分支

Introduces a branch inside an 選擇 or 比對 statement.

Aliases: case

Syntax: 分支 <expression> <block>

Category#

control-flow

Related#

• 選擇
• 比對

Examples#

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

Introduces a branch inside an 選擇 or 比對 statement.

# =============================================================================
# 分支 — Introduces a branch inside an 選擇 or 比對 statement.
# =============================================================================
#
# What this teaches:
#   • Pattern matching arms — `分支 <expression> <block>` defines a branch in
#     an `選擇` match expression
#   • Default fallback — `預設` provides the catch-all branch when no
#     `分支` pattern matches
#
# Common mistakes:
#   • non-exhaustive match without a `預設` catchall — every `選擇` or `比對` must cover all possibilities or add a `預設` arm
#
# See also: 選擇, 比對
# =============================================================================

# 分支 — branch arm in 選擇 or 比對
#
# GRAMMAR:
#   casuClause :← '分支' expr block
#
# EXPECTED OUTPUT:
#   Scalar stdout smoke (see body).
#
# BACKEND:
#   Cross-ref: 選擇/elige.fab, 比對/discerne.fab.
#

main {
    const _ code ← 200
    switch code {
        case 200 {
            print "ok"
        }
        default {
            print "other"
        }
    }
}

Expected output:

ok