  (( part > min_ver[min_cnt] )) && return 0
54  (( part < min_ver[min_cnt] )) && return 1
55  part=''
56done
57