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Coding Style

Creation Date: Antiquity. Last Edit Date: 13 Aug 2015.

Using similar coding style helps people understand code. These guidelines are preferences and strongly encouraged.

Indentation

  • Use 4 spaces for indenting. No tabs.
  • No lines longer than 80 characters.

Variable names

  • Use camelCaps: initial lowercase, then alternate case between words.

Function names

  • Use camelCaps: initial lower case, then alternate case between words.
  • Do not use ‘.’ (in the S3 class system, some(x) where x is class A will dispatch to some.A).
  • Prefix non-exported functions with a ‘.’.

Class names

  • Use CamelCaps: initial upper case, then alternate case between words.

File names

  • Filename extension for R code should be ‘.R’. Use the prefix ‘methods-‘ for S4 class methods, e.g., ‘methods-coverage.R’. Generic definitions can be listed in a single file, ‘AllGenerics.R’, and class definitions in ‘AllClasses.R’.
  • Filename extension for man pages should be ‘.Rd’.

Use of space

  • Always use space after a comma. This: a, b, c.
  • No space around “=” when using named arguments to functions. This: somefunc(a=1, b=2)
  • Space around all binary operators: a == b.

Comments

  • Use “##” to start full-line comments.
  • Indent at the same level as surrounding code.

Namespaces

  • Import all symbols used from packages other than “base”. Except for default packages (base, graphics, stats, etc.) or when overly tedious, fully enumerate imports.
  • Export all symbols useful to end users. Fully enumerate exports.

End-User messages

  • message() communicates diagnostic messages (e.g., progress during lengthy computations) during code evaluation.
  • warning() communicates unusual situations handled by your code.
  • stop() indicates an error condition.
  • cat() or print() are used only when displaying an object to the user, e.g., in a show method.

Misc

  • Use <- not = for assignment.