Level: novices, n00bs
Rust is a statically typed language, which helps preventing runtime bugs, and ensures memory safety at compile time, that is with no runtime costs. However, sometimes one may need using dynamic values. Also, Rust doesn't support "out of the box" complex static structures, which still can be solved with some lazy initialization tricks.
Below are some notes on dynamic data types, and global static objects in Rust programming language.
| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <title>Wasm</title> | |
| </head> | |
| <body> | |
| <script> | |
| (async () => { | |
| /** |
| /** | |
| * Calculator grammar to generate parser in Rust. | |
| */ | |
| %lex | |
| %% | |
| // ----------------------------------------------- | |
| // Lexical grammar. |
| extern crate syntax; | |
| use syntax::Parser; | |
| fn main() { | |
| let mut parser = Parser::new(); | |
| let result = parser.parse("2 + 2 * 2"); | |
| println!("{:?}", result); // 6 | |
| } |
| /** | |
| * JavaScript static scope example. | |
| */ | |
| const x = 10; | |
| function print_x() { | |
| console.log(x); | |
| } |
| # Perl example of static and dynamic scopes | |
| $x = 10; | |
| sub print_x { | |
| print $x; | |
| } | |
| sub static { | |
| my $x = 20; # doesn't affect |
| /** | |
| * JavaScript dynamic `this` value. | |
| */ | |
| function produce() { | |
| console.log(this.x); | |
| } | |
| const alpha = {produce, x: 1}; | |
| const beta = {produce, x: 2}; |
| /** | |
| * JavaScript runtime-augmented scope example. | |
| */ | |
| let x = 10; | |
| let o = {x: 30}; | |
| let storage = {}; | |
| (function foo(flag) { |
| /** | |
| * NFA (Non-deterministic finite automata) | |
| * | |
| * A formalism for regular grammars (to recognize strings based on regular | |
| * expressions). | |
| * | |
| * Regexp parser to transform AST to NFA: | |
| * https://www.npmjs.com/package/regexp-tree | |
| * | |
| * NFA/DFA fragment examples: |