Format crates comparison

Per-type and per-attribute support across every facet format crate. Cells link to the test names that back each entry — hover to see them.

Legend: ✅ fully supported with tests · 🟡 partial support or untested · 🚫 not supported · ➖ not applicable

Column abbreviations: msgp = facet-msgpack, pcrd = facet-postcard

Overview

S = serialization, D = deserialization.

Crate	Direction	Format Type	Parser	Showcase
facet-json	SD	Text	Event-based (custom)	🚫
facet-yaml	SD	Text	Event-based (saphyr-parser)	🚫
facet-toml	SD	Text	Event-based (toml_parser)	🚫
facet-xml	SD	Text	Event-based (quick-xml)	🚫
facet-msgpack	SD	Binary	Event-based (custom)	🚫
facet-postcard	SD	Binary	Event-based (custom)	🚫
facet-asn1	S	Binary	(Custom)	🚫
facet-xdr	S	Binary	(Custom)	🚫
figue	D	CLI	(Custom)	Guide
facet-urlencoded	D	Text	form_urlencoded	🚫
facet-csv	S	Text	(Custom)	🚫

Scalar types

Type	json	yaml	toml	xml	msgp	pcrd	asn1	xdr	args	urlenc	csv
bool	✅	✅	✅	🟡	✅	✅	✅	✅	✅	🚫	✅
u8..u64	✅	✅	✅	🟡	✅	✅	✅	✅	✅	✅	✅
i8..i64	✅	✅	✅	🟡	✅	✅	✅	✅	✅	🚫	✅
u128/i128	✅	✅	🟡	🟡	🟡	✅	🟡	🟡	🟡	🟡	🟡
f32/f64	✅	✅	✅	🟡	🚫	✅	✅	✅	✅	🚫	✅
char	🚫	✅	🟡	🟡	✅	✅	🟡	🟡	🚫	🚫	✅
NonZero integers	✅	🟡	🚫	🟡	🟡	🚫	🚫	🚫	🟡	🟡	✅

String types

All formats support String, &str (with best-effort borrowing), and Cow<str>.

Lists, sets, and maps

Type	json	yaml	toml	xml	msgp	pcrd	asn1	xdr	args	urlenc	csv
Vec<T>	✅	✅	✅	✅	✅	✅	✅	✅	✅	🚫	🚫
[T; N] (arrays)	✅	✅	✅	🟡	✅	✅	✅	✅	🟡	🚫	🚫
HashSet<T>	✅	✅	🚫	🟡	🚫	✅	🟡	🚫	🚫	🚫	🚫
BTreeSet<T>	✅	✅	🚫	🟡	🚫	✅	🟡	🚫	🚫	🚫	🚫
HashMap<K, V>	✅	✅	✅	🟡	✅	✅	🟡	🚫	🚫	🚫	🚫
BTreeMap<K, V>	✅	✅	✅	🟡	🟡	✅	🟡	🚫	🚫	🚫	🚫
Non-string map keys	✅	✅	🚫	🚫	✅	✅	🚫	🚫	➖	➖	➖

Compound types

Type	json	yaml	toml	xml	msgp	pcrd	asn1	xdr	args	urlenc	csv
Option<T>	✅	✅	✅	✅	✅	✅	🟡	✅	✅	🚫	✅
Result<T, E>	🚫	🟡	🚫	🚫	🚫	🟡	🚫	🚫	🚫	🚫	🚫

Smart pointers

Type	json	yaml	toml	xml	msgp	pcrd	asn1	xdr	args	urlenc	csv
Box<T>	✅	✅	🚫	🟡	🟡	✅	🟡	🟡	🟡	🚫	🟡
Rc<T>	✅	✅	🚫	🟡	🟡	✅	🟡	🟡	🟡	🚫	🟡
Arc<T>	✅	✅	🚫	🟡	🟡	✅	🟡	🟡	🟡	🚫	🟡

Attributes

Attribute	json	yaml	toml	xml	msgp	pcrd	asn1	xdr	args	urlenc	csv
opaque	✅	🚫	🚫	✅	🚫	🚫	🚫	🚫	🚫	🚫	🚫
proxy	✅	🚫	🚫	✅	🚫	🚫	🚫	🚫	🚫	🚫	🚫