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gecko-dev/intl/l10n/FluentSyntax.jsm

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44 KiB
JavaScript
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/* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
/* Copyright 2019 Mozilla Foundation and others
*
* 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.
*/
/* fluent-syntax@0.12.0 */
/*
* Base class for all Fluent AST nodes.
*
* All productions described in the ASDL subclass BaseNode, including Span and
* Annotation.
*
*/
class BaseNode {
constructor() {}
equals(other, ignoredFields = ["span"]) {
const thisKeys = new Set(Object.keys(this));
const otherKeys = new Set(Object.keys(other));
if (ignoredFields) {
for (const fieldName of ignoredFields) {
thisKeys.delete(fieldName);
otherKeys.delete(fieldName);
}
}
if (thisKeys.size !== otherKeys.size) {
return false;
}
for (const fieldName of thisKeys) {
if (!otherKeys.has(fieldName)) {
return false;
}
const thisVal = this[fieldName];
const otherVal = other[fieldName];
if (typeof thisVal !== typeof otherVal) {
return false;
}
if (thisVal instanceof Array) {
if (thisVal.length !== otherVal.length) {
return false;
}
for (let i = 0; i < thisVal.length; ++i) {
if (!scalarsEqual(thisVal[i], otherVal[i], ignoredFields)) {
return false;
}
}
} else if (!scalarsEqual(thisVal, otherVal, ignoredFields)) {
return false;
}
}
return true;
}
clone() {
function visit(value) {
if (value instanceof BaseNode) {
return value.clone();
}
if (Array.isArray(value)) {
return value.map(visit);
}
return value;
}
const clone = Object.create(this.constructor.prototype);
for (const prop of Object.keys(this)) {
clone[prop] = visit(this[prop]);
}
return clone;
}
}
function scalarsEqual(thisVal, otherVal, ignoredFields) {
if (thisVal instanceof BaseNode) {
return thisVal.equals(otherVal, ignoredFields);
}
return thisVal === otherVal;
}
/*
* Base class for AST nodes which can have Spans.
*/
class SyntaxNode extends BaseNode {
addSpan(start, end) {
this.span = new Span(start, end);
}
}
class Resource extends SyntaxNode {
constructor(body = []) {
super();
this.type = "Resource";
this.body = body;
}
}
/*
* An abstract base class for useful elements of Resource.body.
*/
class Entry extends SyntaxNode {}
class Message extends Entry {
constructor(id, value = null, attributes = [], comment = null) {
super();
this.type = "Message";
this.id = id;
this.value = value;
this.attributes = attributes;
this.comment = comment;
}
}
class Term extends Entry {
constructor(id, value, attributes = [], comment = null) {
super();
this.type = "Term";
this.id = id;
this.value = value;
this.attributes = attributes;
this.comment = comment;
}
}
class Pattern extends SyntaxNode {
constructor(elements) {
super();
this.type = "Pattern";
this.elements = elements;
}
}
/*
* An abstract base class for elements of Patterns.
*/
class PatternElement extends SyntaxNode {}
class TextElement extends PatternElement {
constructor(value) {
super();
this.type = "TextElement";
this.value = value;
}
}
class Placeable extends PatternElement {
constructor(expression) {
super();
this.type = "Placeable";
this.expression = expression;
}
}
/*
* An abstract base class for expressions.
*/
class Expression extends SyntaxNode {}
// An abstract base class for Literals.
class Literal extends Expression {
constructor(value) {
super();
// The "value" field contains the exact contents of the literal,
// character-for-character.
this.value = value;
}
parse() {
return {value: this.value};
}
}
class StringLiteral extends Literal {
constructor(value) {
super(value);
this.type = "StringLiteral";
}
parse() {
// Backslash backslash, backslash double quote, uHHHH, UHHHHHH.
const KNOWN_ESCAPES =
/(?:\\\\|\\"|\\u([0-9a-fA-F]{4})|\\U([0-9a-fA-F]{6}))/g;
function from_escape_sequence(match, codepoint4, codepoint6) {
switch (match) {
case "\\\\":
return "\\";
case "\\\"":
return "\"";
default:
let codepoint = parseInt(codepoint4 || codepoint6, 16);
if (codepoint <= 0xD7FF || 0xE000 <= codepoint) {
// It's a Unicode scalar value.
return String.fromCodePoint(codepoint);
}
// Escape sequences reresenting surrogate code points are
// well-formed but invalid in Fluent. Replace them with U+FFFD
// REPLACEMENT CHARACTER.
return "<22>";
}
}
let value = this.value.replace(KNOWN_ESCAPES, from_escape_sequence);
return {value};
}
}
class NumberLiteral extends Literal {
constructor(value) {
super(value);
this.type = "NumberLiteral";
}
parse() {
let value = parseFloat(this.value);
let decimal_position = this.value.indexOf(".");
let precision = decimal_position > 0
? this.value.length - decimal_position - 1
: 0;
return {value, precision};
}
}
class MessageReference extends Expression {
constructor(id, attribute = null) {
super();
this.type = "MessageReference";
this.id = id;
this.attribute = attribute;
}
}
class TermReference extends Expression {
constructor(id, attribute = null, args = null) {
super();
this.type = "TermReference";
this.id = id;
this.attribute = attribute;
this.arguments = args;
}
}
class VariableReference extends Expression {
constructor(id) {
super();
this.type = "VariableReference";
this.id = id;
}
}
class FunctionReference extends Expression {
constructor(id, args) {
super();
this.type = "FunctionReference";
this.id = id;
this.arguments = args;
}
}
class SelectExpression extends Expression {
constructor(selector, variants) {
super();
this.type = "SelectExpression";
this.selector = selector;
this.variants = variants;
}
}
class CallArguments extends SyntaxNode {
constructor(positional = [], named = []) {
super();
this.type = "CallArguments";
this.positional = positional;
this.named = named;
}
}
class Attribute extends SyntaxNode {
constructor(id, value) {
super();
this.type = "Attribute";
this.id = id;
this.value = value;
}
}
class Variant extends SyntaxNode {
constructor(key, value, def = false) {
super();
this.type = "Variant";
this.key = key;
this.value = value;
this.default = def;
}
}
class NamedArgument extends SyntaxNode {
constructor(name, value) {
super();
this.type = "NamedArgument";
this.name = name;
this.value = value;
}
}
class Identifier extends SyntaxNode {
constructor(name) {
super();
this.type = "Identifier";
this.name = name;
}
}
class BaseComment extends Entry {
constructor(content) {
super();
this.type = "BaseComment";
this.content = content;
}
}
class Comment extends BaseComment {
constructor(content) {
super(content);
this.type = "Comment";
}
}
class GroupComment extends BaseComment {
constructor(content) {
super(content);
this.type = "GroupComment";
}
}
class ResourceComment extends BaseComment {
constructor(content) {
super(content);
this.type = "ResourceComment";
}
}
class Junk extends SyntaxNode {
constructor(content) {
super();
this.type = "Junk";
this.annotations = [];
this.content = content;
}
addAnnotation(annot) {
this.annotations.push(annot);
}
}
class Span extends BaseNode {
constructor(start, end) {
super();
this.type = "Span";
this.start = start;
this.end = end;
}
}
class Annotation extends SyntaxNode {
constructor(code, args = [], message) {
super();
this.type = "Annotation";
this.code = code;
this.arguments = args;
this.message = message;
}
}
const ast = ({
BaseNode: BaseNode,
Resource: Resource,
Entry: Entry,
Message: Message,
Term: Term,
Pattern: Pattern,
PatternElement: PatternElement,
TextElement: TextElement,
Placeable: Placeable,
Expression: Expression,
Literal: Literal,
StringLiteral: StringLiteral,
NumberLiteral: NumberLiteral,
MessageReference: MessageReference,
TermReference: TermReference,
VariableReference: VariableReference,
FunctionReference: FunctionReference,
SelectExpression: SelectExpression,
CallArguments: CallArguments,
Attribute: Attribute,
Variant: Variant,
NamedArgument: NamedArgument,
Identifier: Identifier,
BaseComment: BaseComment,
Comment: Comment,
GroupComment: GroupComment,
ResourceComment: ResourceComment,
Junk: Junk,
Span: Span,
Annotation: Annotation
});
class ParseError extends Error {
constructor(code, ...args) {
super();
this.code = code;
this.args = args;
this.message = getErrorMessage(code, args);
}
}
/* eslint-disable complexity */
function getErrorMessage(code, args) {
switch (code) {
case "E0001":
return "Generic error";
case "E0002":
return "Expected an entry start";
case "E0003": {
const [token] = args;
return `Expected token: "${token}"`;
}
case "E0004": {
const [range] = args;
return `Expected a character from range: "${range}"`;
}
case "E0005": {
const [id] = args;
return `Expected message "${id}" to have a value or attributes`;
}
case "E0006": {
const [id] = args;
return `Expected term "-${id}" to have a value`;
}
case "E0007":
return "Keyword cannot end with a whitespace";
case "E0008":
return "The callee has to be an upper-case identifier or a term";
case "E0009":
return "The argument name has to be a simple identifier";
case "E0010":
return "Expected one of the variants to be marked as default (*)";
case "E0011":
return 'Expected at least one variant after "->"';
case "E0012":
return "Expected value";
case "E0013":
return "Expected variant key";
case "E0014":
return "Expected literal";
case "E0015":
return "Only one variant can be marked as default (*)";
case "E0016":
return "Message references cannot be used as selectors";
case "E0017":
return "Terms cannot be used as selectors";
case "E0018":
return "Attributes of messages cannot be used as selectors";
case "E0019":
return "Attributes of terms cannot be used as placeables";
case "E0020":
return "Unterminated string expression";
case "E0021":
return "Positional arguments must not follow named arguments";
case "E0022":
return "Named arguments must be unique";
case "E0024":
return "Cannot access variants of a message.";
case "E0025": {
const [char] = args;
return `Unknown escape sequence: \\${char}.`;
}
case "E0026": {
const [sequence] = args;
return `Invalid Unicode escape sequence: ${sequence}.`;
}
case "E0027":
return "Unbalanced closing brace in TextElement.";
case "E0028":
return "Expected an inline expression";
default:
return code;
}
}
function includes(arr, elem) {
return arr.indexOf(elem) > -1;
}
/* eslint no-magic-numbers: "off" */
class ParserStream {
constructor(string) {
this.string = string;
this.index = 0;
this.peekOffset = 0;
}
charAt(offset) {
// When the cursor is at CRLF, return LF but don't move the cursor.
// The cursor still points to the EOL position, which in this case is the
// beginning of the compound CRLF sequence. This ensures slices of
// [inclusive, exclusive) continue to work properly.
if (this.string[offset] === "\r"
&& this.string[offset + 1] === "\n") {
return "\n";
}
return this.string[offset];
}
get currentChar() {
return this.charAt(this.index);
}
get currentPeek() {
return this.charAt(this.index + this.peekOffset);
}
next() {
this.peekOffset = 0;
// Skip over the CRLF as if it was a single character.
if (this.string[this.index] === "\r"
&& this.string[this.index + 1] === "\n") {
this.index++;
}
this.index++;
return this.string[this.index];
}
peek() {
// Skip over the CRLF as if it was a single character.
if (this.string[this.index + this.peekOffset] === "\r"
&& this.string[this.index + this.peekOffset + 1] === "\n") {
this.peekOffset++;
}
this.peekOffset++;
return this.string[this.index + this.peekOffset];
}
resetPeek(offset = 0) {
this.peekOffset = offset;
}
skipToPeek() {
this.index += this.peekOffset;
this.peekOffset = 0;
}
}
const EOL = "\n";
const EOF = undefined;
const SPECIAL_LINE_START_CHARS = ["}", ".", "[", "*"];
class FluentParserStream extends ParserStream {
peekBlankInline() {
const start = this.index + this.peekOffset;
while (this.currentPeek === " ") {
this.peek();
}
return this.string.slice(start, this.index + this.peekOffset);
}
skipBlankInline() {
const blank = this.peekBlankInline();
this.skipToPeek();
return blank;
}
peekBlankBlock() {
let blank = "";
while (true) {
const lineStart = this.peekOffset;
this.peekBlankInline();
if (this.currentPeek === EOL) {
blank += EOL;
this.peek();
continue;
}
if (this.currentPeek === EOF) {
// Treat the blank line at EOF as a blank block.
return blank;
}
// Any other char; reset to column 1 on this line.
this.resetPeek(lineStart);
return blank;
}
}
skipBlankBlock() {
const blank = this.peekBlankBlock();
this.skipToPeek();
return blank;
}
peekBlank() {
while (this.currentPeek === " " || this.currentPeek === EOL) {
this.peek();
}
}
skipBlank() {
this.peekBlank();
this.skipToPeek();
}
expectChar(ch) {
if (this.currentChar === ch) {
this.next();
return true;
}
throw new ParseError("E0003", ch);
}
expectLineEnd() {
if (this.currentChar === EOF) {
// EOF is a valid line end in Fluent.
return true;
}
if (this.currentChar === EOL) {
this.next();
return true;
}
// Unicode Character 'SYMBOL FOR NEWLINE' (U+2424)
throw new ParseError("E0003", "\u2424");
}
takeChar(f) {
const ch = this.currentChar;
if (ch === EOF) {
return EOF;
}
if (f(ch)) {
this.next();
return ch;
}
return null;
}
isCharIdStart(ch) {
if (ch === EOF) {
return false;
}
const cc = ch.charCodeAt(0);
return (cc >= 97 && cc <= 122) || // a-z
(cc >= 65 && cc <= 90); // A-Z
}
isIdentifierStart() {
return this.isCharIdStart(this.currentPeek);
}
isNumberStart() {
const ch = this.currentChar === "-"
? this.peek()
: this.currentChar;
if (ch === EOF) {
this.resetPeek();
return false;
}
const cc = ch.charCodeAt(0);
const isDigit = cc >= 48 && cc <= 57; // 0-9
this.resetPeek();
return isDigit;
}
isCharPatternContinuation(ch) {
if (ch === EOF) {
return false;
}
return !includes(SPECIAL_LINE_START_CHARS, ch);
}
isValueStart() {
// Inline Patterns may start with any char.
const ch = this.currentPeek;
return ch !== EOL && ch !== EOF;
}
isValueContinuation() {
const column1 = this.peekOffset;
this.peekBlankInline();
if (this.currentPeek === "{") {
this.resetPeek(column1);
return true;
}
if (this.peekOffset - column1 === 0) {
return false;
}
if (this.isCharPatternContinuation(this.currentPeek)) {
this.resetPeek(column1);
return true;
}
return false;
}
// -1 - any
// 0 - comment
// 1 - group comment
// 2 - resource comment
isNextLineComment(level = -1) {
if (this.currentChar !== EOL) {
return false;
}
let i = 0;
while (i <= level || (level === -1 && i < 3)) {
if (this.peek() !== "#") {
if (i <= level && level !== -1) {
this.resetPeek();
return false;
}
break;
}
i++;
}
// The first char after #, ## or ###.
const ch = this.peek();
if (ch === " " || ch === EOL) {
this.resetPeek();
return true;
}
this.resetPeek();
return false;
}
isVariantStart() {
const currentPeekOffset = this.peekOffset;
if (this.currentPeek === "*") {
this.peek();
}
if (this.currentPeek === "[") {
this.resetPeek(currentPeekOffset);
return true;
}
this.resetPeek(currentPeekOffset);
return false;
}
isAttributeStart() {
return this.currentPeek === ".";
}
skipToNextEntryStart(junkStart) {
let lastNewline = this.string.lastIndexOf(EOL, this.index);
if (junkStart < lastNewline) {
// Last seen newline is _after_ the junk start. It's safe to rewind
// without the risk of resuming at the same broken entry.
this.index = lastNewline;
}
while (this.currentChar) {
// We're only interested in beginnings of line.
if (this.currentChar !== EOL) {
this.next();
continue;
}
// Break if the first char in this line looks like an entry start.
const first = this.next();
if (this.isCharIdStart(first) || first === "-" || first === "#") {
break;
}
}
}
takeIDStart() {
if (this.isCharIdStart(this.currentChar)) {
const ret = this.currentChar;
this.next();
return ret;
}
throw new ParseError("E0004", "a-zA-Z");
}
takeIDChar() {
const closure = ch => {
const cc = ch.charCodeAt(0);
return ((cc >= 97 && cc <= 122) || // a-z
(cc >= 65 && cc <= 90) || // A-Z
(cc >= 48 && cc <= 57) || // 0-9
cc === 95 || cc === 45); // _-
};
return this.takeChar(closure);
}
takeDigit() {
const closure = ch => {
const cc = ch.charCodeAt(0);
return (cc >= 48 && cc <= 57); // 0-9
};
return this.takeChar(closure);
}
takeHexDigit() {
const closure = ch => {
const cc = ch.charCodeAt(0);
return (cc >= 48 && cc <= 57) // 0-9
|| (cc >= 65 && cc <= 70) // A-F
|| (cc >= 97 && cc <= 102); // a-f
};
return this.takeChar(closure);
}
}
/* eslint no-magic-numbers: [0] */
const trailingWSRe = /[ \t\n\r]+$/;
function withSpan(fn) {
return function(ps, ...args) {
if (!this.withSpans) {
return fn.call(this, ps, ...args);
}
const start = ps.index;
const node = fn.call(this, ps, ...args);
// Don't re-add the span if the node already has it. This may happen when
// one decorated function calls another decorated function.
if (node.span) {
return node;
}
const end = ps.index;
node.addSpan(start, end);
return node;
};
}
class FluentParser {
constructor({
withSpans = true,
} = {}) {
this.withSpans = withSpans;
// Poor man's decorators.
const methodNames = [
"getComment", "getMessage", "getTerm", "getAttribute", "getIdentifier",
"getVariant", "getNumber", "getPattern", "getTextElement",
"getPlaceable", "getExpression", "getInlineExpression",
"getCallArgument", "getCallArguments", "getString", "getLiteral",
];
for (const name of methodNames) {
this[name] = withSpan(this[name]);
}
}
parse(source) {
const ps = new FluentParserStream(source);
ps.skipBlankBlock();
const entries = [];
let lastComment = null;
while (ps.currentChar) {
const entry = this.getEntryOrJunk(ps);
const blankLines = ps.skipBlankBlock();
// Regular Comments require special logic. Comments may be attached to
// Messages or Terms if they are followed immediately by them. However
// they should parse as standalone when they're followed by Junk.
// Consequently, we only attach Comments once we know that the Message
// or the Term parsed successfully.
if (entry.type === "Comment"
&& blankLines.length === 0
&& ps.currentChar) {
// Stash the comment and decide what to do with it in the next pass.
lastComment = entry;
continue;
}
if (lastComment) {
if (entry.type === "Message" || entry.type === "Term") {
entry.comment = lastComment;
if (this.withSpans) {
entry.span.start = entry.comment.span.start;
}
} else {
entries.push(lastComment);
}
// In either case, the stashed comment has been dealt with; clear it.
lastComment = null;
}
// No special logic for other types of entries.
entries.push(entry);
}
const res = new Resource(entries);
if (this.withSpans) {
res.addSpan(0, ps.index);
}
return res;
}
/*
* Parse the first Message or Term in `source`.
*
* Skip all encountered comments and start parsing at the first Message or
* Term start. Return Junk if the parsing is not successful.
*
* Preceding comments are ignored unless they contain syntax errors
* themselves, in which case Junk for the invalid comment is returned.
*/
parseEntry(source) {
const ps = new FluentParserStream(source);
ps.skipBlankBlock();
while (ps.currentChar === "#") {
const skipped = this.getEntryOrJunk(ps);
if (skipped.type === "Junk") {
// Don't skip Junk comments.
return skipped;
}
ps.skipBlankBlock();
}
return this.getEntryOrJunk(ps);
}
getEntryOrJunk(ps) {
const entryStartPos = ps.index;
try {
const entry = this.getEntry(ps);
ps.expectLineEnd();
return entry;
} catch (err) {
if (!(err instanceof ParseError)) {
throw err;
}
let errorIndex = ps.index;
ps.skipToNextEntryStart(entryStartPos);
const nextEntryStart = ps.index;
if (nextEntryStart < errorIndex) {
// The position of the error must be inside of the Junk's span.
errorIndex = nextEntryStart;
}
// Create a Junk instance
const slice = ps.string.substring(entryStartPos, nextEntryStart);
const junk = new Junk(slice);
if (this.withSpans) {
junk.addSpan(entryStartPos, nextEntryStart);
}
const annot = new Annotation(err.code, err.args, err.message);
annot.addSpan(errorIndex, errorIndex);
junk.addAnnotation(annot);
return junk;
}
}
getEntry(ps) {
if (ps.currentChar === "#") {
return this.getComment(ps);
}
if (ps.currentChar === "-") {
return this.getTerm(ps);
}
if (ps.isIdentifierStart()) {
return this.getMessage(ps);
}
throw new ParseError("E0002");
}
getComment(ps) {
// 0 - comment
// 1 - group comment
// 2 - resource comment
let level = -1;
let content = "";
while (true) {
let i = -1;
while (ps.currentChar === "#" && (i < (level === -1 ? 2 : level))) {
ps.next();
i++;
}
if (level === -1) {
level = i;
}
if (ps.currentChar !== EOL) {
ps.expectChar(" ");
let ch;
while ((ch = ps.takeChar(x => x !== EOL))) {
content += ch;
}
}
if (ps.isNextLineComment(level)) {
content += ps.currentChar;
ps.next();
} else {
break;
}
}
let Comment$$1;
switch (level) {
case 0:
Comment$$1 = Comment;
break;
case 1:
Comment$$1 = GroupComment;
break;
case 2:
Comment$$1 = ResourceComment;
break;
}
return new Comment$$1(content);
}
getMessage(ps) {
const id = this.getIdentifier(ps);
ps.skipBlankInline();
ps.expectChar("=");
const value = this.maybeGetPattern(ps);
const attrs = this.getAttributes(ps);
if (value === null && attrs.length === 0) {
throw new ParseError("E0005", id.name);
}
return new Message(id, value, attrs);
}
getTerm(ps) {
ps.expectChar("-");
const id = this.getIdentifier(ps);
ps.skipBlankInline();
ps.expectChar("=");
const value = this.maybeGetPattern(ps);
if (value === null) {
throw new ParseError("E0006", id.name);
}
const attrs = this.getAttributes(ps);
return new Term(id, value, attrs);
}
getAttribute(ps) {
ps.expectChar(".");
const key = this.getIdentifier(ps);
ps.skipBlankInline();
ps.expectChar("=");
const value = this.maybeGetPattern(ps);
if (value === null) {
throw new ParseError("E0012");
}
return new Attribute(key, value);
}
getAttributes(ps) {
const attrs = [];
ps.peekBlank();
while (ps.isAttributeStart()) {
ps.skipToPeek();
const attr = this.getAttribute(ps);
attrs.push(attr);
ps.peekBlank();
}
return attrs;
}
getIdentifier(ps) {
let name = ps.takeIDStart();
let ch;
while ((ch = ps.takeIDChar())) {
name += ch;
}
return new Identifier(name);
}
getVariantKey(ps) {
const ch = ps.currentChar;
if (ch === EOF) {
throw new ParseError("E0013");
}
const cc = ch.charCodeAt(0);
if ((cc >= 48 && cc <= 57) || cc === 45) { // 0-9, -
return this.getNumber(ps);
}
return this.getIdentifier(ps);
}
getVariant(ps, {hasDefault}) {
let defaultIndex = false;
if (ps.currentChar === "*") {
if (hasDefault) {
throw new ParseError("E0015");
}
ps.next();
defaultIndex = true;
}
ps.expectChar("[");
ps.skipBlank();
const key = this.getVariantKey(ps);
ps.skipBlank();
ps.expectChar("]");
const value = this.maybeGetPattern(ps);
if (value === null) {
throw new ParseError("E0012");
}
return new Variant(key, value, defaultIndex);
}
getVariants(ps) {
const variants = [];
let hasDefault = false;
ps.skipBlank();
while (ps.isVariantStart()) {
const variant = this.getVariant(ps, {hasDefault});
if (variant.default) {
hasDefault = true;
}
variants.push(variant);
ps.expectLineEnd();
ps.skipBlank();
}
if (variants.length === 0) {
throw new ParseError("E0011");
}
if (!hasDefault) {
throw new ParseError("E0010");
}
return variants;
}
getDigits(ps) {
let num = "";
let ch;
while ((ch = ps.takeDigit())) {
num += ch;
}
if (num.length === 0) {
throw new ParseError("E0004", "0-9");
}
return num;
}
getNumber(ps) {
let value = "";
if (ps.currentChar === "-") {
ps.next();
value += `-${this.getDigits(ps)}`;
} else {
value += this.getDigits(ps);
}
if (ps.currentChar === ".") {
ps.next();
value += `.${this.getDigits(ps)}`;
}
return new NumberLiteral(value);
}
// maybeGetPattern distinguishes between patterns which start on the same line
// as the identifier (a.k.a. inline signleline patterns and inline multiline
// patterns) and patterns which start on a new line (a.k.a. block multiline
// patterns). The distinction is important for the dedentation logic: the
// indent of the first line of a block pattern must be taken into account when
// calculating the maximum common indent.
maybeGetPattern(ps) {
ps.peekBlankInline();
if (ps.isValueStart()) {
ps.skipToPeek();
return this.getPattern(ps, {isBlock: false});
}
ps.peekBlankBlock();
if (ps.isValueContinuation()) {
ps.skipToPeek();
return this.getPattern(ps, {isBlock: true});
}
return null;
}
getPattern(ps, {isBlock}) {
const elements = [];
if (isBlock) {
// A block pattern is a pattern which starts on a new line. Store and
// measure the indent of this first line for the dedentation logic.
const blankStart = ps.index;
const firstIndent = ps.skipBlankInline();
elements.push(this.getIndent(ps, firstIndent, blankStart));
var commonIndentLength = firstIndent.length;
} else {
commonIndentLength = Infinity;
}
let ch;
elements: while ((ch = ps.currentChar)) {
switch (ch) {
case EOL: {
const blankStart = ps.index;
const blankLines = ps.peekBlankBlock();
if (ps.isValueContinuation()) {
ps.skipToPeek();
const indent = ps.skipBlankInline();
commonIndentLength = Math.min(commonIndentLength, indent.length);
elements.push(this.getIndent(ps, blankLines + indent, blankStart));
continue elements;
}
// The end condition for getPattern's while loop is a newline
// which is not followed by a valid pattern continuation.
ps.resetPeek();
break elements;
}
case "{":
elements.push(this.getPlaceable(ps));
continue elements;
case "}":
throw new ParseError("E0027");
default:
const element = this.getTextElement(ps);
elements.push(element);
}
}
const dedented = this.dedent(elements, commonIndentLength);
return new Pattern(dedented);
}
// Create a token representing an indent. It's not part of the AST and it will
// be trimmed and merged into adjacent TextElements, or turned into a new
// TextElement, if it's surrounded by two Placeables.
getIndent(ps, value, start) {
return {
type: "Indent",
span: {start, end: ps.index},
value,
};
}
// Dedent a list of elements by removing the maximum common indent from the
// beginning of text lines. The common indent is calculated in getPattern.
dedent(elements, commonIndent) {
const trimmed = [];
for (let element of elements) {
if (element.type === "Placeable") {
trimmed.push(element);
continue;
}
if (element.type === "Indent") {
// Strip common indent.
element.value = element.value.slice(
0, element.value.length - commonIndent);
if (element.value.length === 0) {
continue;
}
}
let prev = trimmed[trimmed.length - 1];
if (prev && prev.type === "TextElement") {
// Join adjacent TextElements by replacing them with their sum.
const sum = new TextElement(prev.value + element.value);
if (this.withSpans) {
sum.addSpan(prev.span.start, element.span.end);
}
trimmed[trimmed.length - 1] = sum;
continue;
}
if (element.type === "Indent") {
// If the indent hasn't been merged into a preceding TextElement,
// convert it into a new TextElement.
const textElement = new TextElement(element.value);
if (this.withSpans) {
textElement.addSpan(element.span.start, element.span.end);
}
element = textElement;
}
trimmed.push(element);
}
// Trim trailing whitespace from the Pattern.
const lastElement = trimmed[trimmed.length - 1];
if (lastElement.type === "TextElement") {
lastElement.value = lastElement.value.replace(trailingWSRe, "");
if (lastElement.value.length === 0) {
trimmed.pop();
}
}
return trimmed;
}
getTextElement(ps) {
let buffer = "";
let ch;
while ((ch = ps.currentChar)) {
if (ch === "{" || ch === "}") {
return new TextElement(buffer);
}
if (ch === EOL) {
return new TextElement(buffer);
}
buffer += ch;
ps.next();
}
return new TextElement(buffer);
}
getEscapeSequence(ps) {
const next = ps.currentChar;
switch (next) {
case "\\":
case "\"":
ps.next();
return `\\${next}`;
case "u":
return this.getUnicodeEscapeSequence(ps, next, 4);
case "U":
return this.getUnicodeEscapeSequence(ps, next, 6);
default:
throw new ParseError("E0025", next);
}
}
getUnicodeEscapeSequence(ps, u, digits) {
ps.expectChar(u);
let sequence = "";
for (let i = 0; i < digits; i++) {
const ch = ps.takeHexDigit();
if (!ch) {
throw new ParseError(
"E0026", `\\${u}${sequence}${ps.currentChar}`);
}
sequence += ch;
}
return `\\${u}${sequence}`;
}
getPlaceable(ps) {
ps.expectChar("{");
ps.skipBlank();
const expression = this.getExpression(ps);
ps.expectChar("}");
return new Placeable(expression);
}
getExpression(ps) {
const selector = this.getInlineExpression(ps);
ps.skipBlank();
if (ps.currentChar === "-") {
if (ps.peek() !== ">") {
ps.resetPeek();
return selector;
}
if (selector.type === "MessageReference") {
if (selector.attribute === null) {
throw new ParseError("E0016");
} else {
throw new ParseError("E0018");
}
}
if (selector.type === "TermReference" && selector.attribute === null) {
throw new ParseError("E0017");
}
ps.next();
ps.next();
ps.skipBlankInline();
ps.expectLineEnd();
const variants = this.getVariants(ps);
return new SelectExpression(selector, variants);
}
if (selector.type === "TermReference" && selector.attribute !== null) {
throw new ParseError("E0019");
}
return selector;
}
getInlineExpression(ps) {
if (ps.currentChar === "{") {
return this.getPlaceable(ps);
}
if (ps.isNumberStart()) {
return this.getNumber(ps);
}
if (ps.currentChar === '"') {
return this.getString(ps);
}
if (ps.currentChar === "$") {
ps.next();
const id = this.getIdentifier(ps);
return new VariableReference(id);
}
if (ps.currentChar === "-") {
ps.next();
const id = this.getIdentifier(ps);
let attr;
if (ps.currentChar === ".") {
ps.next();
attr = this.getIdentifier(ps);
}
let args;
if (ps.currentChar === "(") {
args = this.getCallArguments(ps);
}
return new TermReference(id, attr, args);
}
if (ps.isIdentifierStart()) {
const id = this.getIdentifier(ps);
if (ps.currentChar === "(") {
// It's a Function. Ensure it's all upper-case.
if (!/^[A-Z][A-Z0-9_-]*$/.test(id.name)) {
throw new ParseError("E0008");
}
let args = this.getCallArguments(ps);
return new FunctionReference(id, args);
}
let attr;
if (ps.currentChar === ".") {
ps.next();
attr = this.getIdentifier(ps);
}
return new MessageReference(id, attr);
}
throw new ParseError("E0028");
}
getCallArgument(ps) {
const exp = this.getInlineExpression(ps);
ps.skipBlank();
if (ps.currentChar !== ":") {
return exp;
}
if (exp.type === "MessageReference" && exp.attribute === null) {
ps.next();
ps.skipBlank();
const value = this.getLiteral(ps);
return new NamedArgument(exp.id, value);
}
throw new ParseError("E0009");
}
getCallArguments(ps) {
const positional = [];
const named = [];
const argumentNames = new Set();
ps.expectChar("(");
ps.skipBlank();
while (true) {
if (ps.currentChar === ")") {
break;
}
const arg = this.getCallArgument(ps);
if (arg.type === "NamedArgument") {
if (argumentNames.has(arg.name.name)) {
throw new ParseError("E0022");
}
named.push(arg);
argumentNames.add(arg.name.name);
} else if (argumentNames.size > 0) {
throw new ParseError("E0021");
} else {
positional.push(arg);
}
ps.skipBlank();
if (ps.currentChar === ",") {
ps.next();
ps.skipBlank();
continue;
}
break;
}
ps.expectChar(")");
return new CallArguments(positional, named);
}
getString(ps) {
ps.expectChar("\"");
let value = "";
let ch;
while ((ch = ps.takeChar(x => x !== '"' && x !== EOL))) {
if (ch === "\\") {
value += this.getEscapeSequence(ps);
} else {
value += ch;
}
}
if (ps.currentChar === EOL) {
throw new ParseError("E0020");
}
ps.expectChar("\"");
return new StringLiteral(value);
}
getLiteral(ps) {
if (ps.isNumberStart()) {
return this.getNumber(ps);
}
if (ps.currentChar === '"') {
return this.getString(ps);
}
throw new ParseError("E0014");
}
}
function indent(content) {
return content.split("\n").join("\n ");
}
function includesNewLine(elem) {
return elem.type === "TextElement" && includes(elem.value, "\n");
}
function isSelectExpr(elem) {
return elem.type === "Placeable"
&& elem.expression.type === "SelectExpression";
}
const HAS_ENTRIES = 1;
class FluentSerializer {
constructor({ withJunk = false } = {}) {
this.withJunk = withJunk;
}
serialize(resource) {
if (resource.type !== "Resource") {
throw new Error(`Unknown resource type: ${resource.type}`);
}
let state = 0;
const parts = [];
for (const entry of resource.body) {
if (entry.type !== "Junk" || this.withJunk) {
parts.push(this.serializeEntry(entry, state));
if (!(state & HAS_ENTRIES)) {
state |= HAS_ENTRIES;
}
}
}
return parts.join("");
}
serializeEntry(entry, state = 0) {
switch (entry.type) {
case "Message":
return serializeMessage(entry);
case "Term":
return serializeTerm(entry);
case "Comment":
if (state & HAS_ENTRIES) {
return `\n${serializeComment(entry, "#")}\n`;
}
return `${serializeComment(entry, "#")}\n`;
case "GroupComment":
if (state & HAS_ENTRIES) {
return `\n${serializeComment(entry, "##")}\n`;
}
return `${serializeComment(entry, "##")}\n`;
case "ResourceComment":
if (state & HAS_ENTRIES) {
return `\n${serializeComment(entry, "###")}\n`;
}
return `${serializeComment(entry, "###")}\n`;
case "Junk":
return serializeJunk(entry);
default :
throw new Error(`Unknown entry type: ${entry.type}`);
}
}
}
function serializeComment(comment, prefix = "#") {
const prefixed = comment.content.split("\n").map(
line => line.length ? `${prefix} ${line}` : prefix
).join("\n");
// Add the trailing newline.
return `${prefixed}\n`;
}
function serializeJunk(junk) {
return junk.content;
}
function serializeMessage(message) {
const parts = [];
if (message.comment) {
parts.push(serializeComment(message.comment));
}
parts.push(`${message.id.name} =`);
if (message.value) {
parts.push(serializePattern(message.value));
}
for (const attribute of message.attributes) {
parts.push(serializeAttribute(attribute));
}
parts.push("\n");
return parts.join("");
}
function serializeTerm(term) {
const parts = [];
if (term.comment) {
parts.push(serializeComment(term.comment));
}
parts.push(`-${term.id.name} =`);
parts.push(serializePattern(term.value));
for (const attribute of term.attributes) {
parts.push(serializeAttribute(attribute));
}
parts.push("\n");
return parts.join("");
}
function serializeAttribute(attribute) {
const value = indent(serializePattern(attribute.value));
return `\n .${attribute.id.name} =${value}`;
}
function serializePattern(pattern) {
const content = pattern.elements.map(serializeElement).join("");
const startOnNewLine =
pattern.elements.some(isSelectExpr) ||
pattern.elements.some(includesNewLine);
if (startOnNewLine) {
return `\n ${indent(content)}`;
}
return ` ${content}`;
}
function serializeElement(element) {
switch (element.type) {
case "TextElement":
return element.value;
case "Placeable":
return serializePlaceable(element);
default:
throw new Error(`Unknown element type: ${element.type}`);
}
}
function serializePlaceable(placeable) {
const expr = placeable.expression;
switch (expr.type) {
case "Placeable":
return `{${serializePlaceable(expr)}}`;
case "SelectExpression":
// Special-case select expression to control the whitespace around the
// opening and the closing brace.
return `{ ${serializeExpression(expr)}}`;
default:
return `{ ${serializeExpression(expr)} }`;
}
}
function serializeExpression(expr) {
switch (expr.type) {
case "StringLiteral":
return `"${expr.value}"`;
case "NumberLiteral":
return expr.value;
case "VariableReference":
return `$${expr.id.name}`;
case "TermReference": {
let out = `-${expr.id.name}`;
if (expr.attribute) {
out += `.${expr.attribute.name}`;
}
if (expr.arguments) {
out += serializeCallArguments(expr.arguments);
}
return out;
}
case "MessageReference": {
let out = expr.id.name;
if (expr.attribute) {
out += `.${expr.attribute.name}`;
}
return out;
}
case "FunctionReference":
return `${expr.id.name}${serializeCallArguments(expr.arguments)}`;
case "SelectExpression": {
let out = `${serializeExpression(expr.selector)} ->`;
for (let variant of expr.variants) {
out += serializeVariant(variant);
}
return `${out}\n`;
}
case "Placeable":
return serializePlaceable(expr);
default:
throw new Error(`Unknown expression type: ${expr.type}`);
}
}
function serializeVariant(variant) {
const key = serializeVariantKey(variant.key);
const value = indent(serializePattern(variant.value));
if (variant.default) {
return `\n *[${key}]${value}`;
}
return `\n [${key}]${value}`;
}
function serializeCallArguments(expr) {
const positional = expr.positional.map(serializeExpression).join(", ");
const named = expr.named.map(serializeNamedArgument).join(", ");
if (expr.positional.length > 0 && expr.named.length > 0) {
return `(${positional}, ${named})`;
}
return `(${positional || named})`;
}
function serializeNamedArgument(arg) {
const value = serializeExpression(arg.value);
return `${arg.name.name}: ${value}`;
}
function serializeVariantKey(key) {
switch (key.type) {
case "Identifier":
return key.name;
case "NumberLiteral":
return key.value;
default:
throw new Error(`Unknown variant key type: ${key.type}`);
}
}
/*
* Abstract Visitor pattern
*/
class Visitor {
visit(node) {
if (Array.isArray(node)) {
node.forEach(child => this.visit(child));
return;
}
if (!(node instanceof BaseNode)) {
return;
}
const visit = this[`visit${node.type}`] || this.genericVisit;
visit.call(this, node);
}
genericVisit(node) {
for (const propname of Object.keys(node)) {
this.visit(node[propname]);
}
}
}
/*
* Abstract Transformer pattern
*/
class Transformer extends Visitor {
visit(node) {
if (!(node instanceof BaseNode)) {
return node;
}
const visit = this[`visit${node.type}`] || this.genericVisit;
return visit.call(this, node);
}
genericVisit(node) {
for (const propname of Object.keys(node)) {
const propvalue = node[propname];
if (Array.isArray(propvalue)) {
const newvals = propvalue
.map(child => this.visit(child))
.filter(newchild => newchild !== undefined);
node[propname] = newvals;
}
if (propvalue instanceof BaseNode) {
const new_val = this.visit(propvalue);
if (new_val === undefined) {
delete node[propname];
} else {
node[propname] = new_val;
}
}
}
return node;
}
}
const visitor = ({
Visitor: Visitor,
Transformer: Transformer
});
/* eslint object-shorthand: "off",
comma-dangle: "off",
no-labels: "off" */
this.EXPORTED_SYMBOLS = [
...Object.keys({
FluentParser,
FluentSerializer,
}),
...Object.keys(ast),
...Object.keys(visitor),
];
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