tweak printing of underflow

base/essentials.jl

@@ -403,11 +403,11 @@ For example,
 # Examples
 ```jldoctest
 julia> reinterpret(Float32, UInt32(7))
-1.0f-44
+1f-44
 
 julia> reinterpret(Float32, UInt32[1 2 3 4 5])
 1×5 reinterpret(Float32, ::Array{UInt32,2}):
- 1.0f-45 3.0f-45 4.0f-45 6.0f-45 7.0f-45
+ 1f-45 3f-45 4f-45 6f-45 7f-45
 ```
 """
 reinterpret(::Type{T}, x) where {T} = bitcast(T, x)

base/ryu/Ryu.jl

@@ -27,7 +27,7 @@ Note the 2nd method allows passing in a byte buffer and position directly; calle
 Various options for the output format include:
  * `plus`: for positive `x`, prefix decimal string with a `'+'` character
  * `space`: for positive `x`, prefix decimal string with a `' '` character; overridden if `plus=true`
- * `hash`: whether the decimal point should be written, even if no additional digits are needed for precision
+ * `hash`: whether the decimal point should be written, even if no additional digits are needed for precision. Default is `nothing`, which will only force printing if no exponent is used.
  * `precision`: minimum number of digits to be included in the decimal string; extra `'0'` characters will be added for padding if necessary
  * `expchar`: character to use exponent component in scientific notation
  * `padexp`: whether two digits should always be written, even for single-digit exponents (e.g. `e+1` becomes `e+01`)
@@ -38,7 +38,7 @@ Various options for the output format include:
 function writeshortest(x::T,
  plus::Bool=false,
  space::Bool=false,
- hash::Bool=true,
+ hash::Union{Bool,Nothing}=nothing,
  precision::Integer=-1,
  expchar::UInt8=UInt8('e'),
  padexp::Bool=false,
@@ -112,7 +112,7 @@ function Base.show(io::IO, x::T, forceuntyped::Bool=false) where {T <: Base.IEEE
  compact = get(io, :compact, false)
  buf = Base.StringVector(neededdigits(T))
  typed = !forceuntyped && !compact && get(io, :typeinfo, Any) != typeof(x)
- pos = writeshortest(buf, 1, x, false, false, true, -1,
+ pos = writeshortest(buf, 1, x, false, false, nothing, -1,
  x isa Float32 ? UInt8('f') : UInt8('e'), false, UInt8('.'), typed, compact)
  write(io, resize!(buf, pos - 1))
  return

base/ryu/shortest.jl

@@ -226,7 +226,7 @@ end
 
 
 @inline function writeshortest(buf::Vector{UInt8}, pos, x::T,
- plus=false, space=false, hash=true,
+ plus=false, space=false, hash=nothing,
  precision=-1, expchar=UInt8('e'), padexp=false, decchar=UInt8('.'),
  typed=false, compact=false) where {T}
  @assert 0 < pos <= length(buf)
@@ -245,7 +245,7 @@ end
  end
  buf[pos] = UInt8('0')
  pos += 1
- if hash
+ if hash === nothing || hash
  buf[pos] = decchar
  pos += 1
  end
@@ -332,6 +332,9 @@ end
  pt = nexp + olength
  if -4 < pt <= (precision == -1 ? (T == Float16 ? 3 : 6) : precision)
  exp_form = false
+ if hash === nothing
+ hash = true
+ end
  if pt <= 0
  buf[pos] = UInt8('0')
  pos += 1
@@ -347,6 +350,9 @@ end
  # nothing to do at this point
  end
  else
+ if hash === nothing
+ hash = false
+ end
  pos += 1
  end
  i = 0

doc/src/manual/integers-and-floating-point-numbers.md

@@ -269,7 +269,7 @@ julia> -1.23
 -1.23
 
 julia> 1e10
-1.0e10
+1e10
 
 julia> 2.5e-4
 0.00025
@@ -331,7 +331,7 @@ The underscore `_` can be used as digit separator:
 
 ```jldoctest
 julia> 10_000, 0.000_000_005, 0xdead_beef, 0b1011_0010
-(10000, 5.0e-9, 0xdeadbeef, 0xb2)
+(10000, 5e-9, 0xdeadbeef, 0xb2)
 ```
 
 ### Floating-point zero
@@ -454,7 +454,7 @@ julia> eps(1e-27)
 1.793662034335766e-43
 
 julia> eps(0.0)
-5.0e-324
+5e-324
 ```
 
 The distance between two adjacent representable floating-point numbers is not constant, but is

doc/src/manual/variables.md

@@ -46,7 +46,7 @@ Unicode names (in UTF-8 encoding) are allowed:
 
 ```jldoctest
 julia> δ = 0.00001
-1.0e-5
+1e-5
 
 julia> 안녕하세요 = "Hello"
 "Hello"

test/ryu.jl

@@ -23,7 +23,7 @@ end
 
 @testset "MinAndMax" begin
  @test "1.7976931348623157e308" == Ryu.writeshortest(Core.bitcast(Float64, 0x7fefffffffffffff))
- @test "5.0e-324" == Ryu.writeshortest(Core.bitcast(Float64, Int64(1)))
+ @test "5e-324" == Ryu.writeshortest(Core.bitcast(Float64, Int64(1)))
 end
 
 @testset "LotsOfTrailingZeros" begin
@@ -158,16 +158,16 @@ end
  @test "1000.0" == Ryu.writeshortest(1.0e+3)
  @test "10000.0" == Ryu.writeshortest(1.0e+4)
  @test "100000.0" == Ryu.writeshortest(1.0e+5)
- @test "1.0e6" == Ryu.writeshortest(1.0e+6)
- @test "1.0e7" == Ryu.writeshortest(1.0e+7)
- @test "1.0e8" == Ryu.writeshortest(1.0e+8)
- @test "1.0e9" == Ryu.writeshortest(1.0e+9)
- @test "1.0e10" == Ryu.writeshortest(1.0e+10)
- @test "1.0e11" == Ryu.writeshortest(1.0e+11)
- @test "1.0e12" == Ryu.writeshortest(1.0e+12)
- @test "1.0e13" == Ryu.writeshortest(1.0e+13)
- @test "1.0e14" == Ryu.writeshortest(1.0e+14)
- @test "1.0e15" == Ryu.writeshortest(1.0e+15)
+ @test "1e6" == Ryu.writeshortest(1.0e+6)
+ @test "1e7" == Ryu.writeshortest(1.0e+7)
+ @test "1e8" == Ryu.writeshortest(1.0e+8)
+ @test "1e9" == Ryu.writeshortest(1.0e+9)
+ @test "1e10" == Ryu.writeshortest(1.0e+10)
+ @test "1e11" == Ryu.writeshortest(1.0e+11)
+ @test "1e12" == Ryu.writeshortest(1.0e+12)
+ @test "1e13" == Ryu.writeshortest(1.0e+13)
+ @test "1e14" == Ryu.writeshortest(1.0e+14)
+ @test "1e15" == Ryu.writeshortest(1.0e+15)
 
  # 10^15 + 10^i
  @test "1.000000000000001e15" == Ryu.writeshortest(1.0e+15 + 1.0e+0)
@@ -240,14 +240,14 @@ end
 
 @testset "MinAndMax" begin
  @test "3.4028235e38" == Ryu.writeshortest(Core.bitcast(Float32, 0x7f7fffff))
- @test "1.0e-45" == Ryu.writeshortest(Core.bitcast(Float32, Int32(1)))
+ @test "1e-45" == Ryu.writeshortest(Core.bitcast(Float32, Int32(1)))
 end
 
 # Check that we return the exact boundary if it is the shortest
 # representation, but only if the original floating point number is even.
 @testset "BoundaryRoundeven" begin
  @test "3.355445e7" == Ryu.writeshortest(3.355445f7)
- @test "9.0e9" == Ryu.writeshortest(8.999999f9)
+ @test "9e9" == Ryu.writeshortest(8.999999f9)
  @test "3.436672e10" == Ryu.writeshortest(3.4366717f10)
 end
 
@@ -284,15 +284,15 @@ end
  @test "7.038531e-26" == Ryu.writeshortest(7.0385309f-26)
  @test "9.223404e17" == Ryu.writeshortest(9.2234038f17)
  @test "6.710887e7" == Ryu.writeshortest(6.7108872f7)
- @test "1.0e-44" == Ryu.writeshortest(1.0f-44)
+ @test "1e-44" == Ryu.writeshortest(1.0f-44)
  @test "2.816025e14" == Ryu.writeshortest(2.816025f14)
  @test "9.223372e18" == Ryu.writeshortest(9.223372f18)
  @test "1.5846086e29" == Ryu.writeshortest(1.5846085f29)
  @test "1.1811161e19" == Ryu.writeshortest(1.1811161f19)
  @test "5.368709e18" == Ryu.writeshortest(5.368709f18)
  @test "4.6143166e18" == Ryu.writeshortest(4.6143165f18)
  @test "0.007812537" == Ryu.writeshortest(0.007812537f0)
- @test "1.0e-45" == Ryu.writeshortest(1.4f-45)
+ @test "1e-45" == Ryu.writeshortest(1.4f-45)
  @test "1.18697725e20" == Ryu.writeshortest(1.18697724f20)
  @test "1.00014165e-36" == Ryu.writeshortest(1.00014165f-36)
  @test "200.0" == Ryu.writeshortest(200f0)
@@ -760,9 +760,9 @@ end # exp
  @test stringcompact(0.025621074) == "0.0256211"
 
  # subnormals
- @test stringcompact(eps(0.0)) == "5.0e-324"
- @test stringcompact(eps(0f0)) == "1.0f-45"
- @test stringcompact(eps(Float16(0.0))) == "6.0e-8"
+ @test stringcompact(eps(0.0)) == "5e-324"
+ @test stringcompact(eps(0f0)) == "1f-45"
+ @test stringcompact(eps(Float16(0.0))) == "6e-8"
 end
 
 end # Ryu