How to get CARGO_PKG_VERSION inside justfile?

[Boscop]

I have a cmd in my justfile to package my release binary in a zip file, and I want to name the zip file after the CARGO_PKG_VERSION. How can I read the value of CARGO_PKG_VERSION in the justfile? :)

[casey]

There isn't direct support in Just for this, but I use the following to extract the crate version into a variable:

version := `sed -En 's/version[[:space:]]*=[[:space:]]*"([^"]+)"/v\1/p' Cargo.toml | head -1`

Does that work for your use case?

[Boscop]

@casey Thanks! This works:

version_subcrate := `sed -En 's/version[[:space:]]*=[[:space:]]*"([^"]+)"/v\1/p' subcrate/Cargo.toml | head -1`

pkg-subcrate:
    echo {{version_subcrate}}

But is there a way I can make this reuseable as a function, callable like version(subcrate)?
Because I have several binary subcrates and need this for all of them.

[casey]

There isn't currently a way to define functions, although I could imagine letting recipes be called as functions in expressions though:

version SUBCRATE:
    sed -En 's/version[[:space:]]*=[[:space:]]*"([^"]+)"/v\1/p' {{SUBCRATE}}/Cargo.toml | head -1

pkg-foo:
  echo {{version("foo")}}

One issue with this is that currently, Just doesn't really have a type system. Or, rather, the only type of value are strings, and a small number of built-in functions types which are special cased.

If it were possible to define functions, then these functions would have different arities, and validating statically that functions are called with the correct number of arguments might be tricky. (I would strongly prefer to do static type checking over dynamic, even though doing it dynamically would probably be easier.)