cyclocomp

Cyclomatic Complexity of R Code

Cyclomatic complexity is a software metric (measurement), used to indicate the complexity of a program. It is a quantitative measure of the number of linearly independent paths through a program's source code. It was developed by Thomas J. McCabe, Sr. in 1976.

Installation

devtools::install_github("MangoTheCat/cyclocomp")

Usage

library(cyclocomp)

cyclocomp takes quoted R expressions or function objects, and returns a single integer, the cyclomatic complexity of the expression or function.

cyclocomp(quote( if (condition) "foo" else "bar" ))
#>  2
cyclocomp(quote( while (condition) { loop } ))
#>  3
cyclocomp(
function(arg) { calulate(this); and(that) }
)
#>  1
cyclocomp(ls)
#>  10
cyclocomp(cyclocomp)
#>  1

Some more examples for the R control structures. A simple if first:

cyclocomp(quote({
if (condition) this
}))
#>  2

An if with an else branch:

cyclocomp(quote({
if (condition) this else that
}))
#>  2

Loops:

cyclocomp(quote({
for (var in seq) expr
}))
#>  3
cyclocomp(quote({
while (cond) expr
}))
#>  3
cyclocomp(quote({
repeat expr
}))
#>  2

break and next statements add to the complexity:

cyclocomp(quote({
for (var in seq) {
this
break
that
}
}))
#>  4
cyclocomp(quote({
for (var in seq) {
this
next
that
}
}))
#>  4

Multiple (explicit or implicit) return calls also add to the complexity:

f <- function(arg) {
if (arg) {
return("this")
} else {
return("that")
}
"Otherwise return me"
}
cyclocomp(f)
#>  4