Types

MistQL has 8 core datatypes, many of which correspond to their JSON counterparts.

External types are types that can be either provided or returned by a MistQL query. All other types are considered internal and cannot be provided to or returned from MistQL.

Type	Primitive	External	Comment
string	✔	✔	Series of unicode codepoints
number	✔	✔	Doubles, without NaN or infinity
boolean	✔	✔
null	✔	✔
object		✔	Stringly typed keys
array		✔	Can be nonhomogenous
function			Arity not part of type system
regex

Type Equality

Equality in MistQL is strict, meaning that if two variables have different data types, they are considered unequal.

Type	Equality
string	exact
number	IEEE 754 compliant
boolean	exact
null	true
object	Deep equality
array	Deep equality
function	Referential
regex	On source and flag

Casting Tables

MistQL defines casting from some types to other types

Type	Cast to Float	Cast To String	Truthiness
string	Parsed as float, as per JSON standard.	noop	false if empty, true otherwise
number	noop	As base 10 float. If number is an integer, no trailing digits or decimal. Exponential notation when not within non-inclusive range 1e-7 to 1e21	IEEE 754 compliant
boolean	1 for true, 0 for false	"true" for true, "false" for false	Standard
null	0	"null"	false
object	Invalid Operation	Concise JSON, recursively converting items	false if empty, true otherwise
array	Invalid Operation	Concise JSON, recursively converting items	false if empty, true otherwise
function	Invalid Operation	Invalid Operation	true
regex	Invalid Operation	Invalid Operation	true

Type Properties

There are 3 properties that any given type may or may not exhibit. The properties are as follows:

• Comparable: Whether or not a type can be compared to another of the same type.
• NumberCastable: Whether or not a type can be cast to the number type.
• StringCastable: Whether or not a type can be cast to the string type.

The table for which types exhibit which properties can be seen below:

Type	Comparable	NumberCastable	StringCastable
string	✔	✔	✔
number	✔	✔	✔
boolean	✔	✔	✔
null	✔	✔	✔
object			✔
array			✔
function
regex