unarius

Unary negation, logical not, sign comparisons, and optional presence tests.

Syntax: -<expr> | non <expr> | <expr> > 0 | <expr> est nihil

Category#

operators

Related#

• non
• est
• non est

Examples#

radix/corpus/unarius/unarius.fab (canonical · operator-group)#

Unary negation, logical not, sign comparisons, and optional presence tests.

# =============================================================================
# unarius — Unary negation, logical not, sign comparisons, and optional presence tests.
# =============================================================================
#
# What this teaches:
#   • Unary operators — negation (`-`), logical not (`non`), and sign comparisons
#   • Null checks — `est nihil` and `non est nihil` for optional presence testing
#
# Common mistakes:
#   • confusing non (logical not, prefix) with - (numeric negation) or ¬ (the Unicode not sign)
#
# See also: non, est, non est
# =============================================================================




# unarius — negation, logical not, sign comparisons, and optional presence
#
# -<expr>  non <bivalens>  <expr> > 0  <expr> < 0
# <expr> est nihil   <expr> non est nihil
#
# GRAMMAR:
#   unaryExpr :← ('-' | 'non') expr
#
# EXPECTED OUTPUT:
#   unarius.expected — unary operator samples.

main {
    # Numeric negation
    const _ x ← 5
    const _ neg ← -x
    # -5
    print neg

    # Logical negation
    const _ flag ← true
    const _ non_signum ← not flag
    # falsum
    print non_signum

    # Positive/negative checks
    const _ a ← 10
    const _ b ← -3
    # verum
    print a > 0
    # falsum
    print a < 0
    # falsum
    print b > 0
    # verum
    print b < 0

    # Null checks
    const string ∪ null forsitan ← null
    # verum
    print forsitan is null
    # falsum
    print forsitan not is null

    const string ∪ null adest ← "salve"
    # falsum
    print adest is null
    # verum
    print adest not is null
}

Expected output:

-5
falsum
verum
falsum
falsum
verum
verum
falsum
falsum
verum