Interpolate into macro like BenchmarkTools

chakravala · December 10, 2018, 3:55am

With @btime it is possible to interpolate values, how can I replicate this in other macros?

julia> x = 8
8

julia> @btime $x
  0.027 ns (0 allocations: 0 bytes)
8

julia> macro fun(expr)
           return esc(expr)
       end
@fun (macro with 1 method)

julia> @fun $x
ERROR: syntax: "$" expression outside quote

tkoolen · December 10, 2018, 5:45am

The $ thing is specific to BenchmarkTools:

github.com

JuliaCI/BenchmarkTools.jl/blob/af35d0513fe1e336ad0d8b9a35f924e8461aefa2/src/execution.jl#L191-L206


      
          function quasiquote!(ex::Expr, vars::Vector{Expr})
              if ex.head === :($)
                  lhs = ex.args[1]
                  rhs = isa(lhs, Symbol) ? gensym(lhs) : gensym()
                  push!(vars, Expr(:(=), rhs, ex))
                  return rhs
              elseif ex.head !== :quote
                  for i in 1:length(ex.args)
                      arg = ex.args[i]
                      if isa(arg, Expr)
                          ex.args[i] = quasiquote!(arg, vars)
                      end
                  end
              end
              return ex
          end

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Interpolate into macro like BenchmarkTools

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