Add a new service checklist

• according to ttsService.h
• implement TextToSpeechService::speak
• implement TextToSpeechConfigWidget::save
• DONE.

Design

TL;DR: Simply do nothing, avoid almost all temptation to do 💩 abstraction 💩 unless absolutely necessary.

Goals:

• Make adding new services easy.
• Allow modifying / evolving any one of the services arbitrarily without incurring the need to touch another.

Code:

• Config file deserialization and Service state mutating won't exist in parallel.
• Service construct only based on config file. One single deterministic routine.

(1) Service configure GUI --write--> (2) Service's config file --create--> (3) Live Service Object

(1) will neither mutate nor access (3).

construct (3) only according to (2).

(1) only write to (2).

• Service construction will be done on the consumer side to avoid sharing constructor
• Service can be cast to Service, which only has speak and destructor, since the consumer should not care anything else after construction.
• Services don't share global config, don't share config mechanisms.
• Does not assume services have any similarity other than the fact they may speak.
• Avoid any "abstraction" across services.

Rational:

• Services are different.
• Construction materials needed by services are different.
• Services on earth are limited, thus the boilerplate caused by fewer useless abstractions is also limited
• The consumer will use services incredibly creative in the future.
• Abstracting seemingly similar but different things will eventually blunder.