reflection and hooks

Perl Ruby PHP Python

スクリプト言語の比較

http://hyperpolyglot.org/scripting を参考に、スクリプト言語の勉強をしてまいります。

reflection and hooks









































  perl php python ruby
class 

ref $a


<?php
get_class($a)
?>


type(a)


a.class

has method? 

$a->can('reverse')


<?php
method_exists($a, 'reverse')
?>


hasattr(a,'reverse')


a.respond_to?('reverse')

message passing 

for $i (0..10) {
  $meth = "phone$i";
  $a->$meth(undef);
}


<?php
for ($i = 1; $i <= 10; $i++) {
  call_user_func(array($a,
    "phone$i"), NULL);
}
?>


for i in range(1,10):
  getattr(a,"phone"+str(i))(None)


(1..9).each do |i|
  a.send("phone#{i}="nil)
}

eval 

while(<>) {
  print ((eval), "\n");
}


<?php
?>


while True:
  print(eval(sys.stdin.readline()))


loop do
  puts eval(gets)
end

methods 

$class = ref($a);
keys eval "%${class}::";


<?php
?>


[m for m in dir(a) if callable(getattr(a,m))]


a.methods

attributes 

keys %$a;


<?php
?>


dir(a)


a.instance_variables

pretty print 

require 'dumpvar.pl';
%h = ('foo'=>1, 'bar'=>[2, 3]);
dumpValue(\%h);


<?php
$h = array('foo'=>1, 'bar'=>array(2,3));
print_r($h);
?>


import pprint
h = {'foo':1, 'bar':[2,3] }
pprint.PrettyPrinter().pprint(h)


require 'pp'
h = { 'foo'=>1, 'bar'=>[2,3] }
pp h

source line number and file name 

__LINE__
__FILE__


<?php
__LINE__
__FILE__
?>


import inspect
c = inspect.currentframe()
c.f_lineno
c.f_code.co_filename


__LINE__
__FILE__

スクリプト言語の比較 - 目次

main page
arithmetic and logic
strings
containers
functions
execution control
environment and i/o
libraries and modules
objects
reflection and hooks