Date parsing not fully RFC 3339 compatible

[mmakaay]

Using the following input:

date = 2019-10-10t11:12:13z

I get the error:
Error decoding TOML: Near line 1 (last key parsed ''): expected a top-level item to end with a newline, comment, or EOF, but got 't' instead

The expected output is something like:

{
   "date" : {
      "type" : "datetime",
      "value" : "2019-10-10T11:12:13Z"
   }
}

According to RFC 3339 and the toml ABNF, the "T" and "Z" part of a date/time value are case insensitive and can therefore be lower case characters.

[mmakaay]

Funny, the github syntax highlighter does approve of the "t", but not the "z", but they both are valid for date/time definitions.

[arp242]

It looks like this is a limitation of the Go time package, which looks just at Z (and T).

RFC 3339 says:

  NOTE: Per [ABNF] and ISO8601, the "T" and "Z" characters in this
  syntax may alternatively be lower case "t" or "z" respectively.

  This date/time format may be used in some environments or contexts
  that distinguish between the upper- and lower-case letters 'A'-'Z'
  and 'a'-'z' (e.g. XML).  Specifications that use this format in
  such environments MAY further limit the date/time syntax so that
  the letters 'T' and 'Z' used in the date/time syntax must always
  be upper case.  Applications that generate this format SHOULD use
  upper case letters.

So it doesn't strictly disallow limiting to just an upper-case "Z" or "T" and implementations MAY limit this.

I'm not super-pedantic about allowing a t or z, but working around the Go time package parsing is probably a bit too much; I found this open issue for it, so ideally that should really be fixed first.