| Title: | Parse Data of 'R' Code as an 'XML' Tree |
| Version: | 1.0.5 |
| Author: | Gábor Csárdi |
| Maintainer: | Gábor Csárdi <csardi.gabor@gmail.com> |
| Description: | Convert the output of 'utils::getParseData()' to an 'XML' tree, that one can search via 'XPath', and easier to manipulate in general. |
| License: | MIT + file LICENSE |
| LazyData: | true |
| URL: | https://github.com/r-lib/xmlparsedata#readme |
| BugReports: | https://github.com/r-lib/xmlparsedata/issues |
| RoxygenNote: | 6.0.1 |
| Suggests: | covr, testthat, xml2 |
| Depends: | R (≥ 3.0.0) |
| Encoding: | UTF-8 |
| NeedsCompilation: | no |
| Packaged: | 2021-03-06 10:52:40 UTC; gaborcsardi |
| Repository: | CRAN |
| Date/Publication: | 2021-03-06 11:10:02 UTC |
Parse Data of R Code as an 'XML' Tree
Description
Convert the output of 'utils::getParseData()' to an 'XML' tree, that is searchable and easier to manipulate in general.
Convert R parse data to XML
Description
In recent R versions the parser can attach source code location
information to the parsed expressions. This information is often
useful for static analysis, e.g. code linting. It can be accessed
via the getParseData function.
Usage
xml_parse_data(x, includeText = NA, pretty = FALSE)
Arguments
x |
an expression returned from |
includeText |
logical; whether to include the text of parsed items in the result |
pretty |
Whether to pretty-indent the XML output. It has a small overhead which probably only matters for very large source files. |
Details
xml_parse_data converts this information to an XML tree.
The R parser's token names are preserved in the XML as much as
possible, but some of them are not valid XML tag names, so they are
renamed, see the xml_parse_token_map vector for the
mapping.
The top XML tag is <exprlist>, which is a list of
expressions, each expression is an <expr> tag. Each tag
has attributes that define the location: line1, col1,
line2, col2. These are from the getParseData
data frame column names.
See an example below. See also the README at
https://github.com/r-lib/xmlparsedata#readme
for examples on how to search the XML tree with the xml2 package
and XPath expressions.
Note that 'xml_parse_data()' silently drops all control characters (0x01-0x1f) from the input, except horizontal tab (0x09) and newline (0x0a), because they are invalid in XML 1.0.
Value
An XML string representing the parse data. See details below.
See Also
xml_parse_token_map for the token names.
https://github.com/r-lib/xmlparsedata#readme for more
information and use cases.
Examples
code <- "function(a = 1, b = 2) {\n a + b\n}\n"
expr <- parse(text = code, keep.source = TRUE)
# The base R way:
getParseData(expr)
cat(xml_parse_data(expr, pretty = TRUE))
Map token names of the R parser to token names in
xml_parse_data
Description
Some of the R token names are not valid XML tag names,
so xml_parse_data needs to replace them to create a
valid XML file.
Usage
xml_parse_token_map
Format
An object of class character of length 20.