66 lines
1.9 KiB
Rust
66 lines
1.9 KiB
Rust
use std::collections::HashMap;
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#[derive(Debug, PartialEq, Eq)]
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pub enum Token {
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Identifier(String),
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Equal,
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Ampersand,
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Semicolon,
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}
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pub type Tokens = Vec<Token>;
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pub fn parse_key_value(text: &str) -> HashMap<String, String> {
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/* Parses foo=bar&baz=qux&zap=zazzle into respective hashmap. */
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let mut tokens: Tokens = vec![];
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let mut result = HashMap::new();
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tokens = scan(text, 0, tokens);
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for token_chunk in tokens.chunks(4) {
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match token_chunk {
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[Token::Identifier(key), Token::Equal, Token::Identifier(value), Token::Ampersand | Token::Semicolon]
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| [Token::Identifier(key), Token::Equal, Token::Identifier(value)] => {
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result.insert(key.to_string(), value.to_string());
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}
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_ => panic!("Could not parse {:?}", token_chunk),
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};
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}
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result
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}
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fn scan(code: &str, mut ix: usize, mut tokens: Tokens) -> Tokens {
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if ix == code.len() {
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return tokens;
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}
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let c: char = code[ix..].chars().next().unwrap();
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if c.is_ascii_alphanumeric() || SPECIAL_CHARS.contains(&c) {
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return scan_identifier(code, ix, tokens);
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}
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match c {
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'&' => tokens.push(Token::Ampersand),
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'=' => tokens.push(Token::Equal),
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';' => tokens.push(Token::Semicolon),
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_ => panic!("Unexpected char '{}' at index {}", c, ix),
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}
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ix += 1;
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scan(code, ix, tokens)
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}
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fn scan_identifier(code: &str, mut ix: usize, mut tokens: Tokens) -> Tokens {
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let start_ix = ix;
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let chars = code[ix..].chars();
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for c in chars {
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if c.is_ascii_alphanumeric() || SPECIAL_CHARS.contains(&c) {
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ix += 1;
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} else {
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break;
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}
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}
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let token = Token::Identifier(code[start_ix..ix].to_string());
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tokens.push(token);
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scan(code, ix, tokens)
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}
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const SPECIAL_CHARS: &[char] = &['.', '@', '%'];
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