reluxscript 0.1.4

Write AST transformations once. Compile to Babel, SWC, and beyond.
Documentation 
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/**
 * Test: Arrow Function Syntax (=>)
 *
 * C# developers write:
 *   list.Select(x => x.Name)
 *
 * Instead of Rust-style:
 *   list.iter().map(|x| x.name)
 */
plugin ArrowFunctions {

    struct State {
        result: Str,
    }

    fn init() -> State {
        State { result: "" }
    }

    pub fn visit_array_expression(node: &ArrayExpression) {
        let items = vec!["a", "b", "c"];

        // Single parameter arrow function
        let mapped = items.iter().map(x => x.to_uppercase());

        // Multiple parameters (parentheses required)
        let pairs = vec![(1, 2), (3, 4)];
        let sums = pairs.iter().map((a, b) => a + b);

        // Arrow with block body
        let processed = items.iter().map(x => {
            let upper = x.to_uppercase();
            format!("[{}]", upper)
        });

        // Nested arrows
        let matrix = vec![vec![1, 2], vec![3, 4]];
        let flattened = matrix.iter().flat_map(row => row.iter().map(x => x * 2));

        // Filter with arrow
        let filtered = items.iter().filter(x => x.len() > 1);

        // Any/All with arrow
        let has_long = items.iter().any(x => x.len() > 2);
        let all_short = items.iter().all(x => x.len() < 10);
    }

    fn finish() -> Str {
        self.state.result
    }
}