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trySingleExpression() -> singleExpression()

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This commit is contained in:
Natalie Weizenbaum 2016-05-24 09:53:56 -07:00
parent fcb0b7d29e
commit 5308fcfb05
1 changed files with 23 additions and 25 deletions
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48
lib/src/parser.dart
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@ -276,21 +276,14 @@ class Parser {
// ## Expressions
Expression _expression() {
var expression = _tryExpression();
if (expression == null) _scanner.error("Expected expression.");
return expression;
}
Expression _tryExpression() {
var hadComma = false;
var start = _scanner.state;
var commaExpressions = <Expression>[];
while (true) {
var spaceExpressions = <Expression>[];
while (true) {
var next = _trySingleExpression();
if (next == null) break;
spaceExpressions.add(next);
if (!_isExpressionStart(_scanner.peekChar())) break;
spaceExpressions.add(_singleExpression());
_ignoreComments();
}
@ -308,15 +301,17 @@ class Parser {
_ignoreComments();
}
if (commaExpressions.isEmpty) return null;
if (commaExpressions.isEmpty) _scanner.error("Expected expression.");
if (!hadComma) return commaExpressions.single;
return new ListExpression(commaExpressions, ListSeparator.comma,
span: _scanner.spanFrom(start));
}
Expression _trySingleExpression() {
Expression _singleExpression() {
var first = _scanner.peekChar();
switch (first) {
// Note: when adding a new case, make sure it's reflected in
// [_isExpressionStart].
case $lparen: return _parentheses();
case $slash: return _unaryOperator();
case $dot: return _number();
@ -339,21 +334,20 @@ class Parser {
case $minus:
var next = _scanner.peekChar(1);
if (_isDigit(next) || next == $dot) return _number();
if (_isNameStart(next) || next == $dash || next == $backslash) {
return _identifierLike();
}
if (_lookingAtInterpolatedIdentifier()) return _identifierLike();
return _unaryOperator();
default:
if (first == null) return null;
if (first == null) _scanner.error("Expected expression.");
if (_isNameStart(first) || first == $backslash) {
return _identifierLike();
}
if (_isDigit(first)) return _number();
return null;
_scanner.error("Expected expression");
throw "Unreachable";
}
}
@ -586,6 +580,13 @@ class Parser {
(character >= $a && character <= $f) ||
(character >= $A && character <= $F);
bool _isExpressionStart(int character) =>
character == $lparen || character == $slash || character == $dot ||
character == $lbracket || character == $single_quote ||
character == $double_quote || character == $hash || character == $plus ||
character == $minus || character == $backslash ||
_isNameStart(character) || _isDigit(character);
int _asHex(int character) {
if (character <= $9) return character - $0;
if (character <= $F) return 10 + character - $A;
@ -634,22 +635,19 @@ class Parser {
// ## Utilities
/// Based on [the CSS algorithm][], but also considers interpolation to be
/// valid in an identifier.
/// This is based on [the CSS algorithm][], but it assumes all backslashes
/// start escapes and it considers interpolation to be valid in an identifier.
///
/// [the CSS algorithm]: https://drafts.csswg.org/css-syntax-3/#would-start-an-identifier
bool _lookingAtInterpolatedIdentifier() {
var first = _scanner.peekChar();
if (_isNameStart(first)) return true;
if (first == $backslash) return !_isNewline(_scanner.peekChar(1));
if (_isNameStart(first) || first == $backslash) return true;
if (first == $hash) return _scanner.peekChar(1) == $lbrace;
if (first != $dash) return false;
var second = _scanner.peekChar();
if (_isNameStart(second)) return true;
if (second == $hash) return _scanner.peekChar(2) == $lbrace;
return second == $backslash && !_isNewline(_scanner.peekChar(2));
if (_isNameStart(second) || second == $backslash) return true;
return second == $hash && _scanner.peekChar(2) == $lbrace;
}
String _rawText(void consumer()) {