Examples#

If branching#

If-branch logic can be comprehended as the c++ code:

if (condition) {
   // ...
}

The code shown below will execute the then part if the variable c is true. The then part only contains a function calling command which calls the print function to print variable a.

- if:
    condition:
      get: c
    then:
      - call:
          name: io::print
          params:
            - get: a

The structure of else is similar.

- if:
    condition:
      get: c
    then:
      - call:
          name: io::print
          params:
            - get: a
    else:
      - call:
          name: io::print
          params:
            - get: b

Define a Variable#

In Cablin, a variable should be defined before using it.

• Define an integer variable which name is a and the default value is 1.

- var:
    type: int
    name: a
    default_value: 1

• Define a string variable which name is b and the default value is Hello string

- var:
    type: string
    name: b
    default_value: Hello string

Assign a Variable with a Value#

• a = a + b:

The Cablin interpreter doesn't support infix expression currently. Instead, it provides a plus node. Input two values, and return their sum.

Hence, in the source, we use the plus node and get a + b.

- assign:
    target: a
    source:
      plus:
        - get: a
        - get: b

Scope#

When an expression tries to fetch the value of a variable. The interpreter will try to find in the most nearby scope.

- block:
    - var:
        name: a
        type: int
        default_value: 1
    - if:
        # The condition is a constant: true. Hence it will be always passed.
        condition:
            const:
                type: bool
                value: true

        # then is also a scope
        then:
            - var:
                name: a
                type: int
                deafult_value: 2
            - call:
                name: io::print
                params:
                    - get: a

The result of the print command is 2.