Query syntax: Add support for spaces in field names

[mikegoatly]

At the moment fields can be registered statically or dynamically with spaces in them:

var index = new FullTextIndexBuilder<int>()
    .WithObjectTokenization<Customer>(o => o
      .WithId(c => c.CustomerId)
      .WithField("Customer Name", c=>c.Name)

But there's no way using the LIFTI query syntax to filter on a field name with a space in it:

Customer Name=Something

The first part of the field name becomes part of the query.

We need to introduce something to quote a field name, e.g.

[Customer Name]=Something

We'd need to allow for edge cases where the field name contains a close bracket and it needs to be escaped.

[h0lg]

It would also be be nice to match multiple fields against the same expression. Let's assume I want to match the same query against the UTF8 and the ASCII representation of a customer name:

var index = new FullTextIndexBuilder<int>()
    .WithObjectTokenization<Customer>(o => o
      .WithId(c => c.CustomerId)
      .WithField("Customer Name", c => c.Name)
      .WithField("Customer ASCII Name", c => c.AsciiName)

If possible, I'd like a query without repetition, e.g. [Customer Name|Customer ASCII Name]=Something

Or let's assume I want to search a group of dynamic fields sharing the same same prefix or suffix -
then I'd like to query those with [prefix*]=query or [*suffix]=query.

Obviously, this can be worked around by OR-combining the same query for different field names - so it may really just a be a convenience feature for people manually writing LIFTI queries.

[mikegoatly]

Nice - I like the idea of being able to wildcard a field name in the query - with a dynamic field the exact names of all the fields might not be known.

[mikegoatly]

@h0lg out of interest, what's your use-case for wanting a suffix wildcard match, e.g. [*suffix]=query? I can understand the need for the prefix one to allow for searching across all dynamic fields with a given prefix, but I'm not sure about the suffix one.

[mikegoatly]

I'm going to split wildcards out to #77 - they add significant complexity and implementing this feature without them add its own value.

[h0lg]

@h0lg out of interest, what's your use-case for wanting a suffix wildcard match, e.g. [*suffix]=query? I can understand the need for the prefix one to allow for searching across all dynamic fields with a given prefix, but I'm not sure about the suffix one.

I could get the idea to group fields by a common name suffix instead of a common name prefix;

e.g. if I wanted to search Customers from your above example by [* Name]=Mike.

[mikegoatly]

This is completed and will be in the v6 release