Throw an exception instead of the character when the scanner finds an…

… invalid character. (#233)

src/scanner.jl

@@ -270,8 +270,9 @@ function fetch_more_tokens(stream::TokenStream)
     elseif check_plain(stream)
         fetch_plain(stream)
     else
-        # TODO: Throw a meaningful exception.
-        throw(c)
+        throw(ScannerError(nothing, nothing,
+                           "while scanning for the next token, found character '$c' that cannot start any token",
+                           get_mark(stream)))
     end
 end
 

test/runtests.jl

@@ -349,6 +349,11 @@ end
     dicttype=() -> 3.0 # wrong type
 )
 
+@test_throws YAML.ScannerError YAML.load("x: %")
+if VERSION >= v"1.8"
+    @test_throws "found character '%' that cannot start any token" YAML.load("x: %")
+end
+
 # issue 81
 dict_content = ["key1" => [Dict("subkey1" => "subvalue1", "subkey2" => "subvalue2"), Dict()], "key2" => "value2"]
 order_one = OrderedDict(dict_content...)