com.google.javascript.jscomp.parsing.parser.FeatureSet Maven / Gradle / Ivy
/*
* Copyright 2015 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp.parsing.parser;
import java.io.Serializable;
import java.util.Objects;
/**
* Represents various aspects of language version and support.
*
* This is somewhat redundant with LanguageMode, but is separate
* for two reasons: (1) it's used for parsing, which cannot
* depend on LanguageMode, and (2) it's concerned with slightly
* different nuances: implemented features and modules rather
* than strictness.
*
*
In the long term, it would be good to disentangle all these
* concerns and pull out a single LanguageSyntax enum with a
* separate strict mode flag, and then these could possibly be
* unified.
*
*
Instances of this class are immutable.
*/
public final class FeatureSet implements Serializable {
/** The number of the language version: 3, 5, or 6. */
private final int number;
/** Whether this includes features not supported in current stable browsers. */
private final boolean unsupported;
/** Whether ES6 modules are included. */
private final boolean es6Modules;
/** Whether TypeScript syntax is included (for .d.ts support). */
private final boolean typeScript;
/** The bare minimum set of features in ES3. */
public static final FeatureSet ES3 = new FeatureSet(3, false, false, false);
/** Features from ES5 only. */
public static final FeatureSet ES5 = new FeatureSet(5, false, false, false);
/** The subset of ES6 features that are implemented in stable Chrome, Firefox, and Edge. */
public static final FeatureSet ES6_IMPL = new FeatureSet(6, false, false, false);
/** The full set of ES6 features, not including modules. */
public static final FeatureSet ES6 = new FeatureSet(6, true, false, false);
/** All ES6 features, including modules. */
public static final FeatureSet ES6_MODULES = new FeatureSet(6, true, true, false);
public static final FeatureSet ES7 = new FeatureSet(7, true, false, false);
public static final FeatureSet ES7_MODULES = new FeatureSet(7, true, true, false);
public static final FeatureSet ES8 = new FeatureSet(8, true, false, false);
public static final FeatureSet ES8_MODULES = new FeatureSet(8, true, true, false);
/** TypeScript syntax. */
public static final FeatureSet TYPESCRIPT = new FeatureSet(8, true, true, true);
/**
* Specific features that can be included (indirectly) in a FeatureSet.
* This primarily adds a name so that helper functions can simultaneously
* update the detected features and also warn about unsupported features
* by name. Additionally, collecting these all in one place provides a
* single file that needs to be edited to update the current browser support.
*/
public enum Feature {
// ES5 features
ES3_KEYWORDS_AS_IDENTIFIERS("ES3 keywords as identifiers", ES5),
GETTER("getters", ES5),
KEYWORDS_AS_PROPERTIES("reserved words as properties", ES5),
SETTER("setters", ES5),
STRING_CONTINUATION("string continuation", ES5),
TRAILING_COMMA("trailing comma", ES5),
// ES6 features that are already implemented in modern stable browsers
// (Chrome 50, Firefox 46, and Edge 13)
ARROW_FUNCTIONS("arrow function", ES6_IMPL),
BINARY_LITERALS("binary literal", ES6_IMPL),
OCTAL_LITERALS("octal literal", ES6_IMPL),
CLASSES("class", ES6_IMPL),
COMPUTED_PROPERTIES("computed property", ES6_IMPL),
EXTENDED_OBJECT_LITERALS("extended object literal", ES6_IMPL),
FOR_OF("for-of loop", ES6_IMPL),
GENERATORS("generator", ES6_IMPL),
LET_DECLARATIONS("let declaration", ES6_IMPL),
MEMBER_DECLARATIONS("member declaration", ES6_IMPL),
REGEXP_FLAG_Y("RegExp flag 'y'", ES6_IMPL),
REST_PARAMETERS("rest parameter", ES6_IMPL),
SPREAD_EXPRESSIONS("spread expression", ES6_IMPL),
SUPER("super", ES6_IMPL),
TEMPLATE_LITERALS("template literal", ES6_IMPL),
// ES6 features that are not yet implemented in all "modern" browsers
// The following features will become stable once Edge 14 is released:
CONST_DECLARATIONS("const declaration", ES6),
DESTRUCTURING("destructuring", ES6),
NEW_TARGET("new.target", ES6), // Not fully supported until Edge 14
REGEXP_FLAG_U("RegExp flag 'u'", ES6), // (note: case folding still broken even in Edge 14)
// The following features are still broken even in Firefox 49:
// See https://bugzilla.mozilla.org/show_bug.cgi?id=1187502 for details
DEFAULT_PARAMETERS("default parameter", ES6),
// ES6 features that include modules
MODULES("modules", ES6_MODULES),
// '**' operator
EXPONENT_OP("exponent operator (**)", ES7),
// http://tc39.github.io/ecmascript-asyncawait/
ASYNC_FUNCTIONS("async function", ES8),
// ES6 typed features that are not at all implemented in browsers
AMBIENT_DECLARATION("ambient declaration", TYPESCRIPT),
CALL_SIGNATURE("call signature", TYPESCRIPT),
CONSTRUCTOR_SIGNATURE("constructor signature", TYPESCRIPT),
ENUM("enum", TYPESCRIPT),
GENERICS("generics", TYPESCRIPT),
IMPLEMENTS("implements", TYPESCRIPT),
INDEX_SIGNATURE("index signature", TYPESCRIPT),
INTERFACE("interface", TYPESCRIPT),
MEMBER_VARIABLE_IN_CLASS("member variable in class", TYPESCRIPT),
NAMESPACE_DECLARATION("namespace declaration", TYPESCRIPT),
OPTIONAL_PARAMETER("optional parameter", TYPESCRIPT),
TYPE_ALIAS("type alias", TYPESCRIPT),
TYPE_ANNOTATION("type annotation", TYPESCRIPT);
private final String name;
private final FeatureSet features;
private Feature(String name, FeatureSet features) {
this.name = name;
this.features = features;
}
public FeatureSet features() {
return features;
}
@Override
public String toString() {
return name;
}
}
private FeatureSet(int number, boolean unsupported, boolean es6Modules, boolean typeScript) {
this.number = number;
this.unsupported = unsupported;
this.es6Modules = es6Modules;
this.typeScript = typeScript;
}
/** Returns a string representation suitable for encoding in depgraph and deps.js files. */
public String version() {
if (typeScript) {
return "ts";
} else if (number > 6) {
return "es" + number;
} else if (unsupported || es6Modules) {
return "es6";
} else if (number > 5) {
return "es6-impl";
} else if (number > 3) {
return "es5";
}
return "es3";
}
/** Returns whether this feature set includes ES6 modules. */
public boolean hasEs6Modules() {
return es6Modules;
}
/** Returns whether this feature set includes typescript features. */
public boolean isTypeScript() {
return typeScript;
}
/** Returns a feature set combining all the features from {@code this} and {@code other}. */
public FeatureSet require(FeatureSet other) {
return this.contains(other) ? this : this.union(other);
}
/**
* Returns a new {@link FeatureSet} including all features of both {@code this} and {@code other}.
*/
public FeatureSet union(FeatureSet other) {
return new FeatureSet(
Math.max(number, other.number),
unsupported || other.unsupported,
es6Modules || other.es6Modules,
typeScript || other.typeScript);
}
/**
* Does this {@link FeatureSet} contain all of the features of {@code other}?
*/
public boolean contains(FeatureSet other) {
return this.number >= other.number
&& (this.unsupported || !other.unsupported)
&& (this.es6Modules || !other.es6Modules)
&& (this.typeScript || !other.typeScript);
}
/** Returns a feature set combining all the features from {@code this} and {@code feature}. */
public FeatureSet require(Feature feature) {
return require(feature.features);
}
/**
* Does this {@link FeatureSet} include {@code feature}?
*/
public boolean contains(Feature feature) {
return contains(feature.features());
}
@Override
public boolean equals(Object other) {
return other instanceof FeatureSet
&& ((FeatureSet) other).number == number
&& ((FeatureSet) other).unsupported == unsupported
&& ((FeatureSet) other).es6Modules == es6Modules
&& ((FeatureSet) other).typeScript == typeScript;
}
@Override
public int hashCode() {
return Objects.hash(number, unsupported, es6Modules, typeScript);
}
@Override
public String toString() {
return "FeatureSet{number=" + number
+ (unsupported ? ", unsupported" : "")
+ (es6Modules ? ", es6Modules" : "")
+ (typeScript ? ", typeScript" : "")
+ "}";
}
/** Returns a the name of a corresponding LanguageMode enum element. */
public String toLanguageModeString() {
return "ECMASCRIPT" + number;
}
/** Parses known strings into feature sets. */
public static FeatureSet valueOf(String name) {
switch (name) {
case "es3":
return ES3;
case "es5":
return ES5;
case "es6-impl":
return ES6_IMPL;
case "es6":
return ES6;
case "ts":
return TYPESCRIPT;
default:
throw new IllegalArgumentException("No such FeatureSet: " + name);
}
}
public boolean isEs6ImplOrHigher() {
String version = version();
return !version.equals("es3") && !version.equals("es5");
}
}