let

Declares an inferred immutable local.

Syntax: let <name> [← <expression>]

Category#

binding

Related#

• const
• var
• ←

Examples#

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

Declares an inferred immutable local.

# =============================================================================
# let — Declares an inferred immutable local.
# =============================================================================
#
# What this teaches:
#   • Immutable binding sugar — `let name` is a compact alternative to
#     `const _ name` for inferred-type immutable locals
#   • Supports immediate init (`let x ← expr`) and deferred init
#     (`let x` then `x ← expr` later)
#
# Common mistakes:
#   • Confusing `let` (sugar for `const _`) with `var` — `let` creates an immutable binding.
#
# See also: const, var, ←
# =============================================================================



# let — inferred immutable bindings
#
# Immediate init:
#   let name ← expr        -- compact sugar for const _ name ← expr
#
# Deferred init:
#   let name               -- compact sugar for const _ name (assign once later)
#   name ← expr
#
# Prefer let when a block chains several inferred locals; keep const _ when
# teaching the explicit infer marker or mixing typed and inferred bindings.
#
# GRAMMAR:
#   sitDecl := 'let' IDENTIFIER ('←' expression)?
#
# EXPECTED OUTPUT:
#   sit.expected

main {
    let salve ← "Salve"
    let name ← "Marcus"
    let nuntius ← "§, §!"(salve, name)

    print nuntius

    let label
    label ← "deferred"
    print label

    const _ idem ← nuntius
    print idem
}

Expected output:

Salve, Marcus!
deferred
Salve, Marcus!