Struct fend_core::Context

pub struct Context { /* private fields */ }

This struct contains fend’s current context, including some settings as well as stored variables.

If you’re writing an interpreter it’s recommended to only instantiate this struct once so that variables and settings are preserved, but you can also manually serialise all variables and recreate the context for every calculation, depending on which is easier.

Implementations

impl Context

pub fn new() -> Self

Create a new context instance.

pub fn set_current_time_v1(&mut self, _ms_since_1970: u64, _tz_offset_secs: i64)

This method currently has no effect!

Set the current time. This API will likely change in the future!

The first argument (ms_since_1970) must be the number of elapsed milliseconds since January 1, 1970 at midnight UTC, ignoring leap seconds in the same way as unix time.

The second argument (tz_offset_secs) is the current time zone offset to UTC, in seconds.

pub fn use_coulomb_and_farad(&mut self)

Define the units C and F as coulomb and farad instead of degrees celsius and degrees fahrenheit.

pub fn set_random_u32_fn(&mut self, random_u32: fn() -> u32)

Set a random number generator

pub fn disable_rng(&mut self)

Clear the random number generator after setting it with via Self::set_random_u32_fn

pub fn set_output_mode_terminal(&mut self)

Change the output mode to fixed-width terminal style. This enables ASCII graphs in the output.

pub fn serialize_variables(&self, write: &mut impl Write) -> Result<(), String>

Serializes all variables defined in this context to a stream of bytes. Note that the specific format is NOT stable, and can change with any minor update.

Errors

This function returns an error if the input cannot be serialized.

pub fn deserialize_variables( &mut self, read: &mut impl Read ) -> Result<(), String>

Deserializes the given variables, replacing all prior variables in the given context.

Errors

Returns an error if the input byte stream is invalid and cannot be deserialized.

pub fn set_exchange_rate_handler_v1<T: ExchangeRateFn + 'static + Send + Sync>( &mut self, get_exchange_rate: T )

Set a handler function for loading exchange rates.

pub fn define_custom_unit_v1( &mut self, singular: &str, plural: &str, definition: &str, attribute: &CustomUnitAttribute )

Trait Implementations

impl Clone for Context

fn clone(&self) -> Context

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Context

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

Formats the value using the given formatter.

impl Default for Context

fn default() -> Self

Returns the “default value” for a type.