Merge pull request JuliaLang#10657 from JuliaLang/mb/recursiveshowdict

Display recursive dictionaries correctly

base/dict.jl

@@ -18,27 +18,7 @@ function summary(t::Associative)
  string(typeof(t), " with ", n, (n==1 ? " entry" : " entries"))
 end
 
-function show{K,V}(io::IO, t::Associative{K,V})
- if isempty(t)
- print(io, typeof(t), "()")
- else
- if isleaftype(K) && isleaftype(V)
- print(io, typeof(t).name)
- else
- print(io, typeof(t))
- end
- print(io, '(')
- first = true
- for (k, v) in t
- first || print(io, ',')
- first = false
- show(io, k)
- print(io, "=>")
- show(io, v)
- end
- print(io, ')')
- end
-end
+show{K,V}(io::IO, t::Associative{K,V}) = showdict(io, t; compact = true)
 
 function _truncate_at_width_or_chars(str, width, chars="", truncmark="…")
  truncwidth = strwidth(truncmark)
@@ -64,48 +44,87 @@ function _truncate_at_width_or_chars(str, width, chars="", truncmark="…")
 end
 
 showdict(t::Associative; kw...) = showdict(STDOUT, t; kw...)
-function showdict{K,V}(io::IO, t::Associative{K,V}; limit::Bool = false,
+function showdict{K,V}(io::IO, t::Associative{K,V}; limit::Bool = false, compact = false,
  sz=(s = tty_size(); (s[1]-3, s[2])))
- rows, cols = sz
- print(io, summary(t))
- isempty(t) && return
- print(io, ":")
-
- if limit
- rows < 2 && (print(io, " …"); return)
- cols < 12 && (cols = 12) # Minimum widths of 2 for key, 4 for value
- cols -= 6 # Subtract the widths of prefix " " separator " => "
- rows -= 2 # Subtract the summary and final ⋮ continuation lines
-
- # determine max key width to align the output, caching the strings
- ks = Array(AbstractString, min(rows, length(t)))
- keylen = 0
- for (i, k) in enumerate(keys(t))
- i > rows && break
- ks[i] = sprint(show, k)
- keylen = clamp(length(ks[i]), keylen, div(cols, 3))
+ shown_set = get(task_local_storage(), :SHOWNSET, nothing)
+ if shown_set == nothing
+ shown_set = ObjectIdDict()
+ task_local_storage(:SHOWNSET, shown_set)
+ end
+ t in keys(shown_set) && (print(io, "#= circular reference =#"); return)
+
+ try
+ shown_set[t] = true
+ if compact
+ # show in a Julia-syntax-like form: Dict(k=>v, ...)
+ if isempty(t)
+ print(io, typeof(t), "()")
+ else
+ if isleaftype(K) && isleaftype(V)
+ print(io, typeof(t).name)
+ else
+ print(io, typeof(t))
+ end
+ print(io, '(')
+ first = true
+ n = 0
+ for (k, v) in t
+ first || print(io, ',')
+ first = false
+ show(io, k)
+ print(io, "=>")
+ show(io, v)
+ n+=1
+ limit && n >= 10 && (print(io, "…"); break)
+ end
+ print(io, ')')
+ end
+ return
  end
- end
-
- for (i, (k, v)) in enumerate(t)
- print(io, "\n ")
- limit && i > rows && (print(io, rpad("⋮", keylen), " => ⋮"); break)
 
+ # Otherwise show more descriptively, with one line per key/value pair
+ rows, cols = sz
+ print(io, summary(t))
+ isempty(t) && return
+ print(io, ":")
  if limit
- key = rpad(_truncate_at_width_or_chars(ks[i], keylen, "\r\n"), keylen)
- else
- key = sprint(show, k)
+ rows < 2 && (print(io, " …"); return)
+ cols < 12 && (cols = 12) # Minimum widths of 2 for key, 4 for value
+ cols -= 6 # Subtract the widths of prefix " " separator " => "
+ rows -= 2 # Subtract the summary and final ⋮ continuation lines
+
+ # determine max key width to align the output, caching the strings
+ ks = Array(AbstractString, min(rows, length(t)))
+ keylen = 0
+ for (i, k) in enumerate(keys(t))
+ i > rows && break
+ ks[i] = sprint(show, k)
+ keylen = clamp(length(ks[i]), keylen, div(cols, 3))
+ end
  end
- print(io, key)
- print(io, " => ")
 
- if limit
- val = with_output_limit(()->sprint(show, v))
- val = _truncate_at_width_or_chars(val, cols - keylen, "\r\n")
- print(io, val)
- else
- show(io, v)
+ for (i, (k, v)) in enumerate(t)
+ print(io, "\n ")
+ limit && i > rows && (print(io, rpad("⋮", keylen), " => ⋮"); break)
+
+ if limit
+ key = rpad(_truncate_at_width_or_chars(ks[i], keylen, "\r\n"), keylen)
+ else
+ key = sprint(show, k)
+ end
+ print(io, key)
+ print(io, " => ")
+
+ if limit
+ val = with_output_limit(()->sprint(show, v))
+ val = _truncate_at_width_or_chars(val, cols - keylen, "\r\n")
+ print(io, val)
+ else
+ show(io, v)
+ end
  end
+ finally
+ delete!(shown_set, t)
  end
 end
 

test/dict.jl

@@ -313,3 +313,15 @@ let
  @test d['f'] == 6
  @test length(d) == 6
 end
+
+# issue #10647
+let
+ a = ObjectIdDict()
+ a[1] = a
+ a[a] = 2
+ type T10647{T}; x::T; end
+ a[3] = T10647(a)
+ show(IOBuffer(), a)
+ Base.showdict(IOBuffer(), a)
+ Base.showdict(IOBuffer(), a; limit=true)
+end