record

record

An immutable set of key,value pairs. This is the core datastructure of the language.

In addition to the builtin messages defined in this module, records also respond to their keys as messages.

len

record.len: () => int

Return the number of key-value pairs in the record.

[1 2 3].len # => 3

at

record.at: unknown => (some (status ok:, value unknown) | none none:)

Check for a value at the given key.

Returns a tuple with the result of the check, and the value if it was found.

(ok value) = { name: 'John Doe' } .at (name:)

ok    # => ok:
value # => 'John Doe'

(ok value) = { name: 'John Doe' } .at (age:)

ok    # => none:
value # => nil:

put

record.put: (key unknown, value unknown) => record

Return a new record with the additional key-value pair, or an updated value for an existing key.

person = { name: 'John Doe' }

person = person.put(age: 30)

person.name # => 'John Doe'
person.age  # => 30

put_via

record.put_via: (key_path *unknown, value unknown) => record

Traverse nested records with the given key_path, eventually performing a final put.

person = {
  mother: = {
    name: 'Jane Doe' 
  }
}

person = person.put_via(mother: age: 60)

person.mother.age # => 60

This message will create records along the path where none exist.

{}.put_via(mother: sister: daugher: relation: 'cousin')

# => { mother: { sister: { daughter: { relation: 'cousin' } } } }

at_via

record.at_via: key_path *unknown => (some (status ok:, value unknown) | none none:)

Get a value by traversing nested maps with the given key_path. If any key along the path is missing, returns none:

(ok, value) = record.at_via(a: long: run: of: keys:)

put_by

record.put_by: (key unknown, f is\block:) => record

Apply a function to the value at key, returning a new record with the returned value from that function at key.

person = { age: 30 }

person = person.put_by(age: age => age + 1)

person.age # => 30

If the key does not exist in the record, then the argument to the block will be nil:.

put_via_by

record.put_via_by: (key_path *unknown, f is\block:) => record

Apply a function to the value at key_path, returning a new record with the returned value from that function at key_path.

Combines the behavior of put_via: and put_by:.

push

record.push: unknown => record

Return a new record with the given value at the end of the record. The key will be the length of the record before inserting.

arr = [1 2 3] .push 4

arr # => [1 2 3 4]

pop

record.pop: () => (some (status ok:, value (record record, popped_value unknown, popped_key unknown)) | none none:)

Return a new record without the last key-value pair in the record.

(ok rec val key) = [1 2 3 4].pop

ok  # => ok:
rec # => [1 2 3]
val # => 4
key # => 3

If the record was empty, returns none: and an empty record.

[].pop # => none: []

is\record

unknown.is\record: () => boolean

Returns true: if the receiver is a record, and false: otherwise.

keys

record.keys: () => List[unknown]

Return a list of all the keys in the record, in order.

vals

record.vals: () => List[unknown]

Return a list of all the values in the record, in order.

record.: unknown => unknown

Return the value at the key given by the argument. If the key doesn’t exist, panic.

map = { 'id' 1234 }

map.('id') # => 1234

map.('name') # => panic

This allows for records to serve as functions of their keys.