Dynamic bindings in scope

dynamic.sc

let model model-normal =
    static mat4
    static mat3

typefn& Node 'render (self)
    dynamic-let model model-normal =
        'transform model self.transform
        'transform model-normal self.transform-normal
    if ('is-leaf self)
        render-mesh self.mesh model model-normal
    else
        for child in self.children
            'render child

explicit.sc

let model model-normal =
    static mat4
    static mat3

typefn& Node 'render (self)
    let old-model old-model-normal =
        deref model
        deref model-normal
    model =
        'transform model self.transform
    model-normal =
        'transform model-normal self.transform-normal
    if ('is-leaf self)
        render-mesh self.mesh model model-normal
    else
        for child in self.children
            'render child
    model = old-model
    model-normal = old-model-normal

pass-around.sc

typefn& Node 'render (self model model-normal)
    let model model-normal =
        'transform model self.transform
        'transform model-normal self.transform-normal
    if ('is-leaf self)
        render-mesh self.mesh model model-normal
    else
        for child in self.children
            'render child model model-normal

dynamic:
this version uses the new scope-macro dynamic-let, which temporary changes the globals for the current scope

explicit:
this version does exactly the same, but without the use of the new scope macro, but instead typing everything explicitly

pass-around:
this version does the same, but passes everything around instead of using global variables
this doesn't need global variables, but you have to pass everything around
it may get inconvenient when having too many global variables
you may pack these variables into a struct or pass them around as variadic arguments, which will make it more convenient to pass around, but it's still necessary to pass it around at all
the problem when using a struct is, that you either have to revert the state anyway or you have a copy, where most of the variables are just the same
it's also more difficult to write generic code, when the API is not intended to use some global state, but you need global state in your use case