The Fortress Language Specification - CiteSeerX

Values, intermediate expressions, evaluation contexts, redexes, and trait and object names
v ::= O −→ τ { −−−→ x ↦→ v; }
value
ǫ ::= x intermediate expression
| self
| O −→ τ ( −→ ǫ )
| ǫ.x
| ǫ.f −→ τ ( −→ ǫ )
| O −→ τ { −−−→ x ↦→ ǫ; −−−→ x ↦→ ǫ}
E ::= □ evaluation context
| O −→ τ ( −→ ǫ E −→ ǫ )
| E.x
| E.f −→ τ ( −→ ǫ )
| ǫ.f −→ τ ( −→ ǫ E −→ ǫ )
| O −→ τ { −−−→ x ↦→ v; x ↦→ E −−−→ x ↦→ e}
R ::= O −→ τ ( −→ v ) redex
| O −→ τ { −−−→ x ↦→ v; x ↦→ v −−−→ x ↦→ e}
| v.x
| v.f −→ τ ( −→ v )
C ::= T trait name
| O object name
Evaluation rules: p ⊢ E[R] −→ E[ǫ]
[R-OBJECT]
[R-SUB]
object O −−−−−−−−−→ αextends ( −−→ x: )
−−−−−−→
x ′ : = e ′ end ∈ p
p ⊢ E[O −→ τ ( −→ v )] −→ E[O −→ τ { −−−→ x ↦→ v ; −−−−−−−−−−−−−−−→
x ′ ↦→ [ −→ v / −→ x ][ −→ τ / −→ α ]e ′ }]
p ⊢ E[O −→ τ { −−−→ x ↦→ v; y ↦→ v −−−→ z ↦→ e}] −→ E[O −→ τ { −−−→ x ↦→ v y ↦→ v; −−−−−−−→ z ↦→ [v/y]e}]
[R-FIELD]
[R-METHOD]
p ⊢ E[O −→ τ { −−−→ x ↦→ v; }.x i ] −→ E[v i ]
mbody p (f −→ τ ′ , O −→ τ ) = {( −→ x ′ ) → e}
p ⊢ E[O −→ τ { −−−→ x ↦→ v; }.f −→ τ ′ ( −→ v ′ )] −→ E[[ −→ v / −→ x ][O −→ τ { −−−→ x ↦→ v; }/self][ −→ v ′ / −→ x ′ ]e]
Method body lookup: mbody p (f −→ τ , τ) = {( −→ x ) → e}
[MB-SELF]
C −−−−−−−−−→ αextends
−→ fd ∈ p f
−−−−−−−−−→
α ′ extends ( −−→ x ′ : ): = e ∈ { −→ fd }
mbody p (f −→ τ ′ , C −→ τ ) = {[ −→ τ ′ / −→ α ′ ][ −→ τ / −→ α ]( −→ x ′ ) → e}
[MB-SUPER]
C −−−−−−−−−→ αextends extends { −→ K}
mbody p (f −→ τ ′ , C −→ τ ) =
⋃
N i ∈{ −→ N }
−→ fd ∈ p f ∉ {
−−−−−−−→
Fname(fd)}
mbody p (f −→ τ ′ , [ −→ τ / −→ α ]N i )
[MB-OBJ]
mbody p (f −→ τ ,Object) = ∅
Function/method name lookup: Fname(fd) = f
Fname(f −−−−−−−−−→ αextends N( −→ x:τ):τ = e) = f
Figure A.20: Dynamic Semantics of Acyclic Core Fortress with Field Definitions
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