Converts this Value into a boolean value, if possible; otherwise
returns undefined if this Value can't be converted into a boolean
value.
Converts this Value into a boolean value, if possible; otherwise
returns orElse if this Value can't be converted into a boolean value.
Returns the sole member of this Record, if this Record has exactly one
member, and its member is a Value; returns Extant if this Record
is empty; otherwise returns this if this Record has more than one
member.
Used to convert a unary Record into its member Value. Facilitates
writing code that treats a unary Record equivalently to a bare Value.
Returns the first member of this Record, if this Record is non-empty;
otherwise returns Absent.
Returns the value of the first member of this Record, if the first
member is an Attr whose key string is equal to tag; otherwise
returns Absent if the first member of this Record is not an Attr,
or if the first member of this Record is an Attr whose key does not
equal the tag.
Used to conditionally get the value of the head Attr of a structure, if
and only if the key string of the head Attr is equal to the tag. Can
be used to check if a structure might conform to a nominal type named
tag, while simultaneously getting the value of the tag attribute.
Returns the unflattened header of
this Record. The headers of the tag attribute of a structure are
like the attributes of an XML element tag; through unlike an XML element,
tag attribute headers are not limited to string keys and values.
Returns true if this Value is not Absent.
Converts this Value into a number value, if possible; otherwise returns
undefined if this Value can't be converted into a number value.
Converts this Value into a number value, if possible; otherwise returns
orElse if this Value can't be converted into a number value.
Returns the key string of the first member of this Record, if the
first member is an Attr; otherwise returns undefined if the first
member is not an Attr.
Used to concisely get the name of the discriminating attribute of a
structure. The tag can be used to discern the nominal type of a
polymorphic structure, similar to an XML element tag.
Returns a view of all but the first member of this Record, if this
Record is non-empty; otherwise returns an empty Record, if this
Record is itself empty.
Returns the flattened members of this Record after
all attributes have been removed.
Used to concisely get the scalar value of an attributed structure. An
attributed structure is a Record with one or more attributes that modify
one or more other members.
Always returns this because every Value is its own value component.
Returns this `Record.
Always returns Absent because a
Valuecan't be aField, so it can't have a key component.