Struct wlambda::compiler::GlobalEnv

pub struct GlobalEnv { /* fields omitted */ }

Holds global environment variables.

This data structure is part of the API. It's there to make functions or values available to a WLambda program.

This environment structure is usually wrapped inside an EvalContext which augments it for calling the compiler and allows evaluation of the code.

See also GlobalEnv::add_func() of how to create a function and put it into the global variable. And GlobalEnv::set_var(). And GlobalEnv::get_var().

Methods

impl GlobalEnv

pub fn add_func<T>(
    &mut self,
    fnname: &str,
    fun: T,
    min_args: Option<usize>,
    max_args: Option<usize>
) where
    T: 'static + Fn(&mut Env, usize) -> Result<VVal, StackAction>, 

Adds a function to a GlobalEnv.

This is an example of how to add a function:

use wlambda::compiler::GlobalEnv;
use wlambda::vval::{Env, VVal};

let g = GlobalEnv::new();
g.borrow_mut().add_func(
    "push",
    |env: &mut Env, argc: usize| {
        if argc < 2 { return Ok(VVal::Nul); }
        let v = env.arg(0);
        v.push(env.arg(1).clone());
        Ok(v.clone())
    }, Some(2), Some(2));

 

pub fn set_var(&mut self, var: &str, val: &VVal)

Sets a global variable to a value.

See also EvalContext::set_global_var()

pub fn get_var(&mut self, var: &str) -> Option<VVal>

Returns the value of a global variable.

See also EvalContext::get_global_var()

pub fn set_resolver(&mut self, res: Rc<RefCell<dyn ModuleResolver>>)

pub fn new() -> GlobalEnvRef

Creates a new GlobalEnv.

Trait Implementations

impl Clone for GlobalEnv

fn clone(&self) -> GlobalEnv

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for GlobalEnv

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

Formats the value using the given formatter.