grade selection syntax about grassmann.jl HOT 6 OPEN

No, you are mistaken. That is not a grade selection syntax. The grade selection syntax is handled with the grade function:

julia> grade(v1+v2,0)
𝟎

julia> grade(v1+v2,Val(0))
𝟎

The scalar part of an element is obtained with the scalar function:

julia> scalar(v1+v2)
𝟎

Note that you may have to use Grassmann v0.8 or later to reproduce these exact results.

from grassmann.jl.

That still doesn't work for me, I get a method error

MethodError: no method matching grade(::Grassmann.MultiVector{⟨1,1,1⟩, Int64, 8})

I'm importing using Grassmann, LinearAlgebra, AbstractTensors, Leibniz

from grassmann.jl.

Also, your documentation reads:

Taking a projection into a specific grade of a MultiVector is usually written $\langle A\rangle_n$
​
and can be done using the soft brackets, like so

julia> A(0)
1v

julia> A(1)
2v₁ + 0v₂ + 0v₃

julia> A(2)
3v₁₂ + 0v₁₃ + 0v₂₃

Which is the only example of selecting elements of a grade I can find, and it fails if the type happens to be a Chain rather than a MultiVector

from grassmann.jl.

That still doesn't work for me, I get a method error
MethodError: no method matching grade(::Grassmann.MultiVector{⟨1,1,1⟩, Int64, 8})

Are you using Grassmann v0.8? That's the only currently supported version of Grassmann older versions are not supported.

Also, your documentation reads:
...
and can be done using the soft brackets, like so

No, converting \langle and \rangle sandwhich into a parenthesis prefix argument form is grammatically not implied anywhere.

from grassmann.jl.

The line which shows this syntax in your documentation is here.

from grassmann.jl.

I see, this is why I don't want to document any features that are works in progress. This package is not v1.0 yet, and is basically my scratch pad which is ever evolving. The syntax for grade selection is not yet firmly settled on a standard and is in flux.

from grassmann.jl.