do

Starts a scoped do-while style loop.

Aliases: do

Syntax: do <block> [catch <name> <block>] [while <condition>]

Category#

control-flow

Related#

• while
• catch
• lambda
• continue

Examples#

radix/corpus/fac/fac-cape.fab (canonical · keyword)#

Starts a scoped do-while style loop.

# =============================================================================
# do — Starts a scoped do-while style loop
# =============================================================================
#
# What this teaches:
#   • Starts a scoped do-while style loop.
#   • Related keywords: while, catch, lambda, continue
#
# Common mistakes:
#   • Using `catch` on a non-`do` block — `catch` only attaches to `do` statements, not arbitrary blocks.
#
# See also: while, catch, lambda, continue
# =============================================================================

# do — try block with catch error handler
#
# do { <body> }
# catch err { <handler> }
#
# GRAMMAR:
#   facStmt :← 'do' block 'catch' ident block
#
# EXPECTED OUTPUT:
#   none — success path then simulated failure on attempt 2
#
# BACKEND:
#   Rust/Go: do/cape not yet emitted — compile-only smoke.

main {
    do {
        print "Block executed successfully"
    }
    catch err {
        print "Caught error: §"(err.nuntius)
    }

    # throw on second attempt; catch recovers and prints err.nuntius
    var int attempts ← 0
    do {
        attempts ← attempts + 1
        print "Attempt §"(attempts)
        if attempts ≡ 2 {
            throw "Simulated failure"
        }
    }
    catch err {
        print "Failed on attempt §: §"(attempts, err.nuntius)
    }
}