fix #11

src/io.jl

@@ -174,6 +174,7 @@ function Base.IOContext(io::GarishIO, KVs::Pair...)
     )
 end
 
+Base.show_circular(io::GarishIO, x) = Base.show_circular(io.bland_io, x)
 Base.displaysize(io::GarishIO) = io.displaysize
 Base.in(key_value::Pair, io::GarishIO) = in(key_value, IOContext(io).dict, ===)
 Base.haskey(io::GarishIO, key) = haskey(IOContext(io).dict, key)

src/pprint.jl

@@ -74,7 +74,7 @@ pprint(io::GarishIO, ::MIME"text/plain", @specialize(x::Type)) = print_token(io,
 # Struct
 function pprint(io::GarishIO, mime::MIME, @nospecialize(x))
     if fallback_to_default_show(io, x) && isstructtype(typeof(x))
-        return pprint_struct(io, mime, x)
+        pprint_struct(io, mime, x)
     elseif io.state.level > 0 # print show inside
         show_text_within(io, mime, x)
     else # fallback to show unless it is a struct type

src/struct.jl

@@ -25,58 +25,63 @@ end
 Print `x` as a struct type with mime type `MIME"text/plain"`.
 """
 function pprint_struct(io::GarishIO, mime::MIME"text/plain", @nospecialize(x))
-    t = typeof(x)
-    isstructtype(t) || throw(ArgumentError("expect a struct type, got $t"))
-    pprint_struct_type(io, mime, t); print(io.bland_io, "(")
+    if !Base.show_circular(io, x)
+        recur_io = IOContext(io.bland_io, :SHOWN_SET => x)
 
-    nf = nfields(x)::Int
-    nf == 0 && return print(io.bland_io, ")")
+        t = typeof(x)
+        isstructtype(t) || throw(ArgumentError("expect a struct type, got $t"))
+        pprint_struct_type(io, mime, t)
+        print(io.bland_io, "(")
 
-    io.compact || println(io.bland_io)
+        nf = nfields(x)::Int
+        nf == 0 && return print(io.bland_io, ")")
 
-    # findout fields to print
-    fields_to_print = Int[]
-    for i in 1:nf
-        f = fieldname(t, i)
-        value = getfield(x, i)
-        if !io.include_defaults && is_option(x) && value == field_default(t, f)
-        else
-            push!(fields_to_print, i)
-        end
-    end
+        io.compact || println(io.bland_io)
 
-    within_nextlevel(io) do
-        for i in fields_to_print
+        # findout fields to print
+        fields_to_print = Int[]
+        for i = 1:nf
             f = fieldname(t, i)
             value = getfield(x, i)
-            print_indent(io)
-            print_token(io, :fieldname, f)
-            if io.compact
-                print(io.bland_io, "=")
+            if !io.include_defaults && is_option(x) && value == field_default(t, f)
             else
-                print(io.bland_io, " = ")
-                io.state.offset = 3 + length(string(f))
+                push!(fields_to_print, i)
             end
+        end
 
-            if !isdefined(x, f) # print undef as comment color
-                pprint(io, undef)
-            else
-                new_io = GarishIO(io; limit=true)
-                pprint_field(new_io, mime, value)
-            end
+        within_nextlevel(io) do
+            for i in fields_to_print
+                f = fieldname(t, i)
+                value = getfield(x, i)
+                print_indent(io)
+                print_token(io, :fieldname, f)
+                if io.compact
+                    print(io.bland_io, "=")
+                else
+                    print(io.bland_io, " = ")
+                    io.state.offset = 3 + length(string(f))
+                end
 
-            if !io.compact || i != last(fields_to_print)
-                print(io.bland_io, ", ")
-            end
+                if !isdefined(x, f) # print undef as comment color
+                    pprint(io, undef)
+                else
+                    new_io = GarishIO(recur_io, io; limit = true)
+                    pprint_field(new_io, mime, value)
+                end
 
-            if i != last(fields_to_print)
-                io.compact || println(io.bland_io)
+                if !io.compact || i != last(fields_to_print)
+                    print(io.bland_io, ", ")
+                end
+
+                if i != last(fields_to_print)
+                    io.compact || println(io.bland_io)
+                end
             end
         end
+        io.compact || println(io.bland_io)
+        print_indent(io)
+        print(io.bland_io, ")")
     end
-    io.compact || println(io.bland_io)
-    print_indent(io)
-    print(io.bland_io, ")")
 end
 
 function pprint_struct_type(io::GarishIO, mime::MIME"text/plain", @nospecialize(x))
@@ -121,11 +126,15 @@ end
 pprint_field(io::GarishIO, x) = pprint_field(io, MIME"text/plain"(), x)
 
 function pprint_field(io::GarishIO, mime::MIME"text/plain", x)
-    upperlevel_type = io.state.type
-    upperlevel_noindent_in_first_line = io.state.noindent_in_first_line
-    io.state.type = StructField
-    io.state.noindent_in_first_line = true
-    pprint(io, mime, x)
-    io.state.noindent_in_first_line = upperlevel_noindent_in_first_line
-    io.state.type = upperlevel_type
+    if !Base.show_circular(io, x)
+        recur_io = IOContext(io, :SHOWN_SET => x)
+
+        upperlevel_type = io.state.type
+        upperlevel_noindent_in_first_line = io.state.noindent_in_first_line
+        io.state.type = StructField
+        io.state.noindent_in_first_line = true
+        pprint(GarishIO(recur_io, io), mime, x)
+        io.state.noindent_in_first_line = upperlevel_noindent_in_first_line
+        io.state.type = upperlevel_type
+    end
 end

test/basic.jl

@@ -27,6 +27,10 @@ struct T5{T}
     x::T
 end
 
+mutable struct T6
+    x::Any
+end
+
 struct TTTTTTTTTTTTTTTTTTTT{A,B}
     x::A
     y::B
@@ -62,6 +66,14 @@ pprint(T5(Dict("a"=>T4(T5([1, 2, 3]), T5([1, 2, 3])), "b"=>2im)))
 
 pprint(T5(Dict("a"=>(1, 2, 3), "b"=>Any)))
 
+recur_struct = T6(nothing)
+recur_struct.x = recur_struct
+pprint(recur_struct)
+
+recur_struct_list = T6([])
+push!(recur_struct_list.x, T5(recur_struct_list))
+pprint(recur_struct_list)
+
 a = TTTTTTTTTTTTTTTTTTTT(1, 2)
 b = TTTTTTTTTTTTTTTTTTTT(a, a)
 c = TTTTTTTTTTTTTTTTTTTT(b, b)