Equivalent of "source" in ruby?

ruby-talk
1

Contrary to my expectations, if I have some variable assignments in an
external file, I can't simply call:

    load rcfile

to have it sourced. Instead, I found myself having to do this:

    IO.foreach(rcfile) do |line|
  eval line
    end

which seems lame. Is there a better way?

···

--
"Oh, look: rocks!"
  -- Doctor Who, "Destiny of the Daleks"

2

Would globals work for you?

[alexg@powerbook]/Users/alexg/Desktop(28): cat load_me.rb
$global=10
local=20
[alexg@powerbook]/Users/alexg/Desktop(29): cat main.rb
load 'load_me.rb'

puts $global
puts local
[alexg@powerbook]/Users/alexg/Desktop(30): ruby main.rb
10
main.rb:4: undefined local variable or method `local' for main:Object (NameError)

Alex Gutteridge

Bioinformatics Center
Kyoto University

···

On 7 Sep 2007, at 14:17, Todd A. Jacobs wrote:

Contrary to my expectations, if I have some variable assignments in an
external file, I can't simply call:

    load rcfile

to have it sourced. Instead, I found myself having to do this:

    IO.foreach(rcfile) do |line|
  eval line
    end

which seems lame. Is there a better way?

3

#test1.rb:

        @a = 5
        @b = 4
        
        require 'test2'
        
        p @a
        p @b
        p @c

#----8<-----

#test2.rb:

        @b = 3
        @c = 2

$ ruby test1.rb
5
3
2
$

Or am I missing something?

···

On Fri, 2007-07-09 at 14:17 +0900, Todd A. Jacobs wrote:

Contrary to my expectations, if I have some variable assignments in an
external file, I can't simply call:

    load rcfile

to have it sourced. Instead, I found myself having to do this:

    IO.foreach(rcfile) do |line|
  eval line
    end

which seems lame. Is there a better way?

--
Michael T. Richter <ttmrichter@gmail.com> (GoogleTalk:
ttmrichter@gmail.com)
So much of what we call management consists in making it difficult for
people to work. (Peter Drucker)

4

Contrary to my expectations, if I have some variable
assignments in an external file, I can't simply call:

    load rcfile

Load starts a new scope without reusing the local scope. Eval
starts a new scope with reusing the local scope. So, use eval
instead. But you should "define" the vars before loading them.

gegroet,
Erik V. - http://www.erikveen.dds.nl/

···

----------------------------------------------------------------

$ cat test.rb
a=nil
b=nil

eval(File.read("vars.rb"))

# Or better: Thread.new{$SAFE=4 ; eval(File.read("vars.rb"),
Module.new.instance_eval{binding})}.join

p a
p b

----------------------------------------------------------------

$ cat vars.rb
a = 7
b = 8

----------------------------------------------------------------

$ ruby test.rb
7
8

----------------------------------------------------------------

5

It is also unsafe - not only because of the eval but also because this
will give errors for expressions that span multiple lines. The easy
fix would be

eval(File.read(rc_file))

But I'd rather resort to one of the other suggestions (namely using
local variables).

Kind regards

robert

···

2007/9/7, Todd A. Jacobs <tjacobs-sndr-019fdb@codegnome.org>:

Contrary to my expectations, if I have some variable assignments in an
external file, I can't simply call:

    load rcfile

to have it sourced. Instead, I found myself having to do this:

    IO.foreach(rcfile) do |line|
        eval line
    end

which seems lame. Is there a better way?

6

Yes, you are missing the local variable bit. :slight_smile:

robert

···

2007/9/7, Michael T. Richter <ttmrichter@gmail.com>:

On Fri, 2007-07-09 at 14:17 +0900, Todd A. Jacobs wrote:
Contrary to my expectations, if I have some variable assignments in an
external file, I can't simply call:

    load rcfile

to have it sourced. Instead, I found myself having to do this:

    IO.foreach(rcfile) do |line|
  eval line
    end

which seems lame. Is there a better way?

#test1.rb:

     @a = 5
     @b = 4

     require 'test2'

     p @a
     p @b
     p @c
  #----8<-----

#test2.rb:

     @b = 3
     @c = 2

$ ruby test1.rb
5
3
2
$

Or am I missing something?

7

a = nil
b = nil

Thread.new do
  data = File.read("vars.rb")
  $SAFE = 4
  b = Module.new.instance_eval{binding}

  eval(data, b)
end.join

p a
p b

8

That was intended to read "global" of course. Sorry for the noise.

robert

···

2007/9/7, Robert Klemme <shortcutter@googlemail.com>:

2007/9/7, Todd A. Jacobs <tjacobs-sndr-019fdb@codegnome.org>:
> Contrary to my expectations, if I have some variable assignments in an
> external file, I can't simply call:
>
> load rcfile
>
> to have it sourced. Instead, I found myself having to do this:
>
> IO.foreach(rcfile) do |line|
> eval line
> end
>
> which seems lame. Is there a better way?

It is also unsafe - not only because of the eval but also because this
will give errors for expressions that span multiple lines. The easy
fix would be

eval(File.read(rc_file))

But I'd rather resort to one of the other suggestions (namely using
local variables).

9

That would do it. :smiley:

···

On Fri, 2007-07-09 at 19:53 +0900, Robert Klemme wrote:

Yes, you are missing the local variable bit. :slight_smile:

--
Michael T. Richter <ttmrichter@gmail.com> (GoogleTalk:
ttmrichter@gmail.com)
When debugging, novices insert corrective code; experts remove defective
code. (Richard Pattis)

10

echo "Thread.critical = true; sleep" >> vars.rb

···

On Sep 7, 2007, at 03:55, Erik Veenstra wrote:

a = nil
b = nil

Thread.new do
  data = File.read("vars.rb")
  $SAFE = 4
  b = Module.new.instance_eval{binding}

  eval(data, b)
end.join

p a
p b

--
Poor workers blame their tools. Good workers build better tools. The
best workers get their tools to do the work for them. -- Syndicate Wars