# 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("Gaborcsardi/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" ))
``````
``````#> [1] 2
``````
``````cyclocomp(quote( while (condition) { loop } ))
``````
``````#> [1] 3
``````
``````cyclocomp(
function(arg) { calulate(this); and(that) }
)
``````
``````#> [1] 1
``````
``````cyclocomp(ls)
``````
``````#> [1] 10
``````
``````cyclocomp(cyclocomp)
``````
``````#> [1] 1
``````

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

``````cyclocomp(quote({
if (condition) this
}))
``````
``````#> [1] 2
``````

An `if` with an `else` branch:

``````cyclocomp(quote({
if (condition) this else that
}))
``````
``````#> [1] 2
``````

Loops:

``````cyclocomp(quote({
for (var in seq) expr
}))
``````
``````#> [1] 3
``````
``````cyclocomp(quote({
while (cond) expr
}))
``````
``````#> [1] 3
``````
``````cyclocomp(quote({
repeat expr
}))
``````
``````#> [1] 2
``````

`break` and `next` statements add to the complexity:

``````cyclocomp(quote({
for (var in seq) {
this
break
that
}
}))
``````
``````#> [1] 4
``````
``````cyclocomp(quote({
for (var in seq) {
this
next
that
}
}))
``````
``````#> [1] 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)
``````
``````#> [1] 4
``````