Refinement Types

Refinement Types🔗

TYML lets you add additional constraints to types.

port: int @value 100..<200

@value Attribute🔗

Available for numeric types: int, uint, or float.

setting: int @value 0..<100

You can specify ranges like 0..<100. The forms are:

• start..<end: start inclusive, end exclusive
• start..=end: start inclusive, end inclusive
• start..: start inclusive, no upper bound
• ..<end: end exclusive, no lower bound
• ..=end: end inclusive, no lower bound

@length Attribute🔗

Restrict the number of Unicode characters of a string.

setting: string @length 0..<100

Range notation is the same as for @value.

@u8size Attribute🔗

Restrict the UTF‑8 byte length of a string.

setting: string @u8size 0..<100

Range notation is the same as for @value.

@regex Attribute🔗

Restrict a string by a regular expression.

// Single quotes avoid escaping
setting: string @regex '^\\d+$'

Multiple Conditions🔗

Use and and or to combine constraints.

// "and" has higher precedence.
// Use () to adjust precedence.
setting: string (@length 0..<10 or @length 100..<200) and @regex '^\\d+$'