add tuple type printing with Vararg, and port to static_show (Julia…

…Lang#44970)

base/show.jl

@@ -993,19 +993,31 @@ function show_datatype(io::IO, x::DataType, wheres::Vector{TypeVar}=TypeVar[])
  istuple = x.name === Tuple.name
  n = length(parameters)
 
- # Print homogeneous tuples with more than 3 elements compactly as NTuple{N, T}
+ # Print tuple types with homogeneous tails longer than max_n compactly using `NTuple` or `Vararg`
+ max_n = 3
  if istuple
- if n > 3 && all(@nospecialize(i) -> (parameters[1] === i), parameters)
+ taillen = 1
+ for i in (n-1):-1:1
+ if parameters[i] === parameters[n]
+ taillen += 1
+ else
+ break
+ end
+ end
+ if n == taillen > max_n
  print(io, "NTuple{", n, ", ")
  show(io, parameters[1])
  print(io, "}")
  else
  print(io, "Tuple{")
- # join(io, params, ", ") params but `show` it
- first = true
- for param in parameters
- first ? (first = false) : print(io, ", ")
- show(io, param)
+ for i = 1:(taillen > max_n ? n-taillen : n)
+ i > 1 && print(io, ", ")
+ show(io, parameters[i])
+ end
+ if taillen > max_n
+ print(io, ", Vararg{")
+ show(io, parameters[n])
+ print(io, ", ", taillen, "}")
  end
  print(io, "}")
  end

src/rtutils.c

@@ -785,6 +785,37 @@ static size_t jl_static_show_x_(JL_STREAM *out, jl_value_t *v, jl_datatype_t *vt
  jl_sym_t *sym = globfunc ? globname : dv->name->name;
  char *sn = jl_symbol_name(sym);
  size_t quote = 0;
+ if (dv->name == jl_tuple_typename) {
+ if (dv == jl_tuple_type)
+ return jl_printf(out, "Tuple");
+ int taillen = 1, tlen = jl_nparams(dv), i;
+ for (i = tlen-2; i >= 0; i--) {
+ if (jl_tparam(dv, i) == jl_tparam(dv, tlen-1))
+ taillen++;
+ else
+ break;
+ }
+ if (taillen == tlen && taillen > 3) {
+ n += jl_printf(out, "NTuple{%d, ", tlen);
+ n += jl_static_show_x(out, jl_tparam0(dv), depth);
+ n += jl_printf(out, "}");
+ }
+ else {
+ n += jl_printf(out, "Tuple{");
+ for (i = 0; i < (taillen > 3 ? tlen-taillen : tlen); i++) {
+ if (i > 0)
+ n += jl_printf(out, ", ");
+ n += jl_static_show_x(out, jl_tparam(dv, i), depth);
+ }
+ if (taillen > 3) {
+ n += jl_printf(out, ", Vararg{");
+ n += jl_static_show_x(out, jl_tparam(dv, tlen-1), depth);
+ n += jl_printf(out, ", %d}", taillen);
+ }
+ n += jl_printf(out, "}");
+ }
+ return n;
+ }
  if (globfunc) {
  n += jl_printf(out, "typeof(");
  }
@@ -804,9 +835,7 @@ static size_t jl_static_show_x_(JL_STREAM *out, jl_value_t *v, jl_datatype_t *vt
  n += jl_printf(out, ")");
  }
  }
- if (dv->parameters && (jl_value_t*)dv != dv->name->wrapper &&
- (jl_has_free_typevars(v) ||
- (jl_value_t*)dv != (jl_value_t*)jl_tuple_type)) {
+ if (dv->parameters && (jl_value_t*)dv != dv->name->wrapper) {
  size_t j, tlen = jl_nparams(dv);
  if (tlen > 0) {
  n += jl_printf(out, "{");
@@ -818,9 +847,6 @@ static size_t jl_static_show_x_(JL_STREAM *out, jl_value_t *v, jl_datatype_t *vt
  }
  n += jl_printf(out, "}");
  }
- else if (dv->name == jl_tuple_typename) {
- n += jl_printf(out, "{}");
- }
  }
  }
  else if (vt == jl_intrinsic_type) {

test/show.jl

@@ -1338,6 +1338,8 @@ test_repr("(:).a")
 @test repr(NTuple{7,Int64}) == "NTuple{7, Int64}"
 @test repr(Tuple{Float64, Float64, Float64, Float64}) == "NTuple{4, Float64}"
 @test repr(Tuple{Float32, Float32, Float32}) == "Tuple{Float32, Float32, Float32}"
+@test repr(Tuple{String, Int64, Int64, Int64}) == "Tuple{String, Int64, Int64, Int64}"
+@test repr(Tuple{String, Int64, Int64, Int64, Int64}) == "Tuple{String, Vararg{Int64, 4}}"
 
 @testset "issue #42931" begin
  @test repr(NTuple{4, :A}) == "NTuple{4, :A}"