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dum

Translation status: العربية reader-locale proof. Code fences render through the ar pipeline; prose is canonical Latin.

Repeats a block while a condition remains true.

Aliases: while

Syntax: dum <condition> <block|ergo statement>

Category#

control-flow

Examples#

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

Repeats a block while a condition remains true.

# =============================================================================
# dum — Repeats a block while a condition remains true.
# =============================================================================
#
# What this teaches:
#   • While loop — `dum <condition> { <body> }` repeats a block as long as the condition is true.
#   • Loop variable mutation — mutable `varia` bindings allow counter-based loop control.
#   • Ascending and descending loops — counting up from 0 or down from N until the condition is falsum.
#
# Common mistakes:
#   • Using `rumpe` or `perge` outside a loop — both are only valid inside `dum`, `itera`, `fac`, `meus`, or `tuus` blocks (SEM030, SEM031).
#
# See also: si, ergo, fac
# =============================================================================

# dum — while loop
#
# dum <condition> { <body> }
#
# GRAMMAR:
#   loopStmt :← 'dum' expr '{' stmt* '}'
#
# EXPECTED OUTPUT:
#   dum.expected

main {
    # Ascending counter: varia so the loop variable can mutate
    var int computus ← 0

    while computus < 5 {
        print computus
        computus ← computus + 1
    }

    # Descending loop: condition becomes falsum at 0
    var int reliquum ← 3

    while reliquum > 0 {
        print "reliquum: §"(reliquum)
        reliquum ← reliquum - 1
    }

    print "perfectum!"
}

test "dum counts up to its condition" {
    var int computus ← 0
    while computus < 5 {
        computus ← computus + 1
    }
    assert computus ≡ 5
}

test "dum counts down to zero" {
    var int reliquum ← 3
    while reliquum > 0 {
        reliquum ← reliquum - 1
    }
    assert reliquum ≡ 0
}

Expected output:

0
1
2
3
4
reliquum: 3
reliquum: 2
reliquum: 1
perfectum!