syntaxAlchemist/lib-laddertypes
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Merge branch 'topic-parameter-normal-form' into dev

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This commit is contained in:
Michael Sippel 2024-08-05 00:10:03 +02:00
commit a4837038e6
Signed by: senvas
GPG key ID: F96CF119C34B64A6
4 changed files with 156 additions and 0 deletions
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1
src/lib.rs
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@ -7,6 +7,7 @@ pub mod parser;
pub mod unparser;
pub mod curry;
pub mod lnf;
pub mod pnf;
pub mod subtype;
pub mod unification;

113
src/pnf.rs Normal file
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@ -0,0 +1,113 @@
use crate::term::TypeTerm;
//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\
impl TypeTerm {
/// transmute type into Parameter-Normal-Form (PNF)
///
/// Example:
/// ```ignore
/// <Seq <Digit 10>>~<Seq Char>
/// ⇒ <Seq <Digit 10>~Char>
/// ```
pub fn param_normalize(self) -> Self {
match self {
TypeTerm::Ladder(mut rungs) => {
if rungs.len() > 0 {
// normalize all rungs separately
for r in rungs.iter_mut() {
*r = r.clone().param_normalize();
}
// take top-rung
match rungs.remove(0) {
TypeTerm::App(params_top) => {
let mut params_ladders = Vec::new();
let mut tail : Vec<TypeTerm> = Vec::new();
// append all other rungs to ladders inside
// the application
for p in params_top {
params_ladders.push(vec![ p ]);
}
for r in rungs {
match r {
TypeTerm::App(mut params_rung) => {
if params_rung.len() > 0 {
let mut first_param = params_rung.remove(0);
if first_param == params_ladders[0][0] {
for (l, p) in params_ladders.iter_mut().skip(1).zip(params_rung) {
l.push(p.param_normalize());
}
} else {
params_rung.insert(0, first_param);
tail.push(TypeTerm::App(params_rung));
}
}
}
TypeTerm::Ladder(mut rs) => {
for r in rs {
tail.push(r.param_normalize());
}
}
atomic => {
tail.push(atomic);
}
}
}
let head = TypeTerm::App(
params_ladders.into_iter()
.map(
|mut l| {
l.dedup();
match l.len() {
0 => TypeTerm::unit(),
1 => l.remove(0),
_ => TypeTerm::Ladder(l).param_normalize()
}
}
)
.collect()
);
if tail.len() > 0 {
tail.insert(0, head);
TypeTerm::Ladder(tail)
} else {
head
}
}
TypeTerm::Ladder(mut r) => {
r.append(&mut rungs);
TypeTerm::Ladder(r)
}
atomic => {
rungs.insert(0, atomic);
TypeTerm::Ladder(rungs)
}
}
} else {
TypeTerm::unit()
}
}
TypeTerm::App(params) => {
TypeTerm::App(
params.into_iter()
.map(|p| p.param_normalize())
.collect())
}
atomic => atomic
}
}
}
//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>\\

1
src/test/mod.rs
View file

@ -3,6 +3,7 @@ pub mod lexer;
pub mod parser;
pub mod curry;
pub mod lnf;
pub mod pnf;
pub mod subtype;
pub mod substitution;
pub mod unification;

41
src/test/pnf.rs Normal file
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@ -0,0 +1,41 @@
use crate::dict::TypeDict;
#[test]
fn test_param_normalize() {
let mut dict = TypeDict::new();
assert_eq!(
dict.parse("A~B~C").expect("parse error"),
dict.parse("A~B~C").expect("parse error").param_normalize(),
);
assert_eq!(
dict.parse("<A B>~C").expect("parse error"),
dict.parse("<A B>~C").expect("parse error").param_normalize(),
);
assert_eq!(
dict.parse("<A B~C>").expect("parse error"),
dict.parse("<A B>~<A C>").expect("parse error").param_normalize(),
);
assert_eq!(
dict.parse("<A B~C D~E>").expect("parse error"),
dict.parse("<A B D>~<A C D>~<A C E>").expect("parse errror").param_normalize(),
);
assert_eq!(
dict.parse("<Seq <Digit 10>~Char>").expect("parse error"),
dict.parse("<Seq <Digit 10>>~<Seq Char>").expect("parse errror").param_normalize(),
);
assert_eq!(
dict.parse("<A <B C~D~E> F~G H H>").expect("parse error"),
dict.parse("<A <B C> F H H>
~<A <B D> F H H>
~<A <B E> F H H>
~<A <B E> G H H>").expect("parse errror")
.param_normalize(),
);
}