Allow to disable String.Chars implementation for Geo objects

[Aethelflaed]

Hello,

I'm using geo_postgis for a web application in which I store GPS coordinates and I would like to change the default string representation of a Geo.Point, as WKT is not well-known enough for end-user.

This small change would allow me to disable the default String.Chars implementation by simply adding the following config:

config :geo, impl_to_string: false

The default behavior of the project is not changed at all.

[aseigo]

Perhaps it would be nice to allow to over-ride the individual implementations with a module in the config, so you could provide your own, per-type-String.Chars-impl. With macros this should be entirely compile-time, so should not impact performance, but give the needed flexibility ... just a thought :)

[bryanjos]

Sorry for just getting to this. I think I'm going to push back on this and say to either find a different way to print the string or we should just remove the implementation of String.Chars here altogether.

I think I'm fine with removing it completely

[aseigo]

I have implemented a configurable version of this feature, which can be seen in my branch here:

https://github.com/aseigo/geo/tree/customizable_string_chars_impls

I will send a push request once my other pending PR is handled ...

[bryanjos]

I guess for now it may be a good idea to allow it to be configurable. I'll accept a PR for it

[Aethelflaed]

I'm still quite new to Elixir so I didn't really know what you had in mind (or how exactly to do it), but I like what you've done!

[bryanjos]

Sorry there are some conflicts here, but if you can resolve those, I'll merge this

[bryanjos]

I implemented this in master since there was a conflict here.

[Aethelflaed]

Thank you, sorry for the long reaction :)

I was actually speaking about @aseigo 's implementation, but I guess it could be implemented later anyway