Deprecate showcompact()

There is no obvious reason to provide a special function for the :compact IOContext property
but not for other properties. showcompact() used to be useful to print a single-line
representation of an array at the REPL, but now show() does the same thing. So it should only
be needed for collections to print their elements when implementing show(), and for tests
(most of the changes here).

Also improve a few docstrings.

NEWS.md

@@ -1061,7 +1061,11 @@ Deprecated or removed
   * The fallback method `^(x, p::Integer)` is deprecated. If your type relied on this definition,
     add a method such as `^(x::MyType, p::Integer) = Base.power_by_squaring(x, p)` ([#23332]).
 
-  * `wait` and `fetch` on `Task` now resemble the interface of `Future`
+  * `wait` and `fetch` on `Task` now resemble the interface of `Future`.
+
+  * `showcompact(io, x...)` has been deprecated in favor of
+    `show(IOContext(io, :compact => true), x...)` ([#26080]).
+    Use `sprint(showcompact, x...)` instead of `sprint(show, x..., context=:compact => true)`.
 
 Command-line option changes
 ---------------------------
@@ -1324,3 +1328,4 @@ Command-line option changes
 [#25745]: https://github.com/JuliaLang/julia/issues/25745
 [#25896]: https://github.com/JuliaLang/julia/issues/25896
 [#25998]: https://github.com/JuliaLang/julia/issues/25998
+[#26080]: https://github.com/JuliaLang/julia/issues/26080

base/Enums.jl

@@ -143,7 +143,7 @@ macro enum(T, syms...)
                 print(io, x)
             else
                 print(io, x, "::")
-                showcompact(io, typeof(x))
+                show(IOContext(io, :compact => true), typeof(x))
                 print(io, " = ", $basetype(x))
             end
         end

base/deprecated.jl

@@ -1400,6 +1400,10 @@ end
     Base.@deprecate log Base.log
 end
 
+@deprecate showcompact(x) show(IOContext(STDOUT, :compact => true), x)
+@deprecate showcompact(io, x) show(IOContext(io, :compact => true), x)
+@deprecate sprint(::typeof(showcompact), args...) sprint(show, args...; context=:compact => true)
+
 # END 0.7 deprecations
 
 # BEGIN 1.0 deprecations

base/exports.jl

@@ -624,7 +624,6 @@ export
     println,
     printstyled,
     show,
-    showcompact,
     showerror,
     sprint,
     summary,

base/irrationals.jl

@@ -153,7 +153,8 @@ big(::Type{<:AbstractIrrational}) = BigFloat
 
 # align along = for nice Array printing
 function alignment(io::IO, x::AbstractIrrational)
-    m = match(r"^(.*?)(=.*)$", sprint(showcompact, x, context=io, sizehint=0))
-    m === nothing ? (length(sprint(showcompact, x, context=io, sizehint=0)), 0) :
+    ctx = IOContext(io, :compact=>true)
+    m = match(r"^(.*?)(=.*)$", sprint(show, x, context=ctx, sizehint=0))
+    m === nothing ? (length(sprint(show, x, context=ctx, sizehint=0)), 0) :
     (length(m.captures[1]), length(m.captures[2]))
 end

base/show.jl

@@ -205,8 +205,8 @@ IOContext(io::IO, context::IO) = IOContext(unwrapcontext(io)[1], unwrapcontext(c
 Create an `IOContext` that wraps a given stream, adding the specified `key=>value` pairs to
 the properties of that stream (note that `io` can itself be an `IOContext`).
 
- - use `(key => value) in dict` to see if this particular combination is in the properties set
- - use `get(dict, key, default)` to retrieve the most recent value for a particular key
+ - use `(key => value) in io` to see if this particular combination is in the properties set
+ - use `get(io, key, default)` to retrieve the most recent value for a particular key
 
 The following properties are in common use:
 
@@ -1946,40 +1946,6 @@ function Base.showarg(io::IO, r::Iterators.Pairs{<:Any, <:Any, I, D}, toplevel)
     print(io, "Iterators.Pairs(::$D, ::$I)")
 end
 
-"""
-    showcompact(x)
-    showcompact(io::IO, x)
-
-Show a compact representation of a value to `io`. If `io` is not specified, the
-default is to print to [`STDOUT`](@ref).
-
-This is used for printing array elements without repeating type information (which would
-be redundant with that printed once for the whole array), and without line breaks inside
-the representation of an element.
-
-To offer a compact representation different from its standard one, a custom type should
-test `get(io, :compact, false)` in its normal [`show`](@ref) method.
-
-# Examples
-```jldoctest
-julia> A = [1. 2.; 3. 4]
-2×2 Array{Float64,2}:
- 1.0  2.0
- 3.0  4.0
-
-julia> showcompact(A)
-[1.0 2.0; 3.0 4.0]
-```
-"""
-showcompact(x) = showcompact(STDOUT, x)
-function showcompact(io::IO, x)
-    if get(io, :compact, false)
-        show(io, x)
-    else
-        show(IOContext(io, :compact => true), x)
-    end
-end
-
 
 # printing BitArrays
 

base/strings/io.jl

@@ -69,15 +69,21 @@ println(io::IO, xs...) = print(io, xs..., '\n')
 ## conversion of general objects to strings ##
 
 """
-    sprint(f::Function, args...)
+    sprint(f::Function, args...; context=nothing, sizehint::Integer=0)
 
 Call the given function with an I/O stream and the supplied extra arguments.
 Everything written to this I/O stream is returned as a string.
+`context` can be either an [`IOContext`](@ref) whose properties will be used,
+or a `Pair` specifying a property and its value. `sizehint` suggests the capacity
+of the buffer (in bytes).
 
 # Examples
 ```jldoctest
-julia> sprint(showcompact, 66.66666)
+julia> sprint(show, 66.66666; context=:compact => true)
 "66.6667"
+
+julia> sprint(showerror, BoundsError([1], 100))
+"BoundsError: attempt to access 1-element Array{Int64,1} at index [100]"
 ```
 """
 function sprint(f::Function, args...; context=nothing, sizehint::Integer=0)

doc/src/base/io-network.md

@@ -55,7 +55,6 @@ Base.IOContext(::IO, ::IOContext)
 
 ```@docs
 Base.show(::Any)
-Base.showcompact
 Base.summary
 Base.print
 Base.println

doc/src/manual/networking-and-streams.md

@@ -111,8 +111,9 @@ julia> print(STDOUT, 0x61)
 
 Sometimes IO output can benefit from the ability to pass contextual information into show methods.
 The [`IOContext`](@ref) object provides this framework for associating arbitrary metadata with an IO object.
-For example, [`showcompact`](@ref) adds a hinting parameter to the IO object that the invoked show method
-should print a shorter output (if applicable).
+For example, `:compact => true` adds a hinting parameter to the IO object that the invoked show method
+should print a shorter output (if applicable). See the [`IOContext`](@ref) documentation for a list
+of common properties.
 
 ## Working with Files
 

test/complex.jl

@@ -11,8 +11,8 @@ for T in (Int64, Float64)
     @test complex(Complex{T}) == Complex{T}
 end
 
-#showcompact
-@test sprint(showcompact, complex(1, 0)) == "1+0im"
+#show
+@test sprint(show, complex(1, 0), context=:compact => true) == "1+0im"
 @test sprint(show, complex(true, true)) == "Complex(true,true)"
 
 @testset "arithmetic" begin

test/dict.jl

@@ -350,7 +350,7 @@ end
 @testset "Issue #15739" begin # Compact REPL printouts of an `AbstractDict` use brackets when appropriate
     d = Dict((1=>2) => (3=>45), (3=>10) => (10=>11))
     buf = IOBuffer()
-    showcompact(buf, d)
+    show(IOContext(buf, :compact => true), d)
 
     # Check explicitly for the expected strings, since the CPU bitness effects
     # dictionary ordering.

test/float16.jl

@@ -108,7 +108,7 @@ end
     @test NaN16 != NaN16
     @test isequal(NaN16, NaN16)
     @test repr(NaN16) == "NaN16"
-    @test sprint(showcompact, NaN16) == "NaN"
+    @test sprint(show, NaN16, context=:compact => true) == "NaN"
 
     @test isinf(Inf16)
     @test isinf(-Inf16)
@@ -120,7 +120,7 @@ end
     @test -Inf16 < Inf16
     @test isequal(Inf16, Inf16)
     @test repr(Inf16) == "Inf16"
-    @test sprint(showcompact, Inf16) == "Inf"
+    @test sprint(show, Inf16, context=:compact => true) == "Inf"
 
     @test isnan(reinterpret(Float16,0x7c01))
     @test !isinf(reinterpret(Float16,0x7c01))

test/missing.jl

@@ -197,7 +197,7 @@ end
 
 @testset "printing" begin
     @test sprint(show, missing) == "missing"
-    @test sprint(showcompact, missing) == "missing"
+    @test sprint(show, missing, context=:compact => true) == "missing"
     @test sprint(show, [missing]) == "$Missing[missing]"
     @test sprint(show, [1 missing]) == "$(Union{Int, Missing})[1 missing]"
     b = IOBuffer()

test/mpfr.jl

@@ -895,7 +895,7 @@ end
         ends::String="",
         starts::String="")
         sx = sprint(show, x)
-        scx = sprint(showcompact, x)
+        scx = sprint(show, x, context=:compact => true)
         strx = string(x)
         @test sx == strx
         @test length(scx) < 20
@@ -915,8 +915,8 @@ end
     test_show_bigfloat(big"-2.3457645687563543266576889678956787e-10000", starts="-2.345", ends="e-10000")
 
     for to_string in [string,
-        x->sprint(show, x),
-        x->sprint(showcompact,x)]
+                      x->sprint(show, x),
+                      x->sprint(show, x, context=:compact => true)]
         @test to_string(big"0.0") == "0.0"
         @test to_string(big"-0.0") == "-0.0"
         @test to_string(big"1.0") == "1.0"

test/numbers.jl

@@ -410,14 +410,14 @@ end
     @test repr(-NaN) == "NaN"
     @test repr(Float64(pi)) == "3.141592653589793"
     # issue 6608
-    @test sprint(showcompact, 666666.6) == "6.66667e5"
-    @test sprint(showcompact, 666666.049) == "666666.0"
-    @test sprint(showcompact, 666665.951) == "666666.0"
-    @test sprint(showcompact, 66.66666) == "66.6667"
-    @test sprint(showcompact, -666666.6) == "-6.66667e5"
-    @test sprint(showcompact, -666666.049) == "-666666.0"
-    @test sprint(showcompact, -666665.951) == "-666666.0"
-    @test sprint(showcompact, -66.66666) == "-66.6667"
+    @test sprint(show, 666666.6, context=:compact => true) == "6.66667e5"
+    @test sprint(show, 666666.049, context=:compact => true) == "666666.0"
+    @test sprint(show, 666665.951, context=:compact => true) == "666666.0"
+    @test sprint(show, 66.66666, context=:compact => true) == "66.6667"
+    @test sprint(show, -666666.6, context=:compact => true) == "-6.66667e5"
+    @test sprint(show, -666666.049, context=:compact => true) == "-666666.0"
+    @test sprint(show, -666665.951, context=:compact => true) == "-666666.0"
+    @test sprint(show, -66.66666, context=:compact => true) == "-66.6667"
 
     @test repr(1.0f0) == "1.0f0"
     @test repr(-1.0f0) == "-1.0f0"
@@ -2580,7 +2580,7 @@ end
                             (-T(Inf), "-Inf")]
                 @assert x isa T
                 @test string(x) == sx
-                @test sprint(io -> show(IOContext(io, :compact => true), x)) == sx
+                @test sprint(show, x, context=:compact => true) == sx
                 @test sprint(print, x) == sx
             end
         end

test/show.jl

@@ -738,16 +738,6 @@ end
 @test !contains(repr(fill(1.,10,10)), "\u2026")
 @test contains(sprint((io, x) -> show(IOContext(io, :limit => true), x), fill(1.,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)
-    @test String(take!(io)) == "[1, 2]"
-end
-
 let io = IOBuffer()
     ioc = IOContext(io, :limit => true)
     @test sprint(show, ioc) == "IOContext($(sprint(show, ioc.io)))"