(PUP-1195) Fix is_numeric/is_integer when checking non-string parameters

I expect a function called "is_numeric" or "is_integer" to check if a
variable is an integer or a number even if the variable passed by isn't
a string nor a number at all. Otherwise we should call them
is_string_a_number and is_string_an_integer and we have then to remove
the check for .is_a?(Number) and .is_a?(FixNum)

now checking also if it is a hex or octal number

improved/corrected checking for integer

* checking against Integer instead of Fixnum so that
  also Bignum is matching
* now .is_a? Integer is done first so this is quiet fast

Now many types of numerics are recognized.

1. Float/Integer values (signed or unsigned, with exponent or without)
2. octal and hex check
3. except hex numbers and the "0." in a float lower than 1 can be prefixed
   with a '0'.

whitespaces shouldn't be allowed as prefix/suffix

string representation of numbers should not contain any type of
whitespace.. the user is responsible to clean a string before checking
it..

fix documentation and added more checks

tried to be 99.9% backward compatible

* for now the decission is post poned if hex and octal numbers
  should be allowed or not (is_numeric)
* native Bignum is now also a valid integer class

fix problem with old 1.8 ruby and Hash.to_s/Array.to_s

In ruby < 1.9 array and hashes would be recognized as numeric
if they have a special format:

1.8:

  [1,2,3,4].to_s = "1234"
  {1=>2}.to_s    = "12"

1.9:

  [1,2,3,4].to_s = "[1, 2, 3, 4]"
  {1=>2}.to_s    = "{1=>2}"

1 files changed, 21 insertions, 5 deletions

diff --git a/lib/puppet/parser/functions/is_integer.rb b/lib/puppet/parser/functions/is_integer.rb
index 6b29e98..3c4874e 100644
--- a/lib/puppet/parser/functions/is_integer.rb
+++ b/lib/puppet/parser/functions/is_integer.rb
@@ -4,7 +4,10 @@
 
 module Puppet::Parser::Functions
   newfunction(:is_integer, :type => :rvalue, :doc => <<-EOS
-Returns true if the variable returned to this string is an integer.
+Returns true if the variable passed to this function is an integer.
+
+If the variable is a string it has to be in the correct format of an
+integer.
     EOS
   ) do |arguments|
 
@@ -15,12 +18,25 @@ Returns true if the variable returned to this string is an integer.
 
     value = arguments[0]
 
-    if value != value.to_i.to_s and !value.is_a? Fixnum then
-      return false
-    else
+    # Regex is taken from the lexer of puppet
+    # puppet/pops/parser/lexer.rb but modified to match also
+    # negative values and disallow numbers prefixed with multiple
+    # 0's
+    #
+    # TODO these parameter should be a constant but I'm not sure
+    # if there is no risk to declare it inside of the module
+    # Puppet::Parser::Functions
+
+    # Integer numbers like
+    # -1234568981273
+    # 47291
+    numeric = %r{^-?(?:(?:[1-9]\d*)|0)$}
+
+    if value.is_a? Integer or (value.is_a? String and value.match numeric)
       return true
+    else
+      return false
     end
-
   end
 end