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[Flow] Function predicate declaration (#103)

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* [Flow] Function predicate declaration

The accepted syntax for function declarations is extended to allow
the following predicate declaration:

  FunctionReturnType :=
    Type
    Predicate
    Type Predicate

  Predicate :=
    %checks
    %checks ( ConditionalExpression )

* [Flow] Minor tweaks and more examples to function predicates

* [Flow] Clean-up and better message for function predicates

* [Flow] Adding abstract function predicate example

* [Flow] Rearranging the `predicate` field to ease babel generator.
This commit is contained in:
Panagiotis Vekris
2017-02-10 05:55:13 -08:00
committed by Daniel Tschinder
parent 898c4a7623
commit e049ec3456
13 changed files with 1415 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

54
src/plugins/flow.js
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@@ -28,6 +28,45 @@ pp.flowParseTypeInitialiser = function (tok) {
return type;
};
pp.flowParsePredicate = function() {
const node = this.startNode();
const moduloLoc = this.state.startLoc;
const moduloPos = this.state.start;
this.expect(tt.modulo);
const checksLoc = this.state.startLoc;
this.expectContextual("checks");
// Force '%' and 'checks' to be adjacent
if (moduloLoc.line !== checksLoc.line || moduloLoc.column !== checksLoc.column - 1) {
this.raise(moduloPos, "Spaces between ´%´ and ´checks´ are not allowed here.");
}
if (this.eat(tt.parenL)) {
node.expression = this.parseExpression();
this.expect(tt.parenR);
return this.finishNode(node, "DeclaredPredicate");
} else {
return this.finishNode(node, "InferredPredicate");
}
};
pp.flowParseTypeAndPredicateInitialiser = function () {
const oldInType = this.state.inType;
this.state.inType = true;
this.expect(tt.colon);
let type = null;
let predicate = null;
if (this.match(tt.modulo)) {
this.state.inType = oldInType;
predicate = this.flowParsePredicate();
} else {
type = this.flowParseType();
this.state.inType = oldInType;
if (this.match(tt.modulo)) {
predicate = this.flowParsePredicate();
}
}
return [type, predicate];
};
pp.flowParseDeclareClass = function (node) {
this.next();
this.flowParseInterfaceish(node, true);
@@ -53,9 +92,10 @@ pp.flowParseDeclareFunction = function (node) {
typeNode.params = tmp.params;
typeNode.rest = tmp.rest;
this.expect(tt.parenR);
typeNode.returnType = this.flowParseTypeInitialiser();
let predicate = null;
[typeNode.returnType, predicate] = this.flowParseTypeAndPredicateInitialiser();
typeContainer.typeAnnotation = this.finishNode(typeNode, "FunctionTypeAnnotation");
typeContainer.predicate = predicate;
id.typeAnnotation = this.finishNode(typeContainer, "TypeAnnotation");
this.finishNode(id, id.type);
@@ -789,6 +829,12 @@ pp.flowParseTypeAnnotation = function () {
return this.finishNode(node, "TypeAnnotation");
};
pp.flowParseTypeAndPredicateAnnotation = function () {
const node = this.startNode();
[node.typeAnnotation, node.predicate] = this.flowParseTypeAndPredicateInitialiser();
return this.finishNode(node, "TypeAnnotation");
};
pp.flowParseTypeAnnotatableIdentifier = function () {
const ident = this.flowParseRestrictedIdentifier();
if (this.match(tt.colon)) {
@@ -829,7 +875,7 @@ export default function (instance) {
if (this.match(tt.colon) && !allowExpression) {
// if allowExpression is true then we're parsing an arrow function and if
// there's a return type then it's been handled elsewhere
node.returnType = this.flowParseTypeAnnotation();
node.returnType = this.flowParseTypeAndPredicateAnnotation();
}
return inner.call(this, node, allowExpression);
@@ -1378,7 +1424,7 @@ export default function (instance) {
try {
const oldNoAnonFunctionType = this.state.noAnonFunctionType;
this.state.noAnonFunctionType = true;
const returnType = this.flowParseTypeAnnotation();
const returnType = this.flowParseTypeAndPredicateAnnotation();
this.state.noAnonFunctionType = oldNoAnonFunctionType;
if (this.canInsertSemicolon()) this.unexpected();