Build and Query R or Package News Information

Description

Build and query the news for R or add-on packages.

Usage

news(query, package = "R", lib.loc = NULL, format = NULL, 
     reader = NULL, db = NULL)

Arguments

Details

If package is "R" (default), readNEWS in package tools is used to build a news db from the R ‘NEWS’ file. Otherwise, if the given add-on package can be found in the given libraries and has a ‘NEWS’ file, it is attempted to read the package news in structured form. The ‘NEWS’ files in add-on packages use a variety of different formats; the default news reader should be capable to extract individual news entries from a majority of packages from the standard repositories, which use (slight variations of) the following format:

• Entries are grouped according to version, with version header Changes in version at the beginning of a line, followed by a version number, optionally followed by an ISO 8601 (%Y-%m-%d, see strptime) format date, possibly parenthesized.
• Entries may be grouped according to category, with a category header (different from a version header) starting at the beginning of a line.
• Entries are written as itemize-type lists, using one of o, *, - or + as item tag. Entries must be indented, and ideally use a common indentation for the item texts.

Additional formats and readers may be supported in the future.

The news db built is a character data frame inheriting from "news_db" with variables Version, Category, Date and Text, where the last contains the entry texts read, and the other variables may be NA if they were missing or could not be determined.

Using query, one can select news entries from the db. If missing or NULL, the complete db is returned. Otherwise, query should be an expression involving (a subset of) the variables Version, Category, Date and Text, and when evaluated within the db returning a logical vector with length the number of entries in the db. The entries for which evaluation gave TRUE are selected. When evaluating, Version and Date are coerced to numeric_version and Date objects, respectively, so that the comparison operators for these classes can be employed.

Value

An data frame inheriting from class "news_db".

Examples

## Build a db of all R news entries.
db <- news()
## Bug fixes with PR number in 2.9.0.
news(Version == "2.9.0" & grepl("^BUG", Category) & grepl("PR#", Text),
     db = db)
## Entries with version >= 2.8.1 (including "2.8.1 patched"):
table(news(Version >= "2.8.1", db = db)$Version)