Current culture won't work because C# expects literals in invariant culture.
Use 3.14.ToString(CultureInfo.InvariantCulture);

This issue isn't low impact on any system using a decimal point other than '.'. It renders the shader part of bling unusable. I like the shader part alot, I want to use it.

Anyway, I created a small patch that seems to work for me. I don't know bling at all so I might missed some cases.

Current (as of 35476)
Shaders.cs:

    Func<int, string> EToString = (idx) => {
      var e = arity.Access(constant.Value, idx);
      if (arity.TypeOfK == typeof(bool)) return ((bool)e) ? "1" : "0";
      else return e.ToString();
    };

Patched:

    Func<int, string> EToString = (idx) => {
      var e = arity.Access(constant.Value, idx);
      if (arity.TypeOfK == typeof(bool)) return ((bool)e) ? "1" : "0";
      if (arity.TypeOfK == typeof(double)) return ((double)e).ToString(CultureInfo.InvariantCulture);
      else return e.ToString();
    };

Just added a check for double.

I hope this can fixed as it would suck if someone uses bling to create cool apps and norweigans, swedes, danes and germans can't use them.

I attached the patched file.