Literals

This page lists the literal forms used in Lutra expressions.

Boolean literals¶

Boolean literals are true and false.

true
false

Text literals use double quotes.

"hello"
"I don't like it"

Interpolated text literals start with f and can embed expressions in {}.

f"Hello {name}"
f"Come here {dog_name}"

Integer literals are written in decimal by default. You can add a type with : Type when the surrounding context does not already fix the type.

1
432
-23
1: int32
18446744073709551615: uint64

Hexadecimal integer literals use the 0x prefix.

0x7f: int8
0xffff: uint16
0x7fffffffffffffff: int64

Underscores are allowed as visual separators.

3_112_212_123_123_123

Floating-point literals use a decimal point.

42.801
-32.2
1.10: float32
-1121121221.0: float64

When annotated withstd::Decimal, numeric literals are interpreted as std::Decimal values.

func main(): [std::Decimal] -> [
  4.2,
  4.20,
  4.02,
  3_112_212_123_123_123.11,
]

std::Decimal preserves the fixed-scale decimal representation used by the value, so 4.2 is printed as 4.20.

Date literals start with @ and use year-month-day.

@2025-11-14
@-10000-11-14
@+100000-11-14

These literals have type std::Date.

Time literals also start with @ and use hour:minute:second, with an optional fractional part.

@16:07:44.123456
@16:07:44.12
@213:06:00
@-5:12:31.12

These literals have type std::Time.

Timestamp literals combine a date and a time with T.

@2025-12-29T16:07:44.123456
@2025-12-29T16:07:44.12

These literals have type std::Timestamp.

Tuple, array, and enum construction use expression syntax rather than literal syntax. See Expressions.