line_length_style {roger}

Validation of Length of Code and Comments Lines

Description

Check that the length of code and comment lines does not exceed a given limit in number of characters.

Usage

line_length_style(srcData, nchar_max = 80L)

Arguments

srcData

a list as returned by getSourceData.

nchar_max

maximum number of characters per line.

Details

Good coding practice dictates to limit line length to a value around 80 characters for readability purposes.

The line length is determined from the column number ending each line of code in the parse information. This may give unintended results if the encoding used in getParseData does not match the encoding of the script file and the latter contains non ASCII characters.

Value

Boolean. When FALSE, a message indicates the nature of the error and the faulty lines, and the returned value has the following attributes:

lines

faulty line numbers;

message

text of the error message.

Examples

## Keep parse data in non interactive sessions.
if (!interactive())
    op <- options(keep.source = TRUE)

## Valid line length
fil <- tempfile(fileext = ".R")
cat("## innocuous comment",
    "x <- 2",
    "y <- 3",
    "x + y",
    file = fil, sep = "\n")
line_length_style(getSourceData(fil))

## Limit valid line length to only 20 characters
fil <- tempfile(fileext = ".R")
cat("## no longer innocuous comment",
    "x <- 2",
    "y <- 3",
    "x + y",
    file = fil, sep = "\n")
line_length_style(getSourceData(fil), 20)