Checks if the {} are balanced.

balanced.rb

test_data = ["{dsfgsdf}", "{asdf}, {sdfsdf}", "{{dfgd}, {sadf}}", "sdfd}{", "{asdfsad}, {sdfs}}", "{{asdf},{sdfsdf}"]

test_data.each { |s|
    res = s.split(//).reduce(0) { |sum, c|
        break sum if sum < 0
        sum +=1 if c == "{"
        sum -=1 if c == "}"
        sum
    }
    puts s + " is #{res != 0 ? "no ":""}good!"
}

Output:

{dsfgsdf} is good!
{asdf}, {sdfsdf} is good!
{{dfgd}, {sadf}} is good!
sdfd}{ is no good!
{asdfsad}, {sdfs}} is no good!
{{asdf},{sdfsdf} is no good!

JSON strings can contain {}.

`test_data = ["{dsfgsdf}", "{asdf}, {sdfsdf}", "{{dfgd}, {sadf}}", "sdfd}{", "{asdfsad}, {sdfs}}", "{{asdf},{sdfsdf}", '{"test{{{"}, {"{{{fest"}']

test_data.each { |s|
instring = false;
res = s.split(//).reduce(0) { |sum, c|
break sum if sum < 0
instring = !instring if c == '"'
if !instring
sum +=1 if c == "{"
sum -=1 if c == "}"
end
sum
}
puts s + " is #{res != 0 ? "no ":""}good!"
}
`