std.csv | Zero

When To Use std.csv

In Zerolang, use std.csv for allocation-free CSV validation, record scanning, field decoding, and small fixed-arity CSV writers.

Runnable today:

API	Return	Notes
`std.csv.valid(bytes)`	`Bool`	Validates bounded CSV input with quoted fields and CRLF or LF records.
`std.csv.recordCount(bytes)`	`Maybe<usize>`	Counts valid records, returning null on malformed input.
`std.csv.record(bytes, index)`	`Maybe<Span<u8>>`	Borrows one record slice by ordinal, excluding the line terminator.
`std.csv.fieldCount(record)`	`Maybe<usize>`	Counts fields in one valid record.
`std.csv.field(buffer, record, index)`	`Maybe<Span<u8>>`	Decodes one field into caller storage.
`std.csv.encodedFieldLen(field)`	`usize`	Computes the bytes needed to write one CSV field.
`std.csv.writeField(buffer, field)`	`Maybe<Span<u8>>`	Writes one CSV field with quotes when required.
`std.csv.writeRecord2(buffer, left, right)`	`Maybe<Span<u8>>`	Writes a two-field record ending in `\n`.
`std.csv.writeRecord3(buffer, first, second, third)`	`Maybe<Span<u8>>`	Writes a three-field record ending in `\n`.

Metadata labels:

effects: parse
allocation behavior: no allocation; decoded fields and writer output use caller storage
target support: target-neutral
error behavior: Maybe helpers return null on malformed input or insufficient storage
ownership notes: records borrow from the input; fields and writer output borrow from caller buffers
examples: conformance/native/pass/std-csv.graph

Example

pub fn main(world: World) -> Void raises {    let input: Span<u8> = "name,quote\nAda,\"a,b\"\n"    let record: Maybe<Span<u8>> = std.csv.record(input, 1_usize)    var field_buf: [16]u8 = [0_u8; 16]    var quote: Maybe<Span<u8>> = null    if record.has {        quote = std.csv.field(field_buf, record.value, 1_usize)    }    if std.csv.valid(input) && quote.has && std.mem.eql(quote.value, "a,b") {        check world.out.write("csv ok\n")    }}

Design Notes

CSV helpers follow the common RFC 4180 field rules: comma-separated fields, quoted fields, doubled quotes inside quoted fields, and CRLF or LF record separators. Quoted fields may contain newlines.

The writer surface is fixed-arity. Use writeField when a custom writer loop is needed.