Struct ScriptSig 

pub struct ScriptSig {
    pub params: Vec<ScriptParam>,
    pub ret: ScriptTy,
    pub variadic: bool,
    pub min_arity: usize,
    pub doc: String,
}

The declared signature of a ScriptFn.

Fields

params: Vec<ScriptParam>

Positional parameters, in order.

ret: ScriptTy

Return type.

variadic: bool

Accepts more arguments than Self::params declares.

min_arity: usize

Smallest accepted argument count. Parameters past it are optional and arrive as ScriptValue::Unit when the call omits them.

doc: String

One-line description, surfaced by editor tooling.

Implementations

impl ScriptSig

pub fn arity_range(&self) -> RangeInclusive<usize>

The inclusive range of argument counts a host binds this signature for.

pub fn is_typed(&self) -> bool

Whether any parameter declares a type.

An all-Any signature says nothing to check, so a host that binds variadically passes whatever the script sent straight through; that is what lumen_app_expose and the SDK’s native_fn describe, and a call with the wrong count reaches the body rather than failing to resolve. Dynamic says as little.

pub fn complete_args(&self, args: &[ScriptValue]) -> Option<Vec<ScriptValue>>

args with each struct argument’s missing fields set to their defaults, or None when the signature takes no struct and args stands as it is.

pub fn check_args(&self, args: &[ScriptValue]) -> Result<(), String>

Check args against the declared parameters. Returns the message a host raises to the script on a mismatch.

Too few arguments is a mismatch; extra arguments are one only when the signature is not variadic. A parameter past Self::min_arity accepts ScriptValue::Unit whatever its declared type, so a host that pads a short call with unit placeholders still passes.

Trait Implementations

impl Clone for ScriptSig

fn clone(&self) -> ScriptSig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ScriptSig

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

Formats the value using the given formatter.

impl Default for ScriptSig

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ScriptSig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ScriptSig

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.