ChDriver.
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Parses ClickHouse column type strings, e.g. "Nullable(String)" or
"Map(String, Decimal(10, 2))", into their component parts.
Pure string parsing — no wire decoding happens here. See
ChDriver.Protocol.Block.Wrappers for how the parsed types drive actual
column decoding.
Supports Nullable(T), Array(T), Map(K, V), LowCardinality(T),
Variant(T1, ..., Tn), Decimal(P, S) (and its
Decimal32/64/128/256(S) aliases), DateTime64(P[, 'TZ']), and
FixedString(N). Tuple(...) isn't supported as a standalone column
type — only as Map's internal representation.
Summary
Functions
Parses ClickHouse's Array(T) wrapper syntax, returning the inner type
string.
Parses ClickHouse's DateTime64(P) and DateTime64(P, 'Timezone')
types, returning {:ok, precision}.
Parses Decimal(P, S) and the Decimal32(S)/Decimal64(S)/
Decimal128(S)/Decimal256(S) fixed-precision aliases, returning
{:ok, precision, scale}.
Parses ClickHouse's FixedString(N) type, returning {:ok, n}.
Parses ClickHouse's LowCardinality(T) wrapper syntax, returning the
inner type string.
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).
Parses ClickHouse's Nullable(T) wrapper syntax, returning the inner
type string.
Parses ClickHouse's Variant(T1, ..., Tn) syntax, returning {:ok, [type_string]} with the alternatives in the order they appear in the
type name -- which is exactly the order the wire discriminator byte
indexes into (ClickHouse normalizes a Variant's alternatives into
sorted order when it resolves the type, so the name as reported on the
wire is authoritative, not the order originally written in DDL).
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.
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
Parses ClickHouse's Array(T) wrapper syntax, returning the inner type
string.
Parses ClickHouse's DateTime64(P) and DateTime64(P, 'Timezone')
types, returning {:ok, precision}.
The timezone argument is deliberately discarded: it only affects how ClickHouse displays and parses the value, never the stored tick count, which is always an offset from the (timezone-agnostic) Unix epoch. Decoding therefore only needs the precision.
Parses Decimal(P, S) and the Decimal32(S)/Decimal64(S)/
Decimal128(S)/Decimal256(S) fixed-precision aliases, returning
{:ok, precision, scale}.
Parses ClickHouse's FixedString(N) type, returning {:ok, n}.
Parses ClickHouse's LowCardinality(T) wrapper syntax, returning the
inner type string.
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).
Parses ClickHouse's Nullable(T) wrapper syntax, returning the inner
type string.
Parses ClickHouse's Variant(T1, ..., Tn) syntax, returning {:ok, [type_string]} with the alternatives in the order they appear in the
type name -- which is exactly the order the wire discriminator byte
indexes into (ClickHouse normalizes a Variant's alternatives into
sorted order when it resolves the type, so the name as reported on the
wire is authoritative, not the order originally written in DDL).
Splits on top-level commas only, so a parameterized alternative like
Variant(Int32, Decimal(10, 2)) isn't split on the inner comma.
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.
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.