Syntax

Operators

Precedence ladder from primary expressions to conditionals

Notch parses expressions in a precedence ladder. The lower the number, the tighter the binding.

Precedence table

Precedence Operators
expr(0) int, boolean, string, ident, parens, list, map
expr(10) call, index
expr(20) negate, inverse
expr(30) multiplication, division, remainder
expr(40) addition, subtraction
expr(50) less, greater, lessequal, greaterequal
expr(60) equality
expr(70) logical and
expr(80) logical or
expr(90) fallback
expr(100) conditional

Custom operators

Notch has two operators that are not built from a single token.

Fallback

expr ?: expr

The fallback operator evaluates the left-hand side; if the result is null or undefined, it evaluates the right-hand side.

Conditional

expr if expr [else expr]

The conditional expression evaluates the second expression as a predicate. If it is true, the first expression is returned. If it is false and an else branch is present, the third expression is returned. If no else branch is given and the predicate is false, the result is undefined.

Emptiness

expr is empty
expr is not empty

Tests whether a value is empty. Empty means: an empty string, an empty list, an empty map, or null.

"" is empty           # true
[1] is not empty      # true
null is empty         # true

See also