inst/pluginTemplate/Supporting_Macros/Style_Guide.md

In alteryx/jeeves: A helper for developing predictive tools in Alteryx

Alteryx R Style guide

This is a modified version of the style guide by Hadley Wickham

Notation and naming

File names

File names should be meaningful and end in .R.

# Good
fit-models.R
utility-functions.R

# Bad
foo.r
stuff.r

If files need to be run in sequence, prefix them with numbers:

0-download.R
1-parse.R
2-explore.R

Object names

"There are only two hard things in Computer Science: cache invalidation and naming things."

--- Phil Karlton

Variable names should be snake_case and function names should be camelCase. Generally, variable names should be nouns and function names should be verbs. Strive for names that are concise and meaningful (this is not easy!).

```{r, eval = FALSE}

Good

day_one day1 computeMean

Bad

firstDayOfMonth DayOne dayone djm1 compute_mean

Where possible, avoid using names of existing functions and variables. This will cause confusion for the readers of your code.

```{r, eval = FALSE}
# Bad
T <- FALSE
c <- 10
mean <- function(x) sum(x)

Syntax

Spacing

Place spaces around all infix operators (=, +, -, <-, etc.). The same rule applies when using = in function calls. Always put a space after a comma, and never before (just like in regular English).

```{r, eval = FALSE}

Good

average <- mean(feet / 12 + inches, na.rm = TRUE)

Bad

average<-mean(feet/12+inches,na.rm=TRUE)

There's a small exception to this rule: `:`, `::` and `:::` don't need spaces around them.

```{r, eval = FALSE}
# Good
x <- 1:10
base::get

# Bad
x <- 1 : 10
base :: get

Place a space before left parentheses, except in a function call.

```{r, eval = FALSE}

Good

if (debug) do(x) plot(x, y)

Bad

if(debug)do(x) plot (x, y)

Extra spacing (i.e., more than one space in a row) is ok if it improves alignment of equal signs or assignments (`<-`).

```{r, eval = FALSE}
list(
  total = a + b + c, 
  mean  = (a + b + c) / n
)

Do not place spaces around code in parentheses or square brackets (unless there's a comma, in which case see above).

```{r, eval = FALSE}

Good

if (debug) do(x) diamonds[5, ]

Bad

if ( debug ) do(x) # No spaces around debug x[1,] # Needs a space after the comma x[1 ,] # Space goes after comma not before

### Curly braces

An opening curly brace should never go on its own line and should always be followed by a new line. A closing curly brace should always go on its own line, unless it's followed by `else`.

Always indent the code inside curly braces.

```{r, eval = FALSE}
# Good

if (y < 0 && debug) {
  message("Y is negative")
}

if (y == 0) {
  log(x)
} else {
  y ^ x
}

# Bad

if (y < 0 && debug)
message("Y is negative")

if (y == 0) {
  log(x)
} 
else {
  y ^ x
}

It's ok to leave very short statements on the same line:

```{r, eval = FALSE} if (y < 0 && debug) message("Y is negative")

### Line length

Strive to limit your code to 80 characters per line. This fits comfortably on a printed page with a reasonably sized font. If you find yourself running out of room, this is a good indication that you should encapsulate some of the work in a separate function.

### Indentation

When indenting your code, use two spaces. Never use tabs or mix tabs and spaces.

The only exception is if a function definition runs over multiple lines. In that case, indent the second line by four spaces:

```{r, eval = FALSE}
long_function_name <- function(a = "a long argument", 
    b = "another argument", c = "another long argument") {
  # As usual code is indented by two spaces.
}

Assignment

Use <-, not =, for assignment. \index{assignment}

# Good
x <- 5
# Bad
x = 5

Organisation

Commenting guidelines

Comment your code. Each line of a comment should begin with the comment symbol and a single space: #. Comments should explain the why, not the what. \index{comments}

Use commented lines of - and = to break up your file into easily readable chunks.

```{r, eval = FALSE}

Load data ---------------------------

Plot data ---------------------------

Use [roxygen2](https://github.com/cran/roxygen2) or [maxygen](https://github.com/gaborcsardi/maxygen) to document functions, if they will eventually find their way into a package.

```r
#' Add two numbers
#'
#' @param x first number
#' @param y second number
#' @return numeric equal to the sum of the two numbers.
#' @seealso \code{\link{nchar}} which this function wraps
#' @examples
#'   add(1, 2)
addTwoNumbers <- function(x, y){
  x + y
}

alteryx/jeeves documentation built on May 12, 2019, 1:40 a.m.