Fails to parse TypedString expressions in BigQuery with triple quoted strings

[MartinSahlen]

i.e

select JSON """{"name": "Alice", "age": 30}"""

fails. More examples can also be found here.

I also tried to do things like SELECT timestamp """{"name": "Alice", "age": 30}""" which also fails.

Error message is:

called `Result::unwrap()` on an `Err` value: ParserError("Expected: end of statement, found: \"\"\"{\"name\": \"Alice\", \"age\": 30}\"\"\" at Line: 7, Column: 13")

[graup]

The issue here is that parse_literal_string which is used by TypedString doesn't support quote styles other than single or double quoted strings.

Trying to fix this I came across two related issues:

• currently TypedString doesn't retain any knowledge about the used quote style, so it doesn't roundtrip properly. It always formats as a single quoted string.
  • We can fix this by making TypedString contain a Value instead of a String. This also gives us support for other quote styles, addressing the issue reported here.
• fmt::Display for EscapeQuotedString doesn't take into account the dialect, producing strings like 'foo''bar' which is invalid in BQ (should be 'foo\'bar'). So something like this SELECT JSON "{\"foo\":\"bar's\"}" currently also doesn't get formatted correctly
  • Not sure how to fix this one, seems a bit more involved.

I'll push a PR addressing this in a moment.