BigQuery Parameter Names allow more characters than currently permitted

[tunetheweb]

We have an issue whereby the following are not accepted in BigQuery linting:

CREATE TEMP FUNCTION
qs(
    y STRING
)
RETURNS STRUCT<_product_id ARRAY<INT64>>
LANGUAGE js AS """
    CODE GOES HERE
"""

The underscore in _product_id is unparsable.

The BigQuery documentation on identifiers has this to say:

Unquoted identifiers must begin with a letter or an underscore character. Subsequent characters can be letters, numbers, or underscores.

Similarly, this doesn't work:

CREATE TEMP FUNCTION
qs(
    y STRING
)
RETURNS STRUCT<`$=` ARRAY<INT64>>
LANGUAGE js AS """
    CODE GOES HERE
"""

even though the documentation has the following to say:

Quoted identifiers must be enclosed by backtick (`) characters.

• Quoted identifiers can contain any character, such as spaces or symbols.
• Quoted identifiers cannot be empty.
• Quoted identifiers have the same escape sequences as string literals.