Struct rsjsonnet_front::Session

pub struct Session { /* private fields */ }

Implementations

impl Session

pub fn new() -> Self

pub fn program(&self) -> &Program

Returns a reference to the underlying Program.

pub fn program_mut(&mut self) -> &mut Program

Returns a mutable reference to the underlying Program.

pub fn set_max_trace(&mut self, max_trace: usize)

Sets the maximum number of stack trace items to print.

pub fn add_search_path(&mut self, path: PathBuf)

pub fn add_native_func<const N: usize, F>( &mut self, name: &str, params: &[&str; N], func: F, )

where F: FnMut(&mut Program, &[Value; N]) -> Result<Value, String> + 'static,

Adds a native function.

Example

let mut session = rsjsonnet_front::Session::new();

session.add_native_func("MyFunc", &["arg"], |_, [arg]| {
    let Some(arg) = arg.to_string() else {
        return Err("expected a string".into());
    };

    // Count lowercase vowels.
    let r = arg
        .chars()
        .filter(|chr| matches!(chr, 'a' | 'e' | 'i' | 'o' | 'u'))
        .count();
    Ok(rsjsonnet_lang::program::Value::number(r as f64))
});

let source = br#"local f = std.native("MyFunc"); f("hello world")"#;
let thunk = session
    .load_virt_file("<example>", source.to_vec())
    .unwrap();

let result = session.eval_value(&thunk).unwrap();

assert_eq!(result.as_number(), Some(3.0));

pub fn load_virt_file( &mut self, repr_path: &str, data: Vec<u8>, ) -> Option<Thunk>

Loads a file with the provided data.

repr_path is used to represent the file in error messages and for std.thisFile.

In case of failure, the error is printed to stderr and None is returned.

pub fn load_real_file(&mut self, path: &Path) -> Option<Thunk>

Loads a file from the filesystem.

In case of failure, the error is printed to stderr and None is returned.

pub fn eval_value(&mut self, thunk: &Thunk) -> Option<Value>

Evaluates a thunk.

In case of failure, the error is printed to stderr and None is returned.

pub fn eval_call( &mut self, func: &Thunk, pos_args: &[Thunk], named_args: &[(InternedStr, Thunk)], ) -> Option<Value>

Evaluates a function call.

In case of failure, the error is printed to stderr and None is returned.

pub fn manifest_json( &mut self, value: &Value, multiline: bool, ) -> Option<String>

Marshals a value as JSON.

In case of failure, the error is printed to stderr and None is returned.

pub fn print_error(&self, msg: &str)

pub fn print_note(&self, msg: &str)

pub fn push_custom_stack_trace_item(&mut self, text: String)

Pushes a custom item that will be included at the end of stack straces.

pub fn pop_custom_stack_trace_item(&mut self)

Removes the last item pushed with Session::push_custom_stack_trace_item.

Trait Implementations

impl Default for Session

fn default() -> Self

Returns the “default value” for a type.