nice_things/type/class.sh

Utility functions for implementing classes. This module is automatically imported by the class macro for use in the default private methods.

check_reference

Since 0.3.0 · Source

import "{ check_reference }" from nice_things/type/class.sh

Synopsis
check_reference <ref> [<caller_name>]

Configuration
–

Description
Check if <ref> looks like a reference to an object; abort on failure.

An optional second argument <caller_name> can be used to pass in the name of the calling function, to improve the error message.

Note

This function is used internally by all the default private methods of a class. Calling it directly is rarely necessary because most public methods will start by calling their private getter <Class>_get_, in which case the reference has already been checked.

Options
–

Operands

• <ref>: The value to check.
• <caller_name>: Optional name of the calling function.

Stdin
–

Stdout
–

Stderr
log_error.

Exit status

• 0: Successful completion.
• 12: Invalid reference (abort).

Abort
Aborts on invalid reference.

Usage examples

NS__MyClass_method() {
	check_reference "$1" MyClass_method
	# Do something with "$1"
}

get_instance_id

Since 0.3.0 · Source

import "{ get_instance_id }" from nice_things/type/class.sh

Synopsis
get_instance_id <ref> <out_var>

Configuration
–

Description
Get the instance id part of an object reference and assign it to a variable. The instance id is a unique identifier of the object instance and can be used as a portion of a variable name, as long as not the beginning of the name. This can be used to create object state.

Note

This is a low-level function used internally by the default private methods of a class. User code will rarely need this.

Options
–

Operands

• <ref>: An object reference.
• <out_var>: Output variable; the result will be written to this variable.

Stdin
–

Stdout
–

Stderr
–

Exit status
0: Successful completion.

Abort
–

Usage examples

NS__MyClass_method() {
	check_reference "$1" MyClass_method
	get_instance_id "$1" NS__instance_id
	# Do something with "$NS__instance_id"
}