assert_defined and assert_undefined interfaces

This page explains the assert_defined and assert_undefined function interfaces.

What interfaces are these?

The assert_defined function interface asserts specified value is defined (initialized). Conversely, the assert_undefined function interface asserts specified value is undefined (not initialized or deleted).

See also

Basic usage

Both of the assert_defined and assert_undefined interfaces requires value argument and msg argument is optional.

The following assertion example (assert_defined and initialized value) passes:

import apysc as ap

stage: ap.Stage = ap.Stage(
    stage_width=0,
    stage_height=0,
    background_color=ap.Color("#333"),
    stage_elem_id="stage",
)

int_val: ap.Int = ap.Int(10)
ap.assert_defined(value=int_val, msg="Value is not defined!")

ap.save_overall_html(dest_dir_path="assert_defined_basic_usage_1/")

[assert_defined]
Right-side variable name: i_11
Left value: other than undefined right value: 10

The following assertion example (assert_defined and the deleted value) fails:

import apysc as ap

stage: ap.Stage = ap.Stage(
    stage_width=0,
    stage_height=0,
    background_color=ap.Color("#333"),
    stage_elem_id="stage",
)

int_val: ap.Int = ap.Int(10)
ap.append_js_expression(expression=f"{int_val.variable_name} = undefined;")
ap.assert_defined(value=int_val, msg="Value is not defined!")

ap.save_overall_html(dest_dir_path="assert_defined_basic_usage_2/")

[assert_defined]
Right-side variable name: i_11
Left value: other than undefined right value: undefined
...
Assertion failed: Value is not defined!

The following assertion example (assert_undefined and the deleted value) passes:

import apysc as ap

stage: ap.Stage = ap.Stage(
    stage_width=0,
    stage_height=0,
    background_color=ap.Color("#333"),
    stage_elem_id="stage",
)

int_val: ap.Int = ap.Int(10)
ap.append_js_expression(expression=f"{int_val.variable_name} = undefined;")
ap.assert_undefined(value=int_val, msg="Value is defined!")

ap.save_overall_html(dest_dir_path="assert_undefined_basic_usage_1/")

[assert_undefined]
Right-side variable name: i_11
Left value: undefined right value: undefined

assert_defined API

Note: the document build script generates and updates this API document section automatically. Maybe this section is duplicated compared with previous sections.

[Interface signature] assert_defined(value: Any, *, msg: str = '') -> None

[Interface summary]

JavaScript assertion interface for the defined (not undefined) value condition.

[Parameters]

  • value: *

    • Target value to check.

  • msg: str, optional

    • Message to display when assertion failed.

[Examples]

>>> import apysc as ap
>>> int_val: ap.Int = ap.Int(10)
>>> ap.assert_defined(int_val)

assert_undefined API

Note: the document build script generates and updates this API document section automatically. Maybe this section is duplicated compared with previous sections.

[Interface signature] assert_undefined(value: Any, *, msg: str = '') -> None

[Interface summary]

JavaScript assertion interface for the undefined value condition.

[Parameters]

  • value: *

    • Target value to check.

  • msg: str, optional

    • Message to display when assertion failed.

[Examples]

>>> import apysc as ap
>>> int_val: ap.Int = ap.Int(10)
>>> ap.append_js_expression(expression=f"{int_val.variable_name} = undefined;")
>>> ap.assert_undefined(int_val)