From 00c881d0dabe77fd2401beb0d39c7386b50bb791 Mon Sep 17 00:00:00 2001 From: David Schmitt Date: Mon, 14 Sep 2015 18:26:25 +0100 Subject: (MODULES-2516) Adds an is_a() function The data type system is very hard to understand. Many people don't understand why type_of([1,2,3]) == Array will fail, but type_of([1,2,3]) <= Array passes. This does a simpler validation that doesn't rely on explicit data types. Instead, use $foo = [1,2,3] if $foo.is_a(Array) { notify { 'This is an array': } } This is based on code by Ben Ford . * Added acceptance tests * Added dispatch * Improved unit tests * Added docs to README --- lib/puppet/functions/is_a.rb | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 lib/puppet/functions/is_a.rb (limited to 'lib/puppet/functions') diff --git a/lib/puppet/functions/is_a.rb b/lib/puppet/functions/is_a.rb new file mode 100644 index 0000000..da98b03 --- /dev/null +++ b/lib/puppet/functions/is_a.rb @@ -0,0 +1,32 @@ +# Boolean check to determine whether a variable is of a given data type. This is equivalent to the `=~` type checks. +# +# @example how to check a data type +# # check a data type +# foo = 3 +# $bar = [1,2,3] +# $baz = 'A string!' +# +# if $foo.is_a(Integer) { +# notify { 'foo!': } +# } +# if $bar.is_a(Array) { +# notify { 'bar!': } +# } +# if $baz.is_a(String) { +# notify { 'baz!': } +# } +# +# See the documentation for "The Puppet Type System" for more information about types. +# See the `assert_type()` function for flexible ways to assert the type of a value. +# +Puppet::Functions.create_function(:is_a) do + dispatch :is_a do + param 'Any', :value + param 'Type', :type + end + + def is_a(value, type) + # See puppet's lib/puppet/pops/evaluator/evaluator_impl.rb eval_MatchExpression + Puppet::Pops::Types::TypeCalculator.instance?(type, value) + end +end -- cgit v1.2.3