public _tryParseCustomPropertyDeclaration()

in src/parser/cssParser.ts [478:530]
48 lines of code
16 McCabe index (conditional complexity)

	public _tryParseCustomPropertyDeclaration(stopTokens?: TokenType[]): nodes.CustomPropertyDeclaration | null {
		if (!this.peekRegExp(TokenType.Ident, /^--/)) {
			return null;
		}
		const node = this.create(nodes.CustomPropertyDeclaration);
		if (!node.setProperty(this._parseProperty())) {
			return null;
		}

		if (!this.accept(TokenType.Colon)) {
			return this.finish(node, ParseError.ColonExpected, [TokenType.Colon]);
		}
		if (this.prevToken) {
			node.colonPosition = this.prevToken.offset;
		}

		const mark = this.mark();
		if (this.peek(TokenType.CurlyL)) {
			// try to parse it as nested declaration
			const propertySet = this.create(nodes.CustomPropertySet);
			const declarations = this._parseDeclarations(this._parseRuleSetDeclaration.bind(this));
			if (propertySet.setDeclarations(declarations) && !declarations.isErroneous(true)) {
				propertySet.addChild(this._parsePrio());
				if (this.peek(TokenType.SemiColon)) {
					this.finish(propertySet);
					node.setPropertySet(propertySet);
					node.semicolonPosition = this.token.offset; // not part of the declaration, but useful information for code assist
					return this.finish(node);
				}
			}
			this.restoreAtMark(mark);
		}

		// try to parse as expression
		const expression = this._parseExpr();
		if (expression && !expression.isErroneous(true)) {
			this._parsePrio();
			if (this.peekOne(...(stopTokens || []), TokenType.SemiColon, TokenType.EOF)) {
				node.setValue(expression);
				if (this.peek(TokenType.SemiColon)) {
					node.semicolonPosition = this.token.offset; // not part of the declaration, but useful information for code assist
				}
				return this.finish(node);
			}
		}
		this.restoreAtMark(mark);
		node.addChild(this._parseCustomPropertyValue(stopTokens));
		node.addChild(this._parsePrio());
		if (isDefined(node.colonPosition) && this.token.offset === node.colonPosition + 1) {
			return this.finish(node, ParseError.PropertyValueExpected);
		}
		return this.finish(node);
	}