Conditionals

A conditional shows content only when the data agrees — order states, draft banners, sale prices. Statements sit in parentheses, so logic reads as an aside.

Compare with is

#order: { status: shipped, items: 3 } !!

(if @order.status is shipped)
Your order is on its way.
(else)
We are packing your order.
(end)

<p>Your order is on its way.</p>

is is the only operator; the right side is a value. There is no not, and, or, < or contains — a header other than (if @path …) is E_MALFORMED_STATEMENT. Numbers compare by value, so (if @order.items is 3) matches.

Test truthiness

Drop is to test whether a value is present and truthy. Falsy is: missing, empty, false, null, 0, an empty record and an empty collection. Everything else is truthy. Simple definitions can be tested too.

#gift: false !!
#order: { items: 3 } !!

(if @order.items)Three items. (end)(if @gift)Gift-wrapped. (end)Thanks!

That renders Three items. Thanks!

Else and nesting

(else) is optional, either branch may be empty, and ifs nest, each with its own (end):

#lamp: { lit: true, oil: low } !!

(if @lamp.lit)
(if @lamp.oil is low)
Lit, but refill the oil tonight.
(else)
Lit and fuelled.
(end)
(end)

That renders Lit, but refill the oil tonight.

Inside a definition

Test a parameter with (if ::name::):

#price(amount, sale)
£::amount::(if ::sale::) (on sale)(end)
price#

Soup @price(amount: 12, sale: true), bread @price(amount: 9, sale: false).

That renders Soup £12 (on sale), bread £9. A definition cannot sit inside a conditional — E_CONDITIONAL_DEFINITION — so put the condition inside the definition, as here.

Inline statements

Written inside a sentence, a statement stays inline. It may follow a space, punctuation, a reference or another statement's ), and its (else) and (end) may touch a word: (if @x)Done(end).

Errors

• E_UNCLOSED_STATEMENT — no (end).
• E_MALFORMED_STATEMENT — an operator other than is, or a subject that is not @path.
• E_CONDITIONAL_DEFINITION — a definition inside a branch.

See also

Iteration · Data · Faceted content · Gotchas