nihil

Represents the null value and can prefix a null check.

Syntax: nihil [<expression>]

Category#

literal

Related#

• ∪
• sponte
• nihil

Examples#

radix/corpus/literalia/nihil.fab (canonical · keyword)#

Null literal and nullable union bindings.

# =============================================================================
# nihil — Null literal and nullable union bindings.
# =============================================================================
#
# What this teaches:
#   • the `nihil` literal — represents absence of a value (null)
#   • nullable union types with `∪` — `T ∪ nihil` for values that may be absent
#   • null checks with `est nihil` and `non est nihil`
#
# Common mistakes:
#   • Using nihil without declaring the type as T ∪ nihil — nihil requires a nullable union type.
#
# See also: ∪, sponte, nihil
# =============================================================================

# literalia/nihil — nihil literal and T ∪ nihil
#
# GRAMMAR:
#   literal :← 'nihil'
#   unionType :← type '∪' 'nihil'
#
# EXPECTED OUTPUT:
#   nihil, verum, 42
#
# BACKEND:
#   Cross-ref nihil/nihil.fab.

fn maybe() → int ∪ null {
    return 42
}

main {
    const int ∪ null absent ← null
    print absent

    const _ nihilne ← absent is null
    print nihilne

    print maybe() not is null
}

Expected output:

nihil
verum
verum

radix/corpus/nihil/nihil.fab (canonical · keyword)#

Represents the null value and can prefix a null check.

# =============================================================================
# nihil — Represents the null value and can prefix a null check.
# =============================================================================
#
# What this teaches:
#   • the `nihil` keyword — used for null/none values
#
# Common mistakes:
#   • Using nihil without ∪ in the type position — nullable types must be declared as T ∪ nihil.
#
# See also: ∪, sponte
# =============================================================================

# nihil — null literal
#
# GRAMMAR:
#   literal :← 'nihil'
#
# EXPECTED OUTPUT:
#   Scalar stdout smoke (see body).
#

main {
    const _ nothing ← null
    print nothing
}

Expected output:

nihil