On Fri, Dec 4, 2015 at 6:45 PM, TJ Luoma <luomat@gmail.com> wrote:

> Thanks to a recent tip from the list, I've started using 'is-at-least' to
> compare version numbers.
>
> However, I seem to have found a situation/edge case where it does not seem
> to work.
>
> I am trying to compare version numbers of software, in this case ImageOptim
> for the Mac.
>

`is-at-least` isn't intended to be that general.  From `man zshall`:

is-at-least needed [ present ]
    Perform  a  greater-than-or-equal-to  comparison of two strings having
the
    format of a zsh version number; that is, a string of numbers and text
with
    segments separated by dots or dashes.

To do so would require a great deal more complexity.  It'd probably be a
better check for a package manager (where the version strings can be
limited to a specific format).

The version I have installed is '1.6.1a1' where the 'a' is for 'alpha'
>
> There is a newer version '1.6.1b2' where the 'b' is for 'beta'
>
> ##
>
> LATEST_VERSION='1.6.1b2'
>
> INSTALLED_VERSION='1.6.1a1'
>
> autoload is-at-least
>
> is-at-least "$LATEST_VERSION" "$INSTALLED_VERSION"
>

For this specific case, the following seems reasonable:

LATEST_VERSION=1.6.1b2
INSTALLED_VERSION=1.6.1a1
alpha='(#b)([A-Za-z]##)'
is-at-least ${LATEST_VERSION//$~alpha/.$match[1].}
${INSTALLED_VERSION//$~alpha/.$match[1].}

'(#b)' in a pattern activates back references
'##' is the equivalent of '+' in most regular expression libraries
I think both of those require 'EXTENDED_GLOB'

The `~` in $~alpha means treat the contents of $alpha as a pattern, not
just a string to match
The $match[1] is the parenthesized group in the match (so, a string of
alphabetic characters).

-- 
Best,
Ben