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Added initial ES7 transformer

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This commit is contained in:
Ron Buckton 2016-02-16 18:10:52 -08:00
parent 6c0551f867
commit 1ceb02a5bc
1 changed files with 67 additions and 2 deletions
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69
src/compiler/transformers/es7.ts
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@ -3,7 +3,6 @@
/*@internal*/
namespace ts {
// TODO(rbuckton): ES7->ES6 transformer
export function transformES7(context: TransformationContext) {
const { hoistVariableDeclaration } = context;
@ -26,7 +25,73 @@ namespace ts {
}
function visitorWorker(node: Node) {
return node;
switch (node.kind) {
case SyntaxKind.BinaryExpression:
return visitBinaryExpression(<BinaryExpression>node);
}
Debug.fail("Unexpected node kind.");
}
function visitBinaryExpression(node: BinaryExpression): Expression {
// We are here because ES7 adds support for the exponentiation operator.
const left = visitNode(node.left, visitor, isExpression);
const right = visitNode(node.right, visitor, isExpression);
if (node.operatorToken.kind === SyntaxKind.AsteriskAsteriskEqualsToken) {
let target: Expression;
let value: Expression;
if (isElementAccessExpression(left)) {
// Transforms `a[x] **= b` into `(_a = a)[_x = x] = Math.pow(_a[_x], b)`
const expressionTemp = createTempVariable();
hoistVariableDeclaration(expressionTemp);
const argumentExpressionTemp = createTempVariable();
hoistVariableDeclaration(argumentExpressionTemp);
target = createElementAccess(
createAssignment(expressionTemp, left.expression, /*location*/ left.expression),
createAssignment(argumentExpressionTemp, left.argumentExpression, /*location*/ left.argumentExpression),
/*location*/ left
);
value = createElementAccess(
expressionTemp,
argumentExpressionTemp,
/*location*/ left
);
}
else if (isPropertyAccessExpression(left)) {
// Transforms `a.x **= b` into `(_a = a).x = Math.pow(_a.x, b)`
const expressionTemp = createTempVariable();
hoistVariableDeclaration(expressionTemp);
target = createPropertyAccess(
createAssignment(expressionTemp, left.expression, /*location*/ left.expression),
left.name,
/*location*/ left
);
value = createPropertyAccess(
expressionTemp,
left.name,
/*location*/ left
);
}
else {
// Transforms `a **= b` into `a = Math.pow(a, b)`
target = left;
value = left;
}
return createAssignment(target, createMathPow(value, right, /*location*/ node), /*location*/ node);
}
else if (node.operatorToken.kind === SyntaxKind.AsteriskAsteriskToken) {
// Transforms `a ** b` into `Math.pow(a, b)`
return createMathPow(left, right, /*location*/ node);
}
else {
Debug.fail("Unexpected node kind.");
}
}
}
}