ChDriver.Types (ch_driver v0.1.0)

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Parses ClickHouse's column type strings (e.g. "Nullable(String)", "Map(String, Decimal(10, 2))") into their component parts. Pure string parsing only -- no wire decoding happens here; see ChDriver.Types.Registry for the scalar codec table and ChDriver.Protocol.Block.Wrappers / ChDriver.Protocol.Block.Sparse for how these parsed types drive decoding of wrapper/compound column data.

Every wrapper/compound type ClickHouse's Native block format can send that this driver understands is recognized here:

Tuple(...) is not supported in its own right -- only as Map(K, V)'s implicit internal representation, not as a directly-selectable column type (see ChDriver.Protocol.Block.Wrappers's decode_map/4 moduledoc for why generalizing it is more work than it looks).

Summary

Functions

parse_array(type)

Parses ClickHouse's Array(T) wrapper syntax, returning the inner type string.

parse_decimal(arg1)

Parses Decimal(P, S) and the Decimal32(S)/Decimal64(S)/ Decimal128(S)/Decimal256(S) fixed-precision aliases, returning {:ok, precision, scale}.

parse_fixed_string(arg1)

Parses ClickHouse's FixedString(N) type, returning {:ok, n}.

parse_low_cardinality(type)

Parses ClickHouse's LowCardinality(T) wrapper syntax, returning the inner type string.

parse_map(type)

Parses ClickHouse's Map(K, V) wrapper syntax, returning {:ok, key_type, value_type}. Splits on the top-level comma only (tracking paren depth so e.g. Map(String, Decimal(10, 2)) isn't split on the inner comma).

parse_nullable(type)

Parses ClickHouse's Nullable(T) wrapper syntax, returning the inner type string.

split_top_level_comma(inner)

Splits inner on its top-level comma(s) only, tracking paren depth so a parameterized inner type's own comma (e.g. the Decimal(10, 2) inside Map(String, Decimal(10, 2))) is never mistaken for the wrapper's own separator. Returns the list of (untrimmed) parts, or :error if the parens are unbalanced.

strip_wrapper(type, prefix)

Strips a Prefix(...) wrapper down to its inner contents, given the exact "Prefix(" (including the opening paren) to match against. Not a general parenthesis-balancer -- just strips the given prefix and the trailing ) -- but that's sufficient even for a parameterized inner type like Nullable(DateTime(3)), since the outer ) is always the last byte of the whole type string.

Functions

parse_array(type)

Parses ClickHouse's Array(T) wrapper syntax, returning the inner type string.

parse_decimal(arg1)

Parses Decimal(P, S) and the Decimal32(S)/Decimal64(S)/ Decimal128(S)/Decimal256(S) fixed-precision aliases, returning {:ok, precision, scale}.

parse_fixed_string(arg1)

Parses ClickHouse's FixedString(N) type, returning {:ok, n}.

parse_low_cardinality(type)

Parses ClickHouse's LowCardinality(T) wrapper syntax, returning the inner type string.

parse_map(type)

Parses ClickHouse's Map(K, V) wrapper syntax, returning {:ok, key_type, value_type}. Splits on the top-level comma only (tracking paren depth so e.g. Map(String, Decimal(10, 2)) isn't split on the inner comma).

parse_nullable(type)

Parses ClickHouse's Nullable(T) wrapper syntax, returning the inner type string.

split_top_level_comma(inner)

Splits inner on its top-level comma(s) only, tracking paren depth so a parameterized inner type's own comma (e.g. the Decimal(10, 2) inside Map(String, Decimal(10, 2))) is never mistaken for the wrapper's own separator. Returns the list of (untrimmed) parts, or :error if the parens are unbalanced.

strip_wrapper(type, prefix)

Strips a Prefix(...) wrapper down to its inner contents, given the exact "Prefix(" (including the opening paren) to match against. Not a general parenthesis-balancer -- just strips the given prefix and the trailing ) -- but that's sufficient even for a parameterized inner type like Nullable(DateTime(3)), since the outer ) is always the last byte of the whole type string.