match dot expression

[thautwarm]

JuliaLang/julia#6104 (comment)

There is a problem that QuoteNode would be automatically evaluated, so when source ast contains QuoteNode, pattern matching compilation generates the same QuoteNode and inserts it into the generated ast. The QuoteNode generated by pattern compilation would then be auto evaluated and finally we got a a != QuoteNode(a), in another words, matching fails.

To solve this problem we introduce a QuotePattern to avoid auto evaluation of QuoteNode generated by patterns.

Following the knowledge given by the the first referenced issue, this technically works.

[thautwarm]

Now we can write this:

using MLStyle

module Linq
    select(arr, f) = map(f, arr)
end

macro linq(expr)
    @match expr begin
        :($subject.$method($(args...))) =>
            let method = getfield(Linq, method)
                quote $method($subject, $(args...)) end
            end
        _ => @error "invalid"
    end
end

@assert (@linq [1, 2, 3].select(x -> x * 5)) == [5, 10,  15]

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done