Ruby Methods and Splat

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Ruby methods can set default values for optional arguments:

def commit(path=Dir.pwd)

To take an optional number of arguments a splat can be used:

def amethod( *arg1 )

The Problem is now to set defaults or require a set number of arguments.

  1. Splat arguments can not be defaulted.
  2. The splat can accept zero arguments.

The following might be what you would expect for a default in a splat, but this conflicts with its abilliy to accept 0 arguments.

def commit(*path=[Dir.pwd]) ##THIS DOES NOT WORK

Splats can follow other arguments. To require at least one argument:

def add(files, *files_splat)

No arguments required but the first has a default:

def commit(path=Dir.pwd, *path_splat)

These also work as expected in Thor for parsing command line options. I have used them in my dssx gem.

In thor I also add this to the start of my methods to combine path and path_splat which are strings:

path_list = path + ' ' + path_splat * ' '