lsts 0.6.34

Large Scale Type Systems
Documentation 
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use lsts::tlc::TLC;

#[test]
fn check_simplytyped() {
   let mut tlc = TLC::new();

   //inhabited types must be defined
   tlc.check(None, "type Ab; let a: Ab;").unwrap();
   tlc.check(None, "let a: Ab;").unwrap_err();

   //unexpected argument B to function A -> B
   tlc.check(None, "type Ab; type Bc; let a: (Ab,)->Bc; let b: Ab; a(b);").unwrap();
   tlc.check(None, "type Ab; type Bc; let a: (Ab,)->Bc; let b: Bc; a(b);").unwrap_err();
}

#[test]
fn check_normalization() {
   let mut tlc = TLC::new();

   //types should be normalized during unification
   tlc.check(None, "type Ab; type Bc; type Cd; let a: Ab+Bc*Cd; a:Cd*Bc+Ab;").unwrap(); 
}

#[test]
fn check_subtyping() {
   let mut tlc = TLC::new();

   //the type system should accept subtyping relationships
   tlc.check(None, "type Ab; type Bc; type Cd; let a: Ab+Bc; a:Ab;").unwrap(); 
   tlc.check(None, "type Ab; type Bc; type Cd; let a: Ab+Bc; a:Bc;").unwrap(); 
   tlc.check(None, "type Ab; type Bc; type Cd; let a: Ab+Bc; a:Cd;").unwrap_err(); 
}

#[test]
fn check_narrow_implication() {
   let mut tlc = TLC::new();
   
   //narrow subtyping truth table, Bc => Ab
   tlc.check(None, "type Ab; type Bc: Ab; let a: Ab; a:Ab;").unwrap();     //Ab implies        Ab
   tlc.check(None, "type Ab; type Bc: Ab; let a: Ab; a:Bc;").unwrap_err(); //Ab does not imply Bc
   tlc.check(None, "type Ab; type Bc: Ab; let a: Bc; a:Ab;").unwrap();     //Bc implies        Ab
   tlc.check(None, "type Ab; type Bc: Ab; let a: Bc; a:Bc;").unwrap();     //Bc implies        Bc
}

#[test]
fn check_narrow_implication_with_parameters() {
   let mut tlc = TLC::new();
   
   //narrow subtyping truth table, Bc<Pt> => Ab<Pt>
   tlc.check(None, "type Pt; type Ab<A>; type Bc<B>: Ab<B>; let a: Ab<Pt>; a:Ab<Pt>;").unwrap();     //Ab<Pt> implies        Ab<Pt>
   tlc.check(None, "type Pt; type Ab<A>; type Bc<B>: Ab<B>; let a: Ab<Pt>; a:Bc<Pt>;").unwrap_err(); //Ab<Pt> does not imply Bc<Pt>
   tlc.check(None, "type Pt; type Ab<A>; type Bc<B>: Ab<B>; let a: Bc<Pt>; a:Ab<Pt>;").unwrap();     //Bc<Pt> implies        Ab<Pt>
   tlc.check(None, "type Pt; type Ab<A>; type Bc<B>: Ab<B>; let a: Bc<Pt>; a:Bc<Pt>;").unwrap();     //Bc<Pt> implies        Bc<Pt>
}

#[test]
fn check_products_and_ratios() {
   let mut tlc = TLC::new();

   //ratio types and product types are rational
   tlc.check(None, "type At; let a: At*At; a:At*At;").unwrap();
   tlc.check(None, "type At; let a: At*At; a:?;").unwrap();
   tlc.check(None, "type At; let a: At*At; a:?/();").unwrap();
   tlc.check(None, "type At; let a: At*At; a:At;").unwrap_err();
   tlc.check(None, "type At; let a: At*At/At; a:At;").unwrap();
   tlc.check(None, "type At; let a: At*At/At; a:?;").unwrap();
   tlc.check(None, "type At; let a: At*At/At; a:?/();").unwrap();
   tlc.check(None, "type At; let a: At/At; a:();").unwrap();
   tlc.check(None, "type At; let a: At/At; a:?;").unwrap();
   tlc.check(None, "type At; let a: At/At; a:?/();").unwrap();
   tlc.check(None, "type At; let a: At/At; a:At;").unwrap_err();
   tlc.check(None, "type At; let a: At/At*At; a:At;").unwrap_err();
   tlc.check(None, "type At; let a: At/At*At; a:()/At;").unwrap();
   tlc.check(None, "type At; let a: At/At*At; a:()/At*At;").unwrap_err();
   tlc.check(None, "type At; let a: At/At*At; a:?/();").unwrap_err();
}

#[test]
fn check_kinded_polymorphism() {
   let mut tlc = TLC::new();

   //unification is kind sensitive
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Bc; let c:Ab = a;").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Bc; let c:Bc = b;").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Bc; let c:Ab+Bc = a;").unwrap_err();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Bc; let c:Ab+Bc = b;").unwrap_err();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Bc; let c:Ab = b;").unwrap_err();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Bc; let c:Bc = a;").unwrap_err();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Ab+Bc; let c:Ab = a;").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Ab+Bc; let c:Bc = a;").unwrap_err();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Ab+Bc; let c:Ab = b;").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let a:Ab; let b:Ab+Bc; let c:Bc = b;").unwrap();
}

#[test]
fn check_kinded_parametric_polymorphism() {
   let mut tlc = TLC::new();

   //unification is kind sensitive
   tlc.check(None, "type Ab::Term; type Bc::BKind; let f(x:Ab::Term); let f(x:Bc::BKind); let x:Ab; f(x);").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let f(x:Ab::Term); let f(x:Bc::BKind); let x:Bc; f(x);").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let f(x:Ab::Term); let f(x:Bc::BKind); let x:Ab+Bc; f(x);").unwrap(); //Permitted to match multiple

   //parameters can be inferred by kind
   tlc.check(None, "type Ab::Term; type Bc::BKind; let f(x:X::Term); let f(x:X::BKind); let x:Ab; f(x);").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let f(x:X::Term); let f(x:X::BKind); let x:Bc; f(x);").unwrap();
   tlc.check(None, "type Ab::Term; type Bc::BKind; let f(x:X::Term); let f(x:X::BKind); let x:Ab+Bc; f(x);").unwrap(); //Permitted to match multiple
}

/*
#[test]
fn check_functions() {
   let mut tlc = TLC::new();

   //function application is narrowly typed
   tlc.check(None, "type Aa::Ka; type Bb; let f(X::Ka):X; let x: Aa+Bb; f(x): Aa;").unwrap();
   tlc.check(None, "type Aa::Ka; type Bb; let f(X::Ka):X; let x: Aa+Bb; f(x): Bb;").unwrap_err();

   //default kind is Term
   //there is no Any kind
   tlc.check(None, "type Aa::Ka; type Bb; let f(X):X; let x: Aa+Bb; f(x): Aa;").unwrap_err();
   tlc.check(None, "type Aa::Ka; type Bb; let f(X):X; let x: Aa+Bb; f(x): Bb;").unwrap();
}
*/