Protected program in a program

ruby-talk
1

Hello,

I’ve got a kind of tricky question. For my tutorial there are lots of code
samples, and I usually want to display the output of them in the page. I’d
like to automate this. I’m generating all of the pages in mod_ruby.

Because there are so many of them, though, I’d like them to be safe from
each other… I guess each one should be in it’s own namespace? (I don’t
know much about namespaces… better not cover that in the tutorial!)

I’m hoping for something like this:

code = "puts ‘hello’"
output = executeCode (code)
output # should be “hello\n”

Each code sample is supposed to be it’s own program, so I don’t want any
possibilities of variables showing up in code samples further on down the
page, and certainly not on subsequent calls to that page! Does any one
know how I could do this?

OK, if you can handle that, how about this…

Many of the programs require input. Is there a way I could queue up the
input I want to send the program before it is run? Something like this:

code = <<-'END_CODE
str1 = gets
str2 = gets
puts str1
puts str2
END_CODE

input = “hello\n”+
“hi\n”

Then I’ll strip the leading whitespace out of the code.

output = executeCode (code, input)

If you can do that, you have helped me greatly. However, the perfect
solution would be a little bit trickier…

I would like to echo the input back into the output in the right place (just
like would happen when running such a program from the commandline), and
surround it in special tags so I can change it’s style from the
’output’ style to the ‘input’ style.

Do I have a hero out there?

Chris

EXTRA CREDIT: Point me to some regexps for Ruby syntax coloring! I’m sure
I don’t need to reinvent that wheel.

2

Hello,

I’ve got a kind of tricky question. For my tutorial there are lots of code
samples, and I usually want to display the output of them in the page. I’d
like to automate this. I’m generating all of the pages in mod_ruby.

Because there are so many of them, though, I’d like them to be safe from
each other… I guess each one should be in it’s own namespace? (I don’t
know much about namespaces… better not cover that in the tutorial!)

I’m hoping for something like this:

code = “puts ‘hello’”
output = executeCode (code)
output # should be “hello\n”

Each code sample is supposed to be it’s own program, so I don’t want any
possibilities of variables showing up in code samples further on down the
page, and certainly not on subsequent calls to that page! Does any one
know how I could do this?

Well, you could just call ruby in a sub-shell. The easiest way would be to
use the backtick operators. The naive implementation might use ruby -e, but
you might want to write the code to some sort of tmp file and then execute
that file.

def executeCode(code)
ecode = code.gsub(‘"’, ‘"’)
return ruby -e "#{ecode}"
end

code = %Q(puts “Hello”)

output = executeCode(code)

puts code
puts “\nReturned:\n#{output}”

OK, if you can handle that, how about this…

Many of the programs require input. Is there a way I could queue up the
input I want to send the program before it is run? Something like this:

code = <<-'END_CODE
str1 = gets
str2 = gets
puts str1
puts str2
END_CODE

input = “hello\n”+
“hi\n”

Then I’ll strip the leading whitespace out of the code.

output = executeCode (code, input)

If you went writing the code as well as the input to temporary files,
the backtick command in executeCode above might go to
ruby tmpcode.rb < tmpinput.rb

If you can do that, you have helped me greatly. However, the perfect
solution would be a little bit trickier…

I would like to echo the input back into the output in the right place (just
like would happen when running such a program from the commandline), and
surround it in special tags so I can change it’s style from the
‘output’ style to the ‘input’ style.

Now that, I’ll have to think about…

···

On Sat, Dec 07, 2002 at 02:54:17AM +0900, Chris Pine wrote:

–
Alan Chen
Digikata Computing
http://digikata.com