matchConcordance {tools}R Documentation

Concordance between source and target lines


The Rd parser records locations in ‘.Rd’ files from which components of the file are read. Output generators Rd2HTML and Rd2latex can output information about these locations as “concordances” between source and output lines.

matchConcordance converts from output locations to source locations. The "Rconcordance" method of as.character produces strings to embed in output files, and the default method of as.Rconcordance converts these back to objects that can be interpreted by matchConcordance.


matchConcordance(linenum, concordance)
## S3 method for class 'Rconcordance'
as.character(x, targetfile = "", ...)
as.Rconcordance(x, ...)
followConcordance(concordance, prevConcordance)



One or more line numbers being queried.


The concordance data for the file containing the lines: an object of class "Rconcordance".


A concordance object retrieved from the current file.


The output filename.


The object to convert: for as.character, an "Rconcordance" object; for as.concordance, a character vector which contains as.character output, typically in comments.


Further arguments passed to other methods.


The correspondence between target lines and source lines in Rd file conversion is not one to one. Often a single source line can lead to the generation of multiple output lines, and sometimes more than one source line triggers output on the same output line.

matchConcordance converts from target lines to source lines. This can be used to help in understanding how particular output lines depend on the source, e.g. when an error is found in the output file. When more than one line contributes to the output, the last one will be returned.

The "Rconcordance" method of as.character converts a concordance object to strings suitable for embedding (e.g. in comments) in an output file.

The default method of as.Rconcordance searches for strings matching the pattern of as.character.Rconcordance output, then converts those lines back to a single concordance.

followConcordance is used when a file is transformed more than once. The first transformation records a concordance in the file which is read as prevConcordance. followConcordance chains this with the current concordance, relating the final result to the original source.

There are 3 kinds of objects used to hold concordances.

Objects of class "activeConcordance" are internal to tools; they are used by Rd2HTML and Rd2latex while building the output file and saving links to the source file.

Objects of class "Rconcordance" are visible to users. They are list objects with the following three fields:


The number of lines of output before the first one corresponding to this concordance.


For each line of output after the offset, the corresponding input file line number. There may be more lines of output than the length of srcLine, in which case nothing can be inferred about the source of those lines.


A vector of filenames of length 1 or the same length as srcLine giving the source file(s) for each output line.

Concordance strings are produced by the "Rconcordance" method of as.character; they are simply character vectors encoding the concordance data. The default method of the as.concordance generic function converts them to "Rconcordance" objects.


matchConcordance returns a character array with one row per input linenum entry and two columns, "srcFile" and "srcLine".

For the "Rconcordance" method of as.character, a character vector used (e.g. in Sweave) to embed the concordance in a file.

For as.concordance, an "Rconcordance" object, or NULL if no concordance strings are found.


Duncan Murdoch

See Also

Rd2HTML, Rd2latex

[Package tools version 4.4.1 Index]