Documentation

A value that can be stored in a Subject property record.

The Value type supports all gram notation value types, enabling property records to store rich, structured data. Values can be nested (arrays and maps can contain other values), enabling complex data structures.

Standard Types

Standard value types represent basic data:

• VInteger Integer - Integer numbers (e.g., 42, -10)
• VDecimal Double - Decimal numbers (e.g., 3.14, -0.5)
• VBoolean Bool - Boolean values (True or False)
• VString String - String literals (e.g., "hello")
• VSymbol String - Symbol identifiers (e.g., mySymbol)

Extended Types

Extended value types represent structured or qualified data:

• VTaggedString String String - Tagged strings with a type tag and content (e.g., url`https://example.com` becomes VTaggedString "url" "https://example.com")
• VArray [Value] - Arrays of values (e.g., [1, 2, 3])
• VMap (Map String Value) - Key-value maps (e.g., {key: "value"})
• VRange RangeValue - Numeric ranges (e.g., 1..10, 1..., ...10)
• VMeasurement String Double - Measurements with units (e.g., 5kg becomes VMeasurement "kg" 5.0)

Nested Values

Values can be nested to create complex structures:

>>> VArray [VString "a", VString "b", VString "c"]
>>> VMap (fromList [("nested", VArray [VInteger 1, VInteger 2])])

Examples

Creating values:

>>> VInteger 42
>>> VDecimal 3.14
>>> VBoolean True
>>> VString "hello"
>>> VSymbol "mySymbol"
>>> VTaggedString "url" "https://example.com"
>>> VArray [VInteger 1, VInteger 2, VInteger 3]
>>> VMap (fromList [("name", VString "Alice"), ("age", VInteger 30)])
>>> VRange (RangeValue (Just 1) (Just 10))
>>> VMeasurement "kg" 5.0

A range value representing numeric ranges.

Ranges can be: * Closed: both lower and upper bounds specified * Half-open: only lower or upper bound specified * Open: neither bound specified (represents all numbers)

Examples:

>>> RangeValue (Just 1) (Just 10)  -- 1..10 (closed range)
>>> RangeValue (Just 1) Nothing    -- 1... (lower bound only)
>>> RangeValue Nothing (Just 10)   -- ...10 (upper bound only)
>>> RangeValue Nothing Nothing      -- ... (all numbers)