Programming

正交（orthogonal）

operations change just one thing without affecting others.
编程中。正交指互相独立，不可替代，并且可以任意组合。

耦合（Coupling）

the degree of interdependence between software modules.
模块间的独立性。

内聚（Cohesion）

the degree to which the elements inside a module belong together.
模块是否向着某一统一目的而组合在一起。

原语（Primitives）

https://en.wikipedia.org/wiki/Language_primitive
In computing, language primitives are the simplest elements available in a programming language. A primitive is the smallest ‘unit of processing’ available to a programmer of a given machine, or can be an atomic element of an expression) in a language.
程序语言处理最小单元

GUI & TUI & CLI

GUI Graphic User Interface： 图形用户界面。为命令提供的带窗口和下拉菜单的用户界面
TUI Terminal User Interface/Text User Interface： 终端用户界面/ 文本用户界面。适用于 ASCII 终端的带窗口和下拉菜单的基于字符的显示。TUI 使用键盘导航（不支持鼠标）。
CLI(CLUI) Command Line (User) Interface： 命令行(用户)界面。在命令行提示符处输入的或由脚本执行的文本格式的命令和选项

Rust

Rust要求表达式返回类型一致，Rust 一切皆表达式；
if else 也是一种表达式，所以 if else 分支返回的类型也就得一致；
Rust 之所以要求函数不能返回多种类型是因为 Rust 在需要在 编译期确定返回值占用的内存大小, 显然不同类型的返回值其内存大小不一定相同.

Scalar Types

• signed integers: i8, i16, i32, i64, i128 and isize (pointer size)
• unsigned integers: u8, u16, u32, u64, u128 and usize (pointer size)
• floating point: f32, f64
• char Unicode scalar values like 'a', 'α' and '∞' (4 bytes each)
• bool either true or false
• and the unit type (), whose only possible value is an empty tuple: ()

Despite the value of a unit type being a tuple, it is not considered a compound type because it does not contain multiple values.

Compound Types

• arrays like [1, 2, 3]
• tuples like (1, true)

Variables can always be type annotated. Numbers may additionally be annotated via a suffix or by default. Integers default to i32 and floats to f64. Note that Rust can also infer types from context.