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|
use crate::{
lisp::{
error::{EvalError, LispError},
expr::LispExpr,
number::LispNumber,
Environment,
},
primitive,
};
use std::convert::TryInto;
#[macro_export]
macro_rules! primitive {
($env:expr, $arity:expr, $name:expr, $closure:expr) => {
let val = crate::lisp::expr::LispExpr::PrimitiveFunc(crate::lisp::expr::PrimitiveFunc {
arity: $arity,
closure: $closure,
});
let _ = $env.insert($name.to_string(), val);
};
}
pub fn new_env() -> Environment {
let mut env = Environment::new();
primitive!(env, Some(2), "+", |args, _| {
let nums = args
.into_iter()
.map(|arg| arg.try_into())
.collect::<Result<Vec<&LispNumber>, LispError>>()?;
return Ok(LispExpr::Number(
nums.iter().fold(LispNumber::Integer(0), |acc, &x| acc + *x),
));
});
primitive!(env, Some(2), "-", |args, _| {
let nums = args
.into_iter()
.map(|arg| arg.try_into())
.collect::<Result<Vec<&LispNumber>, LispError>>()?;
let mut acc = nums[0].clone();
for arg in nums.into_iter().skip(1) {
acc = acc - *arg;
}
Ok(LispExpr::Number(acc))
});
primitive!(env, Some(2), "*", |args, _| {
let nums = args
.into_iter()
.map(|arg| arg.try_into())
.collect::<Result<Vec<&LispNumber>, LispError>>()?;
return Ok(LispExpr::Number(
nums.iter().fold(LispNumber::Integer(1), |acc, &x| acc * *x),
));
});
primitive!(env, Some(2), "/", |args, _| {
let nums = args
.into_iter()
.map(|arg| arg.try_into())
.collect::<Result<Vec<&LispNumber>, LispError>>()?;
let mut acc = nums[0].clone();
for arg in nums.into_iter().skip(1) {
acc = acc.div(*arg)?;
}
Ok(LispExpr::Number(acc))
});
primitive!(env, Some(0), "toggle-grid", |_, app| {
app.toggle_grid();
Ok(LispExpr::Unit)
});
primitive!(env, Some(3), "if", |args, _| {
match args {
[predicate, then, else_] => {
if matches!(predicate, LispExpr::BoolLit(false)) {
Ok(else_.clone())
} else {
Ok(then.clone())
}
}
_ => {
panic!("panicked at `if` expression")
}
}
});
primitive!(env, Some(2), "and", |args, _| {
if args
.iter()
.any(|arg| matches!(arg, LispExpr::BoolLit(false)))
{
Ok(LispExpr::BoolLit(false))
} else {
Ok(LispExpr::BoolLit(true))
}
});
primitive!(env, Some(2), "or", |args, _| {
if args
.iter()
.any(|arg| matches!(arg, LispExpr::BoolLit(true)))
{
Ok(LispExpr::BoolLit(true))
} else {
Ok(LispExpr::BoolLit(false))
}
});
primitive!(env, Some(1), "not", |args, _| {
match args {
[val] => {
if matches!(val, LispExpr::BoolLit(false)) {
Ok(LispExpr::BoolLit(true))
} else {
Ok(LispExpr::BoolLit(false))
}
}
_ => Err(EvalError::ArgumentCount(Some(1)).into()),
}
});
primitive!(env, None, "begin", |args, _| {
if args.is_empty() {
Err(EvalError::ArgumentCount(None).into())
} else {
Ok(args.into_iter().last().unwrap().clone())
}
});
primitive!(env, Some(0), "quit", |_, app| {
app.quit();
Ok(LispExpr::Unit)
});
env
}
|
