Fix some edge cases in string and show for Arb and Acb

The matrix `Arb[1 1]` is now displayed as

1×2 Matrix{Arb}:
 1.0  1.0

instead of as

1×2 Matrix{Arb}:
 1.00{…72 digits…}  1.00{…72 digits…}

src/show.jl

@@ -6,14 +6,14 @@ function _remove_trailing_zeros(str::AbstractString)
             # Numbers on the form xxx.yyy0ezzz
             mantissa, exponent = split(str, 'e', limit = 2)
             mantissa = rstrip(mantissa, '0')
-            if endswith(mantissa, '.')
+            if endswith(mantissa, '.') || endswith(mantissa, '}')
                 mantissa *= '0'
             end
             str = mantissa * 'e' * exponent
         else
             # Numbers on the form xxx.yyy0
             str = rstrip(str, '0')
-            if endswith(str, '.')
+            if endswith(str, '.') || endswith(str, '}')
                 str *= '0'
             end
         end
@@ -129,7 +129,20 @@ end
 
 function Base.show(io::IO, x::Union{ArbOrRef,AcbOrRef})
     if Base.get(io, :compact, false) && rel_accuracy_bits(x) > 48
-        print(io, string(x, condense = 2, unicode = true))
+        str = string(x, condense = 2, unicode = true)
+        if isexact(x)
+            # For exact values the shortest output is in some cases
+            # not given by condensing the decimal digits, but by
+            # removing trailing zeros. We try both options and take
+            # the shortest.
+
+            str_alt = string(x)
+
+            if length(str_alt) < length(str)
+                str = str_alt
+            end
+        end
+        print(io, str)
     else
         print(io, string(x))
     end

test/show.jl

@@ -30,6 +30,7 @@
               "1.000000000000000000"
         @test string(Arb(1), digits = 2, remove_trailing_zeros = false) == "1.0"
         @test string(Arb(1), digits = 12, remove_trailing_zeros = false) == "1.00000000000"
+        @test string(Arb(1), condense = 2) == "1.00{...72 digits...}0"
         @test string(Arb(10)^100) == "1.0e+100"
         @test string(Arb(10)^100, remove_trailing_zeros = false) ==
               "1.0000000000000000000000000000000000000000000000000000000000000000000000000000e+100"
@@ -90,10 +91,20 @@
     @testset "show" begin
         @test repr(Mag(1), context = IOContext(stdout, :compact => true)) == "1.0"
         @test repr(Arf(1), context = IOContext(stdout, :compact => true)) == "1.0"
+        @test repr(Arb(1), context = IOContext(stdout, :compact => true)) == "1.0"
+        @test repr(Acb(1, 1), context = IOContext(stdout, :compact => true)) ==
+              "1.0 + 1.0im"
+
         @test repr(Arb(π), context = IOContext(stdout, :compact => true)) ==
               "[3.14{…72 digits…}62 ± 1.93e-77]"
         @test repr(Acb(π, ℯ), context = IOContext(stdout, :compact => true)) ==
               "[3.14{…72 digits…}62 ± 1.93e-77] + [2.71{…72 digits…}35 ± 5.46e-77]im"
+        @test repr(Arb(Float64(π)), context = IOContext(stdout, :compact => true)) ==
+              "3.14{…72 digits…}0"
+        @test repr(
+            Acb(Float64(π), Float64(ℯ)),
+            context = IOContext(stdout, :compact => true),
+        ) == "3.14{…72 digits…}0 + 2.71{…72 digits…}0im"
 
         prec = 32