Type Functions

Type Functions

Type functions perform operations that check or convert expressions.

Type-Checking Functions

ISARRAY(expression)

Returns True if expression is an array, otherwise returns MISSING, NULL or false.

ISATOM(expression)

Returns True if expression is a Boolean, number, or string, otherwise returns MISSING, NULL or false.

ISBOOLEAN(expression)

Returns True if expression is a Boolean, otherwise returns MISSING, NULL or false.

ISNUMBER(expression)

Returns True if expression is a number, otherwise returns MISSING, NULL or false.

ISOBJECT(expression)

Returns True if expression is an object, otherwise returns MISSING, NULL or false.

ISSTRING(expression)

Returns True if expression is a string, otherwise returns MISSING, NULL or false.

TYPE(expression)

Returns one of the following strings, based on the value of expression:

  • "missing"
  • "null"
  • "boolean"
  • "number"
  • "string"
  • "array"
  • "object"
  • "binary"

Type-Conversion Functions

TOARRAY(expression)

Returns array as follows:

  • MISSING is MISSING.
  • NULL is NULL.
  • Arrays are themselves.
  • All other values are wrapped in an array.

TOATOM(expression)

Returns atomic value as follows:

  • MISSING is MISSING.
  • NULL is NULL.
  • Arrays of length 1 are the result of TOATOM() on their single element.
  • Objects of length 1 are the result of TOATOM() on their single value.
  • Booleans, numbers, and strings are themselves.
  • All other values are NULL.

TOBOOLEAN(expression)

Returns Boolean as follows:

  • MISSING is MISSING.
  • NULL is NULL.
  • False is false.
  • Numbers +0, -0, and NaN are false.
  • Empty strings, arrays, and objects are false.
  • All other values are true.

TONUMBER(expression)

Returns number as follows:

  • MISSING is MISSING.
  • NULL is NULL.
  • False is 0.
  • True is 1.
  • Numbers are themselves.
  • Strings that parse as numbers are those numbers.
  • All other values are NULL.

TOOBJECT(expression)

Returns object as follows:

  • MISSING is MISSING.
  • NULL is NULL.
  • Objects are themselves.
  • All other values are the empty object.

TOSTRING(expression)

Returns string as follows:

  • MISSING is MISSING.
  • NULL is NULL.
  • False is "false".
  • True is "true".
  • Numbers are their string representation.
  • Strings are themselves.
  • All other values are NULL.