diffobj (version 0.1.2)

[,Diff,numeric,missing,missing-method: Subsetting Methods for Diff Objects

Description

Methods to subset the character representation of the diff output. The subsetting bears no link to the line numbers in the diffs, only to the actual displayed diff.

Usage

"["(x, i)
"head"(x, n, ...)
"tail"(x, n, ...)

Arguments

x

Diff object

i

subsetting index, must be numeric

n

integer(1L), the size for the resulting object

...

unused, for compatibility with generics

Value

Diff object with subsetting indices recorded for use by show

Details

[ only supports numeric indices, and returns without error if you specify out of bound indices. If you apply multiple subsetting methods they will be applied in the following order irrespective of what order you actually specify them in: [, then head, then tail. If you use the same subsetting method multiple times on the same object, the last call will define the outcome.

These methods are implemented by storing the chosen indices in the Diff object and using them to subset the as.character output. This mechanism explains the seemingly odd behavior documented above.