Enum Target 

#[non_exhaustive]
pub enum Target {
    Djot,
    Markdown,
    Xml,
    Html,
    Asciidoc,
    Runtime(RuntimeId),
}

Every format Twig can write — the output axis, as opposed to Format, which is what Twig can parse.

Every Format is also a Target (use Target::from(format)), so the two lists coincide today and the distinction costs nothing to ignore. It exists because only one of them can grow freely: a Format must have a parser behind it, while a target only needs somewhere for bytes to go. That makes an export-only target — one Twig can write and no parser reads back, PDF being the motivating case — expressible here and nowhere else. See the two format axes in the Zig library’s DESIGN.md.

#[non_exhaustive] for exactly that reason: a future export-only variant is then an additive change rather than a breaking one for callers that match on this enum.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Djot

Markdown

Xml

Html

Asciidoc

AsciiDoc source, in Asciidoctor’s idiomatic spellings: = Title, *strong* where the boundaries allow and **strong** where they do not, [source,lang] listings, |=== tables, footnote:[] macros.

Runtime(RuntimeId)

A registered language, as a place to write to. Serializing to one that declared no print is Error::UnsupportedFormat.

Implementations

impl Target

pub fn as_format(self) -> Option<Format>

The Format whose parser reads this target’s own output back, or None for an export-only target.

Always Some today. It is the question to ask before assuming a target can be round-tripped: None means bytes go out and nothing comes back, so there is no “parse it again and compare” available for that target.

pub fn code(self) -> c_int

The C ABI’s code for this target. See Format::code.

pub fn name(self) -> &'static str

The name this target answers to. See Format::name.

Trait Implementations

impl Clone for Target

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Target

impl Debug for Target

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Target

impl From<Format> for Target

Total: every input format is also an output target, even the ones with no serializer yet (converting into XML reports Error::UnsupportedFormat rather than being unnameable). A dialect lands on its language’s target — Format::Commonmark and Format::Gfm both write as Target::Markdown — so Target does not grow a row per dialect.

fn from(value: Format) -> Self

Converts to this type from the input type.

impl From<Target> for TwigFormat

Panics on Target::Runtime; use Target::code.

fn from(value: Target) -> Self

Converts to this type from the input type.

impl PartialEq for Target

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Target