75bc30bb8e
Implement parsing, evaluation, lexical this capture, and new rejection for arrow functions. Covers expression bodies, block bodies, zero/single/ multi-param forms, and backtracking disambiguation from grouping parens. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
28 lines
785 B
JavaScript
28 lines
785 B
JavaScript
// Arrow functions can read variables from their enclosing (outer) scope.
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// Reading a global variable defined before the arrow.
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var base = 10;
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var addBase = x => x + base;
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console.log(addBase(5));
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// Multiple arrows can share the same outer variable.
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var multiplier = 3;
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var triple = x => x * multiplier;
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var quadruple = x => x * 4;
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console.log(triple(7));
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console.log(quadruple(7));
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// Arrow reads a variable that was updated after the arrow was defined.
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var counter = 0;
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var getCounter = () => counter;
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counter = 99;
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console.log(getCounter());
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// Arrow passed to Array.forEach (using a hand-rolled loop) closes over outer variable.
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var sum = 0;
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var values = [1, 2, 3];
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for (var i = 0; i < values.length; i++) {
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(function(v) { sum = sum + v; })(values[i]);
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}
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console.log(sum);
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