codegen.jl

julia> abstract type Expr end

julia> struct Apply <: Expr
       f::Expr
       arg::Expr
       end

julia> struct Var <: Expr
       name::Symbol
       end

julia> match_f(x) = Match.@match x begin
       Apply(Var(f), Apply(Var(g), Var(a))) => (f,g,a)
       end
match_f (generic function with 1 method)

julia> rematch_f(x) = Rematch.@match x begin
       Apply(Var(f), Apply(Var(g), Var(a))) => (f,g,a)
       end
rematch_f (generic function with 1 method)

julia> match_f(Apply(Var(:inc), Apply(Var(:double), Var(:x))))
(:inc, :double, :x)

julia> rematch_f(Apply(Var(:inc), Apply(Var(:double), Var(:x))))
(:inc, :double, :x)

julia> @code_warntype match_f(Apply(Var(:inc), Apply(Var(:double), Var(:x))))
Variables:
  #self# <optimized out>
  x::Apply
  a::Any
  g::Any
  f::Any
  v#756 <optimized out>
  #temp#@_7::Bool
  #temp#@_8::Bool
  #temp#@_9::Bool
  #temp#@_10::Bool
  #temp#@_11::Bool
  #temp#@_12::Bool
  #temp#@_13::Bool
  #temp#@_14::Bool
  #temp#@_15::Bool

Body:
  begin 
      # meta: location /home/jamie/.julia/v0.6/Match/src/matchmacro.jl # line 438:
      # meta: location REPL[84] # line 2:
      SSAValue(2) = $(Expr(:invoke, MethodInstance for fieldnames(::DataType), :(Main.fieldnames), :(Main.Apply)))
      unless ((Base.arraylen)(SSAValue(2))::Int64 === 2)::Bool goto 55
      unless ((Main.getfield)(x::Apply, 1)::Expr isa Main.Var)::Bool goto 50
      SSAValue(3) = $(Expr(:invoke, MethodInstance for fieldnames(::DataType), :(Main.fieldnames), :(Main.Var)))
      unless ((Base.arraylen)(SSAValue(3))::Int64 === 1)::Bool goto 45
      unless ((Main.getfield)(x::Apply, 2)::Expr isa Main.Apply)::Bool goto 40
      SSAValue(4) = $(Expr(:invoke, MethodInstance for fieldnames(::DataType), :(Main.fieldnames), :(Main.Apply)))
      unless ((Base.arraylen)(SSAValue(4))::Int64 === 2)::Bool goto 35
      unless ((Main.getfield)((Main.getfield)(x::Apply, 2)::Expr, 1)::Any isa Main.Var)::Bool goto 30
      SSAValue(5) = $(Expr(:invoke, MethodInstance for fieldnames(::DataType), :(Main.fieldnames), :(Main.Var)))
      unless ((Base.arraylen)(SSAValue(5))::Int64 === 1)::Bool goto 25
      unless ((Main.getfield)((Main.getfield)(x::Apply, 2)::Expr, 2)::Any isa Main.Var)::Bool goto 20
      SSAValue(6) = $(Expr(:invoke, MethodInstance for fieldnames(::DataType), :(Main.fieldnames), :(Main.Var)))
      #temp#@_15::Bool = ((Base.arraylen)(SSAValue(6))::Int64 === 1)::Bool
      goto 22
      20: 
      #temp#@_15::Bool = false
      22: 
      #temp#@_14::Bool = #temp#@_15::Bool
      goto 27
      25: 
      #temp#@_14::Bool = false
      27: 
      #temp#@_13::Bool = #temp#@_14::Bool
      goto 32
      30: 
      #temp#@_13::Bool = false
      32: 
      #temp#@_12::Bool = #temp#@_13::Bool
      goto 37
      35: 
      #temp#@_12::Bool = false
      37: 
      #temp#@_11::Bool = #temp#@_12::Bool
      goto 42
      40: 
      #temp#@_11::Bool = false
      42: 
      #temp#@_10::Bool = #temp#@_11::Bool
      goto 47
      45: 
      #temp#@_10::Bool = false
      47: 
      #temp#@_9::Bool = #temp#@_10::Bool
      goto 52
      50: 
      #temp#@_9::Bool = false
      52: 
      #temp#@_8::Bool = #temp#@_9::Bool
      goto 57
      55: 
      #temp#@_8::Bool = false
      57: 
      #temp#@_7::Bool = #temp#@_8::Bool
      goto 60
      60: 
      unless #temp#@_7::Bool goto 70
      # meta: location /home/jamie/.julia/v0.6/Match/src/matchmacro.jl # line 390:
      f::Any = (Main.getfield)((Main.getfield)(x::Apply, 1)::Expr, 1)::Any
      g::Any = (Main.getfield)((Main.getfield)((Main.getfield)(x::Apply, 2)::Expr, 1)::Any, 1)::Any
      a::Any = (Main.getfield)((Main.getfield)((Main.getfield)(x::Apply, 2)::Expr, 2)::Any, 1)::Any
      SSAValue(0) = (Core.tuple)(f::Any, g::Any, a::Any)::Tuple{Any,Any,Any}
      # meta: pop location
      return SSAValue(0)
      70: 
      # meta: location /home/jamie/.julia/v0.6/Match/src/matchmacro.jl # line 392:
      SSAValue(1) = Main.nothing
      # meta: pop location
      # meta: pop location
      # meta: pop location
      return SSAValue(1)
  end::Union{Tuple{Any,Any,Any}, Void}

julia> @code_warntype rematch_f(Apply(Var(:inc), Apply(Var(:double), Var(:x))))
Variables:
  #self# <optimized out>
  x::Apply
  value <optimized out>
  value_1::Expr
  value_1_1::Symbol
  variable_f::Symbol
  value_2::Expr
  value_2_1::Expr
  value_2_1_1::Symbol
  variable_g::Symbol
  value_2_2::Expr
  value_2_2_1::Symbol
  variable_a::Symbol
  f::Symbol
  a::Symbol
  g::Symbol
  #temp#@_17::Bool
  #temp#@_18::Bool
  #temp#@_19::Bool
  #temp#@_20::Bool
  #temp#@_21::Bool
  #temp#@_22::Bool
  #temp#@_23::Bool
  #temp#@_24::Bool
  #temp#@_25::Bool
  #temp#@_26::Bool
  #temp#@_27::Bool
  #temp#@_28::Bool
  #temp#@_29::Bool

Body:
  begin 
      NewvarNode(:(value_1::Expr))
      NewvarNode(:(value_1_1::Symbol))
      NewvarNode(:(variable_f::Symbol))
      NewvarNode(:(value_2::Expr))
      NewvarNode(:(value_2_1::Expr))
      NewvarNode(:(value_2_1_1::Symbol))
      NewvarNode(:(variable_g::Symbol))
      NewvarNode(:(value_2_2::Expr))
      NewvarNode(:(value_2_2_1::Symbol))
      NewvarNode(:(variable_a::Symbol))
      NewvarNode(:(f::Symbol))
      NewvarNode(:(a::Symbol))
      NewvarNode(:(g::Symbol))
      # meta: location /home/jamie/.julia/v0.6/Rematch/src/Rematch.jl # line 109:
      $(Expr(:invoke, MethodInstance for assert_num_fields(::Type{Apply}, ::Int64), :(Rematch.assert_num_fields), :(Main.Apply), 2)) # line 109:
      $(Expr(:invoke, MethodInstance for assert_num_fields(::Type{Var}, ::Int64), :(Rematch.assert_num_fields), :(Main.Var), 1)) # line 109:
      $(Expr(:invoke, MethodInstance for assert_num_fields(::Type{Apply}, ::Int64), :(Rematch.assert_num_fields), :(Main.Apply), 2)) # line 109:
      $(Expr(:invoke, MethodInstance for assert_num_fields(::Type{Var}, ::Int64), :(Rematch.assert_num_fields), :(Main.Var), 1)) # line 109:
      $(Expr(:invoke, MethodInstance for assert_num_fields(::Type{Var}, ::Int64), :(Rematch.assert_num_fields), :(Main.Var), 1)) # line 112:
      unless (2 === 2)::Bool goto 116 # line 44:
      value_1::Expr = (Rematch.getfield)(x::Apply, 1)::Expr # line 112:
      unless (value_1::Expr isa Main.Var)::Bool goto 44
      unless (1 === 1)::Bool goto 39 # line 44:
      value_1_1::Symbol = (Rematch.getfield)(value_1::Var, 1)::Symbol # line 76:
      variable_f::Symbol = value_1_1::Symbol # line 77:
      #temp#@_20::Bool = true
      goto 41
      39: 
      #temp#@_20::Bool = false
      41: 
      #temp#@_19::Bool = #temp#@_20::Bool
      goto 46
      44: 
      #temp#@_19::Bool = false
      46: 
      unless #temp#@_19::Bool goto 111 # line 44:
      value_2::Expr = (Rematch.getfield)(x::Apply, 2)::Expr # line 112:
      unless (value_2::Expr isa Main.Apply)::Bool goto 106
      unless (2 === 2)::Bool goto 101 # line 44:
      value_2_1::Expr = (Rematch.getfield)(value_2::Apply, 1)::Expr # line 112:
      unless (value_2_1::Expr isa Main.Var)::Bool goto 70
      unless (1 === 1)::Bool goto 65 # line 44:
      value_2_1_1::Symbol = (Rematch.getfield)(value_2_1::Var, 1)::Symbol # line 76:
      variable_g::Symbol = value_2_1_1::Symbol # line 77:
      #temp#@_25::Bool = true
      goto 67
      65: 
      #temp#@_25::Bool = false
      67: 
      #temp#@_24::Bool = #temp#@_25::Bool
      goto 72
      70: 
      #temp#@_24::Bool = false
      72: 
      unless #temp#@_24::Bool goto 96 # line 44:
      value_2_2::Expr = (Rematch.getfield)(value_2::Apply, 2)::Expr # line 112:
      unless (value_2_2::Expr isa Main.Var)::Bool goto 91
      unless (1 === 1)::Bool goto 86 # line 44:
      value_2_2_1::Symbol = (Rematch.getfield)(value_2_2::Var, 1)::Symbol # line 76:
      variable_a::Symbol = value_2_2_1::Symbol # line 77:
      #temp#@_28::Bool = true
      goto 88
      86: 
      #temp#@_28::Bool = false
      88: 
      #temp#@_27::Bool = #temp#@_28::Bool
      goto 93
      91: 
      #temp#@_27::Bool = false
      93: 
      #temp#@_26::Bool = #temp#@_27::Bool
      goto 98
      96: 
      #temp#@_26::Bool = false
      98: 
      #temp#@_23::Bool = #temp#@_26::Bool
      goto 103
      101: 
      #temp#@_23::Bool = false
      103: 
      #temp#@_22::Bool = #temp#@_23::Bool
      goto 108
      106: 
      #temp#@_22::Bool = false
      108: 
      #temp#@_21::Bool = #temp#@_22::Bool
      goto 113
      111: 
      #temp#@_21::Bool = false
      113: 
      #temp#@_18::Bool = #temp#@_21::Bool
      goto 118
      116: 
      #temp#@_18::Bool = false
      118: 
      #temp#@_17::Bool = #temp#@_18::Bool
      goto 121
      121: 
      unless #temp#@_17::Bool goto 132 # line 146:
      f::Symbol = variable_f::Symbol # line 146:
      a::Symbol = variable_a::Symbol # line 146:
      g::Symbol = variable_g::Symbol # line 148:
      #temp#@_29::Bool = true
      goto 134
      132: 
      #temp#@_29::Bool = false
      134: 
      unless #temp#@_29::Bool goto 138 # line 172:
      return (Core.tuple)(f::Symbol, g::Symbol, a::Symbol)::Tuple{Symbol,Symbol,Symbol}
      138:  # line 174:
      (Rematch.throw)($(Expr(:new, :(Rematch.MatchFailure), :(x))))::Union{}
      # meta: pop location
  end::Tuple{Symbol,Symbol,Symbol}

julia> @benchmark match_f($Apply(Var(:inc), Apply(Var(:double), Var(:x))))
BenchmarkTools.Trial: 
  memory estimate:  624 bytes
  allocs estimate:  11
  --------------
  minimum time:     1.447 μs (0.00% GC)
  median time:      1.499 μs (0.00% GC)
  mean time:        1.624 μs (3.28% GC)
  maximum time:     310.933 μs (96.93% GC)
  --------------
  samples:          10000
  evals/sample:     10

julia> @benchmark rematch_f($Apply(Var(:inc), Apply(Var(:double), Var(:x))))
BenchmarkTools.Trial: 
  memory estimate:  624 bytes
  allocs estimate:  11
  --------------
  minimum time:     1.244 μs (0.00% GC)
  median time:      1.266 μs (0.00% GC)
  mean time:        1.396 μs (3.49% GC)
  maximum time:     255.502 μs (97.89% GC)
  --------------
  samples:          10000
  evals/sample:     10