#05. Collection types

Now let's add the two collection forms.

#Start the demo server

telepact demo-server --port 8000

#The collection type expressions

Type expression	Meaning
`["string"]`	array of strings
`{"string": "number"}`	object whose keys are strings and whose values are numbers

That object key is always string, because JSON object keys are strings.

#Where they show up in the demo schema

{
  "fn.deleteVariables": {
    "names": ["string"]
  },
  "fn.saveVariables": {
    "variables": {"string": "number"}
  }
}

#Real examples

#Array

curl -s localhost:8000/api -d '[{}, {"fn.deleteVariables": {"names": ["a", "b"]}}]'

[{}, {"Ok_": {}}]

#Object

curl -s localhost:8000/api -d '[{}, {"fn.saveVariables": {"variables": {"a": 2, "b": 4}}}]'

[{}, {"Ok_": {}}]

#Empty collections are already expressive

Both of these are still valid:

curl -s localhost:8000/api -d '[{}, {"fn.deleteVariables": {"names": []}}]'
curl -s localhost:8000/api -d '[{}, {"fn.saveVariables": {"variables": {}}}]'

That is why Telepact does not try to express nullable collections like []? or {}?. Emptiness already has a natural representation.

Next: 06. Structs