parseFhirPath function

ParserList parseFhirPath(String pathExpression)

Parse a FHIRPath for repeated use with different inputs later.

Implementation

ParserList parseFhirPath(String pathExpression) {
  try {
    final ast = lexer().parse(pathExpression).value;
    if (ast is ParserList) {
      if (ast.isEmpty) {
        return ast;
      } else {
        // Check for combination of IdentifierParser followed by ParenthesisParser
        // This indicates invalid function name
        if (ast.value.length > 1) {
          for (int i = 0; i < ast.value.length - 1; i++) {
            if ((ast.value[i] is IdentifierParser) &&
                (ast.value[i + 1] is ParenthesesParser)) {
              final String functionName =
                  (ast.value[i] as IdentifierParser).value;
              throw FhirPathInvalidExpressionException(
                  'Unknown function: $functionName',
                  pathExpression: pathExpression);
            }
          }
        }

        return ast;
      }
    } else {
      throw FhirPathInvalidExpressionException(
          'Parsing did not result in ParserList',
          pathExpression: pathExpression);
    }
  } catch (error) {
    if (error is ParserException) {
      throw FhirPathInvalidExpressionException(
        'Expression could not be parsed: ${error.message}',
        pathExpression: pathExpression,
        offset: error.offset,
        cause: error,
      );
    } else {
      rethrow;
    }
  }
}