Declaration? processDeclaration()

in lib/parser.dart [1739:1806]
50 lines of code
11 McCabe index (conditional complexity)

  Declaration? processDeclaration(List<DartStyleExpression> dartStyles) {
    Declaration? decl;

    var start = _peekToken.span;

    // IE7 hack of * before property name if so the property is IE7 or below.
    var ie7 = _peekKind(TokenKind.ASTERISK);
    if (ie7) {
      _next();
    }

    // IDENT ':' expr '!important'?
    if (TokenKind.isIdentifier(_peekToken.kind)) {
      var propertyIdent = identifier();

      var ieFilterProperty = propertyIdent.name.toLowerCase() == 'filter';

      _eat(TokenKind.COLON);

      var exprs = processExpr(ieFilterProperty);

      var dartComposite = _styleForDart(propertyIdent, exprs, dartStyles);

      // Handle !important (prio)
      var importantPriority = _maybeEat(TokenKind.IMPORTANT);

      decl = Declaration(propertyIdent, exprs, dartComposite, _makeSpan(start),
          important: importantPriority, ie7: ie7);
    } else if (_peekToken.kind == TokenKind.VAR_DEFINITION) {
      _next();
      Identifier? definedName;
      if (_peekIdentifier()) definedName = identifier();

      _eat(TokenKind.COLON);

      var exprs = processExpr();

      decl = VarDefinition(definedName, exprs, _makeSpan(start));
    } else if (_peekToken.kind == TokenKind.DIRECTIVE_INCLUDE) {
      // @include mixinName in the declaration area.
      var span = _makeSpan(start);
      var include = processInclude(span, eatSemiColon: false);
      decl = IncludeMixinAtDeclaration(include, span);
    } else if (_peekToken.kind == TokenKind.DIRECTIVE_EXTEND) {
      var simpleSequences = <TreeNode>[];

      _next();
      var span = _makeSpan(start);
      var selector = simpleSelector();
      if (selector == null) {
        _warning('@extends expecting simple selector name', span);
      } else {
        simpleSequences.add(selector);
      }
      if (_peekKind(TokenKind.COLON)) {
        var pseudoSelector = processPseudoSelector(_peekToken.span);
        if (pseudoSelector is PseudoElementSelector ||
            pseudoSelector is PseudoClassSelector) {
          simpleSequences.add(pseudoSelector!);
        } else {
          _warning('not a valid selector', span);
        }
      }
      decl = ExtendDeclaration(simpleSequences, span);
    }

    return decl;
  }