search_and_replace.jl

using MacroTools, MLStyle, Test

subst(a) = MLStyle.@match a begin
    :(sin($x)) => :(cos($x + 1))
    _ => a
end
MacroTools.prewalk(subst, quote
    sin(x + sin(x))
end)
 

macro search_and_replace2(ex, s, r)

    ex = Expr(:quote, ex)
    s = Expr(:quote, s)
    r = Expr(:quote, r)
    esc(quote
        subst(a) = MLStyle.@match a begin
            $s => $r
            _ => a
        end
        MacroTools.prewalk(subst, $ex)
    end)
end

ex = @search_and_replace2 sin(x) sin(x) cos(x)
@test ex == :( cos(x) )

ex = @search_and_replace2 sin(y) sin($x) cos($x)
@test ex == :( cos(y) )

ex = @search_and_replace2 sin(sin(x)) sin($x) cos($x +1)
@test ex == :( cos(cos(x+1) +1) )