1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
use super::ast;
use super::runtime::{advance_v, Term, Value};
use std::rc::Rc;
pub const B_INTEGER_EQ0: &str = "int.eq0?";
pub const B_INTEGER_INCREMENT: &str = "int.increment";
pub fn make_boolean_true_function() -> Term {
let x = advance_v();
let y = advance_v();
Term::Abstraction(x, Rc::new(Term::Abstraction(y, Rc::new(Term::Variable(x)))))
}
pub fn make_boolean_false_function() -> Term {
let x = advance_v();
let y = advance_v();
Term::Abstraction(x, Rc::new(Term::Abstraction(y, Rc::new(Term::Variable(y)))))
}
pub fn make_identity_function() -> Term {
let v = advance_v();
Term::Abstraction(v, Rc::new(Term::Variable(v)))
}
pub fn try_ast_symbol_to_builtin_term(symbol: &ast::Symbol) -> Option<Term> {
match symbol.as_str() {
"true" => Some(make_boolean_true_function()),
"false" => Some(make_boolean_false_function()),
"id" => Some(make_identity_function()),
B_INTEGER_EQ0 => Some(Term::Builtin(String::from(B_INTEGER_EQ0))),
B_INTEGER_INCREMENT => Some(Term::Builtin(String::from(B_INTEGER_INCREMENT))),
_ => None,
}
}
pub fn evaluate_builtin(symbol: &String, rhs: Rc<Term>) -> Result<(Rc<Term>, usize), String> {
let result_term = match symbol.as_str() {
B_INTEGER_EQ0 => match &*rhs {
Term::Primitive(primitive) => match primitive {
Value::Integer(value) => {
if *value == 0 {
make_boolean_true_function()
} else {
make_boolean_false_function()
}
}
other => {
return Err(format!(
"[runtime] cannot apply builtin {} to argument type {}",
symbol, other
))
}
},
_ => return Ok((Rc::new(Term::Builtin(symbol.clone())), 0)),
},
B_INTEGER_INCREMENT => match &*rhs {
Term::Primitive(primitive) => match primitive {
Value::Integer(value) => Term::Primitive(Value::Integer(value + 1)),
other => {
return Err(format!(
"[runtime] cannot apply builtin {} to argument type {}",
symbol, other
))
}
},
_ => return Ok((Rc::new(Term::Builtin(symbol.clone())), 0)),
},
_ => return Err(format!("[runtime] invalid builtin evaluated: {}", symbol)),
};
Ok((Rc::new(result_term), 1))
}
|
