Aladino semantics

Aladino supports five types of values: booleans, numbers, strings, arrays and a special type _action_.

Since the language is quite simple, it is also straightforward to perform type inference.

There are two requirements when it comes to typing:

1. The type of the expression in a rule spec is bool. For example, the following rule is invalid:

- name: doesnt-type-check-to-bool
  kind: patch
  description: Rule that does not type check to bool
  spec: "hello" # type error

2. The type of each action to be effect. For example, the following workflow is invalid because of its actions:

- name: invalid-workflow
  description: Invalid workflow because of action
  if:
      - rule: rule_1
  then:
      - "hello" # type error

Since, by design, you cannot define functions or variables, the usefulness of the language comes down to the set of built-in variables and functions that are provided.