A Nimble module when you need a parachute !

This is a simple Nimble module that uses that uses tag tracking to track usage of addr, cast, unsafeAddr.

It also defines unsafe template that simple {.push: tags[Unsafe].} to the scope.

Parachute defines castTag, addrTag and unsafeAddrTag, that simply calls the system version while adding tags: [Unsafe].

Once the tags is present, it is trivial to allow/forbid tags at compile time. Read Nim's manual for more detailed information.

To avoid having to change too much your code, there is a small macro openParachute() which declare addr and unsafeAddr as templates. Since addr cannot be overloaded, it will have to be excluded from system.

In short, if you want to use the tagged version of addr and unsafeAddr do the following in your file :

import system except addr
import parachute
openParachute

This way of doing things avoid exporting addr``and ``unsafeAddr identifier that would potentially collide.

Since cast is a keyword of the language, it cannot be replaced or used as an identifier. This means that for use the tagged version of cast you have to explicitly call castTag.

But since cast is most often called in conjonction with addr or unsafeAddr, it should be too impactful.

The documentation is accessible here .

Look into the tests/ folder for more elaborate examples.

What really would improve this concept would be:

• Being able to remove a tag. This would make wrapping unsafe code a breeze !
• Being able to "forbid" a tag without filtering every offet effects. Something like {.tags: [not Unsafe].} to explicitly forbid a tags without failing to compile on others.