simplify process of printing UnionAll type-variables

Since UnionAll bounds are encountered recursively,
it's easiest to represent this the same way in the IOContext.

Also avoid the performance / allocation overhead of using
`IOContext(io)` as a no-op convert (not a no-op since keyword support was added)

base/methodshow.jl

@@ -44,7 +44,7 @@ end
 
 function arg_decl_parts(m::Method)
  tv = m.tvars
- if !isa(tv,SimpleVector)
+ if !isa(tv, SimpleVector)
  tv = Any[tv]
  else
  tv = Any[tv...]
@@ -59,7 +59,11 @@ function arg_decl_parts(m::Method)
  if src !== nothing && src.slotnames !== nothing
  argnames = src.slotnames[1:m.nargs]
  sig = unwrap_unionall(m.sig)
- decls = Any[argtype_decl(:tvar_env => tv, argnames[i], sig, i, m.nargs, m.isva)
+ show_env = ImmutableDict{Symbol, Any}()
+ for t in tv
+ show_env = ImmutableDict(show_env, :unionall_env => t)
+ end
+ decls = Any[argtype_decl(show_env, argnames[i], sig, i, m.nargs, m.isva)
  for i = 1:m.nargs]
  else
  decls = Any[("", "") for i = 1:length(unwrap_unionall(m.sig).parameters)]

base/multimedia.jl

@@ -39,7 +39,7 @@ mimewritable{mime}(::MIME{mime}, x) =
 show(io::IO, m::AbstractString, x) = show(io, MIME(m), x)
 mimewritable(m::AbstractString, x) = mimewritable(MIME(m), x)
 
-verbose_show(io, m, x) = show(IOContext(io,limit=false), m, x)
+verbose_show(io, m, x) = show(IOContext(io, :limit => false), m, x)
 
 """
  reprmime(mime, x)

base/range.jl

@@ -254,7 +254,7 @@ function print_range(io::IO, r::Range,
  limit = get(io, :limit, false)
  sz = displaysize(io)
  if !haskey(io, :compact)
- io = IOContext(io, compact=true)
+ io = IOContext(io, :compact => true)
  end
  screenheight, screenwidth = sz[1] - 4, sz[2]
  screenwidth -= length(pre) + length(post)

base/replutil.jl

@@ -39,7 +39,7 @@ function show{K,V}(io::IO, ::MIME"text/plain", t::Associative{K,V})
  recur_io = IOContext(io, :SHOWN_SET => t)
  limit::Bool = get(io, :limit, false)
  if !haskey(io, :compact)
- recur_io = IOContext(recur_io, compact=true)
+ recur_io = IOContext(recur_io, :compact => true)
  end
 
  print(io, summary(t))

base/show.jl

@@ -24,21 +24,24 @@ end
 
 The same as `IOContext(io::IO, KV::Pair)`, but accepting properties as keyword arguments.
 """
-IOContext(io::IO; kws...) = IOContext(IOContext(io, ImmutableDict{Symbol,Any}()); kws...)
+IOContext(io::IO; kws...) = IOContext(convert(IOContext, io); kws...)
 function IOContext(io::IOContext; kws...)
  for (k, v) in kws
  io = IOContext(io, k, v)
  end
- io
+ return io
 end
 
+convert(::Type{IOContext}, io::IOContext) = io
+convert(::Type{IOContext}, io::IO) = IOContext(io, ImmutableDict{Symbol, Any}())
+
 IOContext(io::IOContext, dict::ImmutableDict) = typeof(io)(io.io, dict)
 IOContext(io::IO, dict::ImmutableDict) = IOContext{typeof(io)}(io, dict)
 
+IOContext(io::IOContext, key, value) = IOContext(io.io, ImmutableDict{Symbol, Any}(io.dict, key, value))
 IOContext(io::IO, key, value) = IOContext(io, ImmutableDict{Symbol, Any}(key, value))
-IOContext(io::IOContext, key, value) = IOContext(io, ImmutableDict{Symbol, Any}(io.dict, key, value))
 
-IOContext(io::IO, context::IO) = IOContext(io)
+IOContext(io::IO, context::IO) = convert(IOContext, io)
 
 """
  IOContext(io::IO, context::IOContext)
@@ -183,32 +186,14 @@ function show(io::IO, x::UnionAll)
  if print_without_params(x)
  return show(io, unwrap_unionall(x).name)
  end
- tvar_env = get(io, :tvar_env, false)
- if tvar_env !== false && isa(tvar_env, AbstractVector)
- tvar_env = Any[tvar_env..., x.var]
- else
- tvar_env = Any[x.var]
- end
- show(IOContext(io, tvar_env = tvar_env), x.body)
+ show(IOContext(io, :unionall_env => x.var), x.body)
  print(io, " where ")
  show(io, x.var)
 end
 
-function show_type_parameter(io::IO, p::ANY, has_tvar_env::Bool)
- if has_tvar_env
- show(io, p)
- else
- show(IOContext(io, :tvar_env, true), p)
- end
-end
-
 show(io::IO, x::DataType) = show_datatype(io, x)
 
 function show_datatype(io::IO, x::DataType)
- # tvar_env is a `::Vector{Any}` when we are printing a method signature
- # and `true` if we are printing type parameters outside a method signature.
- has_tvar_env = get(io, :tvar_env, false) !== false
-
  if (!isempty(x.parameters) || x.name === Tuple.name) && x !== Tuple
  n = length(x.parameters)
 
@@ -223,7 +208,7 @@ function show_datatype(io::IO, x::DataType)
  # since this information is still useful.
  print(io, '{')
  for (i, p) in enumerate(x.parameters)
- show_type_parameter(io, p, has_tvar_env)
+ show(io, p)
  i < n && print(io, ',')
  end
  print(io, '}')
@@ -1063,16 +1048,12 @@ function ismodulecall(ex::Expr)
 end
 
 function show(io::IO, tv::TypeVar)
- # If `tvar_env` exist and we are in it, the type constraint are
- # already printed and we don't need to print it again.
+ # If we are in the `unionall_env`, the type-variable is bound
+ # and the type constraints are already printed.
+ # We don't need to print it again.
  # Otherwise, the lower bound should be printed if it is not `Bottom`
  # and the upper bound should be printed if it is not `Any`.
- tvar_env = isa(io, IOContext) && get(io, :tvar_env, false)
- if isa(tvar_env, Vector{Any})
- in_env = (tv in tvar_env::Vector{Any})
- else
- in_env = false
- end
+ in_env = (:unionall_env => tv) in io
  function show_bound(io::IO, b::ANY)
  parens = isa(b,UnionAll) && !print_without_params(b)
  parens && print(io, "(")
@@ -1191,16 +1172,22 @@ function dump(io::IO, x::DataType, n::Int, indent)
  if x !== Any
  print(io, " <: ", supertype(x))
  end
- if !(x <: Tuple)
- tvar_io = IOContext(io, :tvar_env => Any[x.parameters...])
- fields = fieldnames(x)
- if n > 0
- for idx in 1:length(fields)
- println(io)
- print(io, indent, " ", fields[idx], "::")
- print(tvar_io, fieldtype(x, idx))
+ if n > 0 && !(x <: Tuple)
+ tvar_io::IOContext = io
+ for tparam in x.parameters
+ # approximately recapture the list of tvar parameterization
+ # that may be used by the internal fields
+ if isa(tparam, TypeVar)
+ tvar_io = IOContext(tvar_io, :unionall_env => tparam)
  end
  end
+ fields = fieldnames(x)
+ fieldtypes = x.types
+ for idx in 1:length(fields)
+ println(io)
+ print(io, indent, " ", fields[idx], "::")
+ print(tvar_io, fieldtypes[idx])
+ end
  end
  nothing
 end
@@ -1634,7 +1621,7 @@ function showarray(io::IO, X::AbstractArray, repr::Bool = true; header = true)
  return show_vector(io, X, "[", "]")
  end
  if !haskey(io, :compact)
- io = IOContext(io, compact=true)
+ io = IOContext(io, :compact => true)
  end
  if !repr && get(io, :limit, false) && eltype(X) === Method
  # override usual show method for Vector{Method}: don't abbreviate long lists

base/sparse/sparsematrix.jl

@@ -124,7 +124,8 @@ function Base.show(io::IO, ::MIME"text/plain", S::SparseMatrixCSC)
  end
 end
 
-function Base.show(io::IO, S::SparseMatrixCSC)
+Base.show(io::IO, S::SparseMatrixCSC) = Base.show(convert(IOContext, io), S::SparseMatrixCSC)
+function Base.show(io::IOContext, S::SparseMatrixCSC)
  if nnz(S) == 0
  return show(io, MIME("text/plain"), S)
  end
@@ -139,7 +140,6 @@ function Base.show(io::IO, S::SparseMatrixCSC)
  pad = ndigits(max(S.m,S.n))
  k = 0
  sep = "\n "
- io = IOContext(io)
  if !haskey(io, :compact)
  io = IOContext(io, :compact => true)
  end

base/sparse/sparsevector.jl

@@ -682,7 +682,8 @@ function show(io::IO, ::MIME"text/plain", x::AbstractSparseVector)
  show(io, x)
 end
 
-function show(io::IO, x::AbstractSparseVector)
+show(io::IO, x::AbstractSparseVector) = show(convert(IOContext, io), x)
+function show(io::IOContext, x::AbstractSparseVector)
  # TODO: make this a one-line form
  n = length(x)
  nzind = nonzeroinds(x)
@@ -693,7 +694,6 @@ function show(io::IO, x::AbstractSparseVector)
  half_screen_rows = limit ? div(displaysize(io)[1] - 8, 2) : typemax(Int)
  pad = ndigits(n)
  sep = "\n\t"
- io = IOContext(io)
  if !haskey(io, :compact)
  io = IOContext(io, :compact => true)
  end

doc/src/stdlib/io-network.md

@@ -51,7 +51,6 @@ Base.readavailable
 Base.IOContext
 Base.IOContext(::IO, ::Pair)
 Base.IOContext(::IO, ::IOContext)
-Base.IOContext(::IO)
 ```
 
 ## Text I/O

test/dict.jl

@@ -268,7 +268,7 @@ for d in (Dict("\n" => "\n", "1" => "\n", "\n" => "2"),
  for cols in (12, 40, 80), rows in (2, 10, 24)
  # Ensure output is limited as requested
  s = IOBuffer()
- io = Base.IOContext(s, limit=true, displaysize=(rows, cols))
+ io = Base.IOContext(Base.IOContext(s, :limit => true), :displaysize => (rows, cols))
  Base.show(io, MIME("text/plain"), d)
  out = split(String(take!(s)),'\n')
  for line in out[2:end]
@@ -278,7 +278,7 @@ for d in (Dict("\n" => "\n", "1" => "\n", "\n" => "2"),
 
  for f in (keys, values)
  s = IOBuffer()
- io = Base.IOContext(s, limit=true, displaysize=(rows, cols))
+ io = Base.IOContext(Base.IOContext(s, :limit => true), :displaysize => (rows, cols))
  Base.show(io, MIME("text/plain"), f(d))
  out = split(String(take!(s)),'\n')
  for line in out[2:end]
@@ -311,7 +311,7 @@ end
 type Alpha end
 Base.show(io::IO, ::Alpha) = print(io,"α")
 let sbuff = IOBuffer(),
- io = Base.IOContext(sbuff, limit=true, displaysize=(10, 20))
+ io = Base.IOContext(Base.IOContext(sbuff, :limit => true), :displaysize => (10, 20))
 
  Base.show(io, MIME("text/plain"), Dict(Alpha()=>1))
  @test !contains(String(sbuff), "…")

test/nullable.jl

@@ -103,13 +103,13 @@ for (i, T) in enumerate(types)
  @test String(take!(io1)) == @sprintf("Nullable{%s}(%s)", T, String(take!(io2)))
 
  a1 = [x2]
- show(IOContext(io1, compact=false), a1)
- show(IOContext(io2, compact=false), x2)
+ show(IOContext(io1, :compact => false), a1)
+ show(IOContext(io2, :compact => false), x2)
  @test String(take!(io1)) ==
  @sprintf("Nullable{%s}[%s]", string(T), String(take!(io2)))
 
  show(io1, a1)
- show(IOContext(io2, compact=true), x2)
+ show(IOContext(io2, :compact => true), x2)
  @test String(take!(io1)) ==
  @sprintf("Nullable{%s}[%s]", string(T), String(take!(io2)))
 end

test/offsetarray.jl

@@ -139,7 +139,7 @@ smry = summary(v)
 @test contains(smry, "OffsetArray{Float64,1")
 @test contains(smry, "with indices -1:1")
 function cmp_showf(printfunc, io, A)
- ioc = IOContext(io, limit=true, compact=true)
+ ioc = IOContext(IOContext(io, :limit => true), :compact => true)
  printfunc(ioc, A)
  str1 = String(take!(io))
  printfunc(ioc, parent(A))
@@ -162,9 +162,9 @@ targets2 = ["(1.0, 1.0)",
  "([1.0], [1.0])"]
 for n = 0:4
  a = OffsetArray(ones(Float64,ntuple(d->1,n)), ntuple(identity,n))
- show(IOContext(io, limit=true), MIME("text/plain"), a)
+ show(IOContext(io, :limit => true), MIME("text/plain"), a)
  @test String(take!(io)) == targets1[n+1]
- show(IOContext(io, limit=true), MIME("text/plain"), (a,a))
+ show(IOContext(io, :limit => true), MIME("text/plain"), (a,a))
  @test String(take!(io)) == targets2[n+1]
 end
 P = OffsetArray(rand(8,8), (1,1))

test/ranges.jl

@@ -595,7 +595,7 @@ end
 
 # stringmime/show should display the range or linspace nicely
 # to test print_range in range.jl
-replstrmime(x) = sprint((io,x) -> show(IOContext(io, limit=true), MIME("text/plain"), x), x)
+replstrmime(x) = sprint((io,x) -> show(IOContext(io, :limit => true), MIME("text/plain"), x), x)
 @test replstrmime(1:4) == "1:4"
 @test stringmime("text/plain", 1:4) == "1:4"
 @test stringmime("text/plain", linspace(1,5,7)) == "1.0:0.6666666666666666:5.0"

test/show.jl

@@ -4,7 +4,7 @@ const curmod = current_module()
 const curmod_name = fullname(curmod)
 const curmod_prefix = "$(["$m." for m in curmod_name]...)"
 
-replstr(x) = sprint((io,x) -> show(IOContext(io, limit=true), MIME("text/plain"), x), x)
+replstr(x) = sprint((io,x) -> show(IOContext(io, :limit => true), MIME("text/plain"), x), x)
 
 @test replstr(Array{Any}(2)) == "2-element Array{Any,1}:\n #undef\n #undef"
 @test replstr(Array{Any}(2,2)) == "2×2 Array{Any,2}:\n #undef #undef\n #undef #undef"
@@ -533,14 +533,14 @@ end
 
 # PR #16651
 @test !contains(repr(ones(10,10)), "\u2026")
-@test contains(sprint((io,x)->show(IOContext(io,:limit=>true), x), ones(30,30)), "\u2026")
+@test contains(sprint((io, x) -> show(IOContext(io, :limit => true), x), ones(30, 30)), "\u2026")
 
 # showcompact() also sets :multiline=>false (#16817)
 let io = IOBuffer()
  x = [1, 2]
  showcompact(io, x)
  @test String(take!(io)) == "[1, 2]"
- showcompact(IOContext(io, :compact=>true), x)
+ showcompact(IOContext(io, :compact => true), x)
  @test String(take!(io)) == "[1, 2]"
 end