Add support for currently unsupported Postgres multirange functions

[guissalustiano]

Diesel is on path to supports the Postgres multirange type. This is a tracking issue for adding support for the type and it operators.

Type:

• Multirange type on diesel - Add support for the postgres multirange type #4159
• Generate multirange type on Diesel CLI - add multirange to diesel_cli #4183

Operator list:

• anymultirange @> anymultirange → boolean - Does the first multirange contain the second?
• anymultirange @> anyrange → boolean - Does the multirange contain the range?
• anymultirange @> anyelement → boolean - Does the multirange contain the element?
• anyrange @> anymultirange → boolean - Does the range contain the multirange?
• anymultirange <@ anymultirange → boolean - Is the first multirange contained by the second?
• anymultirange <@ anyrange → boolean - Is the multirange contained by the range?
• anyrange <@ anymultirange → boolean - Is the range contained by the multirange?
• anyelement <@ anymultirange → boolean - Is the element contained by the multirange?
• anymultirange && anymultirange → boolean - Do the multirange overlap, that is, have any elements in common?
• anymultirange && anyrange → boolean - Does the multirange overlap the range?
• anyrange && anymultirange → boolean - Does the range overlap the multirange?
• anymultirange << anymultirange → boolean - Is the first multirange strictly left of the second?
• anymultirange << anyrange → boolean - Is the multirange strictly left of the range?
• anyrange << anymultirange → boolean - Is the range strictly left of the multirange?
• anymultirange >> anymultirange → boolean - Is the first multirange strictly right of the second?
• anymultirange >> anyrange → boolean - Is the multirange strictly right of the range?
• anyrange >> anymultirange → boolean - Is the range strictly right of the multirange?
• anymultirange &< anymultirange → boolean - Does the first multirange not extend to the right of the second?
• anymultirange &< anyrange → boolean - Does the multirange not extend to the right of the range?
• anyrange &< anymultirange → boolean - Does the range not extend to the right of the multirange?
• anymultirange &> anymultirange → boolean - Does the first multirange not extend to the left of the second?
• anymultirange &> anyrange → boolean - Does the multirange not extend to the left of the range?
• anyrange &> anymultirange → boolean - Does the range not extend to the left of the multirange?
• anymultirange -|- anymultirange → boolean - Are the multiranges adjacent?
• anymultirange -|- anyrange → boolean - Is the multirange adjacent to the range?
• anyrange -|- anymultirange → boolean - Computes the union of the multiranges. The multiranges need not overlap or be adjacent.
• anymultirange * anymultirange → anymultirange - Computes the intersection of the multiranges.
• anymultirange - anymultirange → anymultirange - Computes the difference of the multiranges.

Function list

• lower ( anymultirange ) → anyelement - Extracts the lower bound of the multirange (NULL if the multirange is empty has no lower bound).
• upper ( anymultirange ) → anyelement - Extracts the upper bound of the multirange (NULL if the multirange is empty or has no upper bound).
• isempty ( anymultirange ) → boolean - Is the multirange empty?
• lower_inc ( anymultirange ) → boolean - Is the multirange's lower bound inclusive?
• upper_inc ( anymultirange ) → boolean - Is the multirange's upper bound inclusive?
• lower_inf ( anymultirange ) → boolean - Does the multirange have no lower bound? (A lower bound of -Infinity returns false.)
• upper_inf ( anymultirange ) → boolean - Does the multirange have no upper bound? (An upper bound of Infinity returns false.)
• range_merge ( anymultirange ) → anyrange - Computes the smallest range that includes the entire multirange.
• multirange ( anyrange ) → anymultirange - Returns a multirange containing just the given range.
• unnest ( anymultirange ) → setof anyrange - Expands a multirange into a set of ranges. The ranges are read out in storage order (ascending).

Multiple functions and operators are the same of the range type, so we can use a helper type (e.g. MultirangeOrRangeMaybeNullable) and use the same function call (e.g. lower)

[wowinter13]

We'll soon have a loooooot of work, I suppose 😄

[guissalustiano]

I noticed that this would be easier than I thought, so I'm taking off the help wanted label and finishing it by myself.