feat(rust,python,cli): add SQL engine support for LIKE and ILIKE pattern matching

[alexander-beedie]

Closes #12399.
Closes #9104.

A long-requested addition, implementing LIKE and ILIKE for the SQL interface (though this first cut does not yet support the optional follow-on ESCAPE clause).

Rewrites the given pattern as a regular expression match, appropriately escaping special characters and replacing % and _ with .* and ., before dispatching the translated pattern to str().contains. Has a simple fast-path if the pattern contains no wildcard characters (and is not case insensitive).

Examples

import polars as pl

df = pl.DataFrame(
    data = [
        ("Dubai", 3564931),
        ("Abu Dhabi", 1807000),
        ("Sharjah", 1405000),
        ("Al Ain", 846747),
        ("Ajman", 490035),
        ("Ras Al Khaimah", 191753),
        ("Fujairah", 118933),
        ("Umm Al Quwain", 59098), 
    ],
    schema = {"City": pl.String, "Population": pl.Int32},
)

with pl.SQLContext(cities=df, eager_execution=True) as ctx:
    print( ctx.execute("SELECT * FROM cities WHERE City LIKE '%D%i'") )
    # ┌───────────┬────────────┐
    # │ City      ┆ Population │
    # │ ---       ┆ ---        │
    # │ str       ┆ i32        │
    # ╞═══════════╪════════════╡
    # │ Dubai     ┆ 3564931    │
    # │ Abu Dhabi ┆ 1807000    │
    # └───────────┴────────────┘
    print( ctx.execute("SELECT * FROM cities WHERE City ILIKE '%al%'") )
    # ┌────────────────┬────────────┐
    # │ City           ┆ Population │
    # │ ---            ┆ ---        │
    # │ str            ┆ i32        │
    # ╞════════════════╪════════════╡
    # │ Al Ain         ┆ 846747     │
    # │ Ras Al Khaimah ┆ 191753     │
    # │ Umm Al Quwain  ┆ 59098      │
    # └────────────────┴────────────┘
    print( ctx.execute("SELECT * FROM cities WHERE City LIKE '%a__a%'") )
    # ┌────────────────┬────────────┐
    # │ City           ┆ Population │
    # │ ---            ┆ ---        │
    # │ str            ┆ i32        │
    # ╞════════════════╪════════════╡
    # │ Sharjah        ┆ 1405000    │
    # │ Ras Al Khaimah ┆ 191753     │
    # │ Fujairah       ┆ 118933     │
    # └────────────────┴────────────┘

[ritchie46]

Yes, this one is a must!