## _↓_

#### Definitions:

expression phrase ⇒ boolean, expression phrase ⇒ boolean
Source: /avail/Avail/Foundation/Logic
Categories: Primitives, Logic
Given two arbitrary boolean -valued phrase s, answer a joint denial, i.e., NOR, phrase. The resulting phrase short-circuits the computation, i.e., only evaluates b if a is false.
Position Name Type Description
Parameters
1 a expression phrase ⇒ boolean An expression phrase that yield a boolean.
2 b expression phrase ⇒ boolean An expression phrase that yield a boolean.
Returns send phrase ⇒ boolean ab.
boolean, []→boolean
Source: /avail/Avail/Foundation/Logic
Categories: Logic
Compute and answer the joint denial, i.e., NOR, of the arguments. This is equivalent to ¬({@param a } ∨ b ). Short-circuit the computation, i.e., only evaluate b if a is false.
Position Name Type Description
Parameters
1 a boolean
2 b []→boolean
Returns boolean

#### Semantic restrictions:

false's type's type, []→(false's type)'s type
Source: /avail/Avail/Foundation/Logic
If the left-hand argument of _↓_ is known statically to be false, then the static type of the expression is the negation of b 's return type.
Type Description
Parameter Types
false's type's type
[]→(false's type)'s type
false's type's type, []→(true's type)'s type
Source: /avail/Avail/Foundation/Logic
If the left-hand argument of _↓_ is known statically to be false, then the static type of the expression is the negation of b 's return type.
Type Description
Parameter Types
false's type's type
[]→(true's type)'s type
boolean's type, []→(true's type)'s type
Source: /avail/Avail/Foundation/Logic
If the right-hand argument of _↓_ is known statically to be false, then the static type of the expression is false.
Type Description
Parameter Types
boolean's type
[]→(true's type)'s type
true's type's type, []→boolean's type
Source: /avail/Avail/Foundation/Logic
If the left-hand argument of _↓_ is known statically to be true, then the expression is known statically to be false.
Type Description
Parameter Types
true's type's type
[]→boolean's type