Conversion and Parsing

Coerce between value kinds.

to_number

• Signature: Any -> Number | null
• Behavior: Coerce to number. "42" → 42, "3.14" → 3.14, true → 1, false → 0. Returns null for unparseable strings.

QUERY:  "42".to_number()     OUT: 42
QUERY:  "3.14".to_number()     OUT: 3.14
QUERY:  "abc".to_number()      OUT: null

to_bool

• Signature: Any -> Boolean
• Behavior: Truthiness: false/null/0/""/[]/{} → false, everything else → true.

QUERY:  $.maybe.to_bool()

parse_int(radix?)

• Signature: String -> Number | null
• Behavior: Parse a string as integer, optional radix (default 10).

QUERY:  "42".parse_int()     OUT: 42
QUERY:  "ff".parse_int(16)     OUT: 255
QUERY:  "0b101".parse_int(2)     OUT: 5

parse_float

• Signature: String -> Number | null
• Behavior: Parse a string as float (IEEE 754 double).

QUERY:  "3.14".parse_float()     OUT: 3.14
QUERY:  "1e6".parse_float()     OUT: 1000000.0

parse_bool

• Signature: String -> Boolean | null
• Behavior: Strict parse: only "true" and "false" (lowercase) match; everything else returns null.

QUERY:  "true".parse_bool()     OUT: true
QUERY:  "TRUE".parse_bool()     OUT: true

as cast (operator)

The as operator does the same coercions as to_*:

"42" as int          # 42
42 as string         # "42"
true as int          # 1

Use as when the type is statically known; use to_number/parse_* when parsing untrusted strings (since as errors on failure rather than returning null).

Round-trip JSON

For full document round-trip, see from_json/to_json.

Practical examples

# Coerce strings collected from a CSV
$.rows.map(r => r.merge({age: r.age.to_number(), price: r.price.parse_float()}))

# Defensive parse — null on garbage
$.user_input.parse_int() ?? 0

# Boolean coercion of a flag string
"true".parse_bool() ?? false

# Truthiness coercion
$.value.to_bool()               # null/0/""/empty → false; else true

# Cast operator for static conversions
($.id as string).pad_left(8, "0")

# Round-trip number → string → back
(3.14 as string).parse_float()  # → 3.14