Struct wlambda::compiler::SymbolTable

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pub struct SymbolTable { /* private fields */ }

Expand description

Stores symbols and values for a WLambda module that can be added to a GlobalEnv with set_module.

 use wlambda::{SymbolTable, GlobalEnv, EvalContext, Env};

 let mut st = SymbolTable::new();

 let outbuf = std::rc::Rc::new(std::cell::RefCell::new(String::from("")));

 let captured_outbuf = outbuf.clone();

 st.fun("print", move |e: &mut Env, _argc: usize| {
     std::mem::replace(&mut *captured_outbuf.borrow_mut(), e.arg(0).s());
     println!("MY PRINT: {}", e.arg(0).s());
     Ok(e.arg(0).clone())
 }, Some(1), Some(1), false);

 let global_env = GlobalEnv::new_default();
 global_env.borrow_mut().set_module("my", st);

 let mut ctx = EvalContext::new(global_env);
 ctx.eval("!@import my my; my:print 1337");

 assert_eq!(outbuf.borrow().clone(), "1337");

Implementations

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impl SymbolTable

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pub fn new() -> Self

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pub fn list(&self) -> Vec<String>ⓘNotable traits for Vec<u8, A>`impl<A> Write for Vec<u8, A> where A: Allocator,`

This function returns all symbols defined in this SymbolTable. It’s mainly used for tests.

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pub fn set(&mut self, name: &str, value: VVal)

Sets the entry name to the value. So that the value can be imported.

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pub fn get(&self, name: &str) -> Option<&VVal>

Retrieves a value from the SymbolTable, if present.

use wlambda::{VVal, EvalContext};
let mut ctx = EvalContext::new_default();
ctx.eval("!@export to_rust = 42.0;");

assert_eq!(ctx.get_exports().get("to_rust").cloned(), Some(VVal::Flt(42.0)));

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

Helper function for building symbol tables with functions in them.

See also VValFun::new_fun for more details.

 use wlambda::VVal;
 let mut st = wlambda::compiler::SymbolTable::new();
 st.fun("nothing",
        |e: &mut wlambda::vval::Env, _argc: usize| Ok(VVal::None),
        None, None, false);