Merge pull request #237 from dalum/master

Fix issue with special keys that require quoting in mappings

src/writer.jl

@@ -73,9 +73,14 @@ end
 function _print(io::IO, pair::Pair, level::Int=0, ignore_level::Bool=false)
     key = if pair[1] === nothing
         "null" # this is what the YAML parser interprets as 'nothing'
+    elseif pair[1] isa AbstractString && (
+        occursin('#', pair[1]) || first(pair[1]) in "{}[]&*?|-<>=!%@:`,\"'"
+    )
+        string("\"", escape_string(pair[1]), "\"") # special keys that require quoting
     else
         string(pair[1]) # any useful case
     end
+
     print(io, _indent(key * ":", level, ignore_level)) # print the key
     if (pair[2] isa AbstractDict || pair[2] isa AbstractVector) && !isempty(pair[2])
         print(io, "\n") # a line break is needed before a recursive structure

test/runtests.jl

@@ -473,4 +473,19 @@ end
     @test collect(YAML.load_all(input)) == expected
 end
 
+# issue #236 - special string keys that require enclosure in quotes
+@testset "issue #236" begin
+    for char in "{}[]&*?#|-<>=!%@:`,\"'"
+        test_case_1 = Dict(string(char) => 0.0)
+        test_case_2 = Dict(string(char, "abcd") => 0.0)
+        test_case_3 = Dict(string("abcd", char) => 0.0)
+        test_case_4 = Dict(string("abcd", char, "efgh") => 0.0)
+
+        @test YAML.load(YAML.yaml(test_case_1)) == test_case_1
+        @test YAML.load(YAML.yaml(test_case_2)) == test_case_2
+        @test YAML.load(YAML.yaml(test_case_3)) == test_case_3
+        @test YAML.load(YAML.yaml(test_case_4)) == test_case_4
+    end
+end
+
 end  # module