mirror of
https://github.com/danog/dart-sass.git
synced 2025-01-22 05:41:14 +01:00
Some parser junk.
This commit is contained in:
Natalie Weizenbaum
parent
cf28c7ed20
commit
60e2e66b72
13
lib/src/expression/interpolation.dart
Normal file
13
lib/src/expression/interpolation.dart
Normal file
@ -0,0 +1,13 @@
|
||||
// Copyright 2016 Google Inc. Use of this source code is governed by an
|
||||
// MIT-style license that can be found in the LICENSE file or at
|
||||
// https://opensource.org/licenses/MIT.
|
||||
|
||||
class InterpolationExpression {
|
||||
/// If this contains no interpolation, returns the plain text it contains.
|
||||
///
|
||||
/// Otherwise, returns `null`.
|
||||
String get asPlain;
|
||||
|
||||
InterpolationExpression(List/* <String|Expression> */ contents,
|
||||
{SourceSpan span});
|
||||
}
|
||||
366
lib/src/parser.dart
Normal file
366
lib/src/parser.dart
Normal file
@ -0,0 +1,366 @@
|
||||
// Copyright 2016 Google Inc. Use of this source code is governed by an
|
||||
// MIT-style license that can be found in the LICENSE file or at
|
||||
// https://opensource.org/licenses/MIT.
|
||||
|
||||
import 'package:string_scanner/string_scanner.dart';
|
||||
|
||||
class Parser {
|
||||
final SpanScanner _scanner;
|
||||
|
||||
Parser(String contents, {url})
|
||||
: _scanner = new SpanScanner(contents, url: url);
|
||||
|
||||
// Conventions:
|
||||
//
|
||||
// * All statement and expression functions consume through following
|
||||
// whitespace, including comments.
|
||||
//
|
||||
// * A function will return `null` if it fails to match iff it begins with
|
||||
// "try".
|
||||
|
||||
// ## Statements
|
||||
|
||||
StylesheetNode parse() {
|
||||
var start = _scanner.state;
|
||||
var children = <Node>[];
|
||||
do {
|
||||
children.addAll(_comments());
|
||||
var child = _tryVariableDeclaration() ??
|
||||
_tryAtRule() ??
|
||||
_tryDeclaration();
|
||||
if (child != null) children.add(child);
|
||||
} while (_scanner.scan(';'));
|
||||
|
||||
_scanner.expectDone();
|
||||
return new StylesheetNode(children, span: _scanner.spanFrom(start));
|
||||
}
|
||||
|
||||
VariableDeclarationNode _tryVariableDeclaration() {
|
||||
if (!_scanChar($dollar)) return null;
|
||||
|
||||
var start = _scanner.state;
|
||||
var name = _rawIdentifier();
|
||||
_ignoreComments();
|
||||
_expectChar($colon);
|
||||
_ignoreComments();
|
||||
|
||||
var expression = _expression();
|
||||
|
||||
var guarded = false;
|
||||
var global = false;
|
||||
while (_scanChar($exclamation)) {
|
||||
var flagStart = _scanner.position - 1;
|
||||
var flag = _rawIdentifier();
|
||||
if (flag == 'default') {
|
||||
guarded = true;
|
||||
} else if (flag == 'global') {
|
||||
global = true;
|
||||
} else {
|
||||
_scanner.error("Invalid flag name.",
|
||||
position: flagStart,
|
||||
length: _scanner.position - flagStart);
|
||||
}
|
||||
|
||||
_ignoreComments();
|
||||
}
|
||||
|
||||
return new VariableDeclarationNode(name, expression,
|
||||
guarded: guarded, global: global, span: _scanner.spanFrom(start));
|
||||
}
|
||||
|
||||
/// Consumes whitespace if available and returns any comments it contained.
|
||||
List<Node> _comments() {
|
||||
var nodes = [];
|
||||
while (true) {
|
||||
_whitespace();
|
||||
|
||||
var silent = _trySilentComment();
|
||||
if (silent != null) {
|
||||
nodes.add(silent);
|
||||
continue;
|
||||
}
|
||||
|
||||
var silent = _tryLoudComment();
|
||||
if (silent != null) {
|
||||
nodes.add(silent);
|
||||
continue;
|
||||
}
|
||||
|
||||
return nodes;
|
||||
}
|
||||
}
|
||||
|
||||
// ## Expressions
|
||||
|
||||
Expressions _expression() {
|
||||
var expression = _tryExpression();
|
||||
if (expression == null) _scanner.error("Expected expression.");
|
||||
return expression;
|
||||
}
|
||||
|
||||
Expression _tryExpression() {
|
||||
var hadComma = false;
|
||||
var commaStart = _scanner.state;
|
||||
var commaExpressions = <Expression>[];
|
||||
while (true) {
|
||||
var spaceExpressions = <Expression>[];
|
||||
while (true) {
|
||||
var next = _trySingleExpression();
|
||||
if (next == null) break;
|
||||
spaceExpressions.add(next);
|
||||
}
|
||||
|
||||
if (spaceExpressions.isEmpty) {
|
||||
break;
|
||||
} else if (spaceExpressions.length == 1) {
|
||||
commaExpressions.add(spaceExpressions.single);
|
||||
} else {
|
||||
commaExpressions.add(
|
||||
new ListExpression(spaceExpressions, ListSeparator.space));
|
||||
}
|
||||
|
||||
if (!_scanChar($comma)) break;
|
||||
hadComma = true;
|
||||
_ignoreComments();
|
||||
}
|
||||
|
||||
if (commaExpressions.isEmpty) return null;
|
||||
if (!hadComma) return commaExpressions.single;
|
||||
return new ListExpression(commaExpressions, ListSeparator.comma,
|
||||
span: _scanner.spanFrom(start));
|
||||
}
|
||||
|
||||
Expression _trySingleExpression() {
|
||||
var first = _scanner.peekChar();
|
||||
switch (first) {
|
||||
case $lparen: return _parentheses();
|
||||
case $slash: return _unaryOperator();
|
||||
case $dot: return _number();
|
||||
case $lbracket: return _bracketList();
|
||||
|
||||
case $single_quote:
|
||||
case $double_quote:
|
||||
return _string();
|
||||
|
||||
case $hash:
|
||||
if (_scanner.peekChar(1) == $lbrace) return _identifierLike();
|
||||
return _hexColor();
|
||||
|
||||
case $plus:
|
||||
var next = _scanner.peekChar(1);
|
||||
if (_isDigit(next) || next == $dot) return _number();
|
||||
|
||||
return _unaryOperator();
|
||||
|
||||
case $minus:
|
||||
var next = _scanner.peekChar(1);
|
||||
if (_isDigit(next) || next == $dot) return _number();
|
||||
|
||||
if (_isNameStart(next) || next == $hyphen || next == $backslash) {
|
||||
return _identifierLike();
|
||||
}
|
||||
|
||||
return _unaryOperator();
|
||||
|
||||
default:
|
||||
if (_isNameStart(first) || first == $backslash) {
|
||||
return _identifierLike();
|
||||
}
|
||||
if (_isDigit(first)) return _number();
|
||||
return null;
|
||||
}
|
||||
}
|
||||
|
||||
Expression _identifierLike() {
|
||||
// TODO: url(), functions
|
||||
return new IdentifierExpression(_identifier());
|
||||
}
|
||||
|
||||
// ## Tokens
|
||||
|
||||
void _ignoreComments() {
|
||||
do {
|
||||
_whitespace();
|
||||
} while (_trySilentComment() != null || _tryLoudComment() != null);
|
||||
}
|
||||
|
||||
Node _trySilentComment() {
|
||||
var start = _scanner.state;
|
||||
while (_scanner.scan("//")) {
|
||||
while (!_scanner.isDone && !_isNewline(_scanner.readChar())) {}
|
||||
if (_scanner.isDone) return node;
|
||||
_whitespace();
|
||||
}
|
||||
|
||||
if (_scanner.position == start.position) return null;
|
||||
|
||||
return new CommentNode(_scanner.substring(start.position),
|
||||
silent: true,
|
||||
span: _scanner.spanFrom(start));
|
||||
}
|
||||
|
||||
Node _tryLoudComment() {
|
||||
var start = _scanner.state;
|
||||
while (_scanner.scan("/*")) {
|
||||
do {
|
||||
while (_scanner.readChar() != $asterisk) {}
|
||||
} while (_scanner.readChar() != $slash);
|
||||
}
|
||||
|
||||
if (_scanner.position == start.position) return null;
|
||||
|
||||
return new CommentNode(_scanner.substring(start.position),
|
||||
silent: false,
|
||||
span: _scanner.spanFrom(start));
|
||||
}
|
||||
|
||||
void _whitespace() {
|
||||
while (!_scanner.isDone && _isWhitespace(_scanner.peekChar())) {
|
||||
_scanner.readChar();
|
||||
}
|
||||
}
|
||||
|
||||
InterpolationExpression _identifier() {
|
||||
var start = _scanner.start;
|
||||
var contents = [];
|
||||
var text = new StringBuffer();
|
||||
|
||||
while (_scanChar($hyphen)) {
|
||||
text.writeCharCode($hyphen);
|
||||
}
|
||||
|
||||
var first = _scanner.peekChar();
|
||||
if (first == null) {
|
||||
_scanner.error("Expected identifier.");
|
||||
} else if (_isNameStart(first)) {
|
||||
text.writeCharCode(_scanner.readChar());
|
||||
} else if (first == $backslash) {
|
||||
text.writeCharCode(_escape());
|
||||
} else if (first == $hash) {
|
||||
if (!text.isEmpty) contents.add(text.toString());
|
||||
text.clear();
|
||||
contents.add(_interpolation());
|
||||
}
|
||||
|
||||
while (true) {
|
||||
var next = _scanner.peekChar();
|
||||
if (next == null) {
|
||||
break;
|
||||
} else if (next == $_ || next == $- || _isAlphabetic(next) ||
|
||||
_isDigit(next) || next >= 0x0080) {
|
||||
text.writeCharCode(_scanner.readChar());
|
||||
} else if (next == $backslash) {
|
||||
text.writeCharCode(_escape());
|
||||
} else if (next == $hash) {
|
||||
if (!text.isEmpty) contents.add(text.toString());
|
||||
text.clear();
|
||||
contents.add(_interpolation());
|
||||
} else {
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
return new InterpolationExpression(
|
||||
contents, span: _scanner.spanFrom(start));
|
||||
}
|
||||
|
||||
String _rawIdentifier() {
|
||||
var text = new StringBuffer();
|
||||
while (_scanChar($hyphen)) {
|
||||
text.writeCharCode($hyphen);
|
||||
}
|
||||
|
||||
var first = _scanner.peekChar();
|
||||
if (first == null) {
|
||||
_scanner.error("Expected identifier.");
|
||||
} else if (_isNameStart(first)) {
|
||||
text.writeCharCode(_scanner.readChar());
|
||||
} else if (first == $backslash) {
|
||||
text.writeCharCode(_escape());
|
||||
} else {
|
||||
_scanner.error("Expected identifier.");
|
||||
}
|
||||
|
||||
while (true) {
|
||||
var next = _scanner.peekChar();
|
||||
if (next == null) {
|
||||
break;
|
||||
} else if (next == $_ || next == $- || _isAlphabetic(next) ||
|
||||
_isDigit(next) || next >= 0x0080) {
|
||||
text.writeCharCode(_scanner.readChar());
|
||||
} else if (next == $backslash) {
|
||||
text.writeCharCode(_escape());
|
||||
} else {
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
return text.toString();
|
||||
}
|
||||
|
||||
// ## Characters
|
||||
|
||||
bool _isWhitespace(int character) =>
|
||||
character == $space || character == $tab || _isNewline(character);
|
||||
|
||||
bool _isNewline(int character) =>
|
||||
character == $lf || character == $cr || character == $ff;
|
||||
|
||||
bool _isAlphabetic(int character) =>
|
||||
(character >= $a && character <= $z) ||
|
||||
(character >= $A && character <= $Z);
|
||||
|
||||
bool _isDigit(int character) => character >= $0 && character <= $9;
|
||||
|
||||
bool _isNameStart(int character) =>
|
||||
character == $_ || _isAlphabetic(character) || character >= 0x0080;
|
||||
|
||||
bool _isHex(int character) =>
|
||||
_isDigit(character) ||
|
||||
(character >= $a && character <= $f) ||
|
||||
(character >= $A && character <= $F);
|
||||
|
||||
int _asHex(int character) {
|
||||
if (char <= $9) return char - $0;
|
||||
if (char <= $F) return 10 + char - $A;
|
||||
return 10 + char - $A;
|
||||
}
|
||||
|
||||
int _escape() {
|
||||
// See https://drafts.csswg.org/css-syntax-3/#consume-escaped-code-point.
|
||||
|
||||
_expectChar($backslash);
|
||||
var first = _scanner.peekChar();
|
||||
if (first == null) {
|
||||
return 0xFFFD;
|
||||
} else if (first == $newline) {
|
||||
_scanner.error("Expected escape sequence.");
|
||||
} else if (_isHex(first)) {
|
||||
var value = 0;
|
||||
for (var i = 0; i < 6; i++) {
|
||||
if (!_isHex(_scanner.peekChar())) break;
|
||||
value = (value << 4) + _asHex(_scanner.readChar());
|
||||
}
|
||||
if (_isWhitespace(_scanner.peekChar())) _scanner.readChar();
|
||||
|
||||
if (value == 0 || (value >= 0xD800 && value <= 0xDFFF) ||
|
||||
value >= 0x10FFFF) {
|
||||
return 0xFFFD;
|
||||
} else {
|
||||
return value;
|
||||
}
|
||||
} else {
|
||||
return _scanner.readChar();
|
||||
}
|
||||
}
|
||||
|
||||
bool _scanChar(int character) {
|
||||
if (_scanner.peekChar() != character) return false;
|
||||
return _scanner.readChar();
|
||||
}
|
||||
|
||||
void _expectChar(int character) {
|
||||
if (_scanChar(character)) return;
|
||||
_sanner.expect(new String.fromCharCode(character));
|
||||
}
|
||||
}
|
||||
Loading…
x
Reference in New Issue
Block a user