Conditions raised by zuxml

Every error zuxml raises carries a condition class, so that it can be caught by kind rather than by matching the message, which is not stable. Every class below is a subclass of zuxml_error.

Details

zuxml_invalid_argument

An argument was not usable: an x that is not a single string or a raw vector, an encoding other than UTF-8 for character input, a limit that is not a positive whole number, or a flag that is not TRUE or FALSE.

zuxml_parse_error

The input is not well-formed XML, ends too early, or references an undefined entity.

zuxml_encoding_error

The input is not valid in its encoding, or names an encoding that neither Expat nor iconv() can read.

zuxml_doctype_error

The document has a DOCTYPE declaration and allow_doctype is FALSE, or it has an internal subset, which is refused either way.

zuxml_limit_error

A resource limit was reached. The subclasses zuxml_depth_limit, zuxml_node_limit, zuxml_attr_limit, zuxml_text_limit and zuxml_memory_limit name which one. xml_serialize() raises the parent class alone when a node's text is longer than an R string can hold.

zuxml_memory_error

An allocation failed.

zuxml_cancelled

A handler stopped the parse. It can only happen through the C API, where a downstream package supplies the handler; no exported R function raises it.

A condition raised by a parse carries line, column and byte_offset, the position where the parser stopped; status, the C status's enumerator name, such as "ZUX_ERR_DEPTH_LIMIT"; and expat_code, Expat's own error code, which is NA when the failure was not Expat's. It is there for diagnostics: do not branch on it. A limit error also carries limit, the argument's name, such as "max_depth", and limit_value, the value it was given. A zuxml_invalid_argument condition carries arg, the name of the argument at fault.

Examples

tryCatch(
  xml_parse("<a><b></a>"),
  zuxml_parse_error = function(e) c(line = e$line, column = e$column)
)
#>   line column 
#>      1      8 
tryCatch(
  xml_parse("<a><b/></a>", max_depth = 1),
  zuxml_limit_error = function(e) e$limit
)
#> [1] "max_depth"