eval

I am trying to run a chunk of R code in a sandbox-ed fashion, by loading all the necessary dependencies (functions and data) into a new environment and evaluating an expression within that environment. However, I'm running into trouble with functions calling other functions in the environment. Here's a simple example: jobenv <- new.env(parent=globalenv()) assign("f1", function(x) x*2, envir=jobenv) assign("f2", function(y) f1(y) + 1, envir=jobenv) expr <- quote(f2(3)) Using eval on expr fails since f2 can't find f1 > eval(expr, envir=jobenv) Error in f2(3) : could not find function "f1"

I'm guessing this should be something obvious to those knowing Perl, but I simply don't get it.. I also guess it has to do with problems described in Perl scoping « darkness - but I cannot apply any of that in my case. Anyways, here's the code: #!/usr/bin/env perl # call with: # ./test.pl use strict; my $tvars = "my \$varA = 1; my \$varB = 2; my \$varC = 3; "; my @lines = split /\n/, $tvars; foreach my $line (@lines) { print "$line\n"; eval $line; warn $@ if $@; } #~ print "$varA\n"; # Global symbol "$varA" requires explicit package name at ./test.pl line 18. #~ print "$varB\n"; # Global

In PHP, I want to read a file into a variable and process the PHP in the file at the same time without using output buffering. Is this possible? Essentially I want to be able to accomplish this without using ob_start() : <?php ob_start(); include 'myfile.php'; $xhtml = ob_get_clean(); ?> Is this possible in PHP? Update: I want to do some more complex things within an output callback (where output buffering is not allowed). A little known feature of PHP is being able to treat an included/required file like a function call, with a return value. For example: // myinclude.php $value = 'foo';

I'm having difficulty nested quotes within a bash script argv="su -c '$RVM_PATH wrapper $config_rvm \'$PASSENGER_RVM_BIN $command $options\'' web" eval $argv The above got me eval: line 162: unexpected EOF while looking for matching `'' eval: line 163: syntax error: unexpected end of file argv="su -c \"$RVM_PATH wrapper $config_rvm \\\"$PASSENGER_RVM_BIN $command $options\\\"\" web" That's because \' doesn't have any special meaning within a single-quoted string; it means simply "backslash, followed by end-of-string". One option is to use $'...' instead of '... '; that will let you use

Is there any way I can convert a string of code into executable code at runtime in c#? So if I have a file of predicates This is normal text in a txt file u => u.Contains("android") && u.Contains("webkit") u => u.Contains("iphone") && u.Contains("webkit") I would want to read it in via my program and then capture each predicate as a string and then convert it to code on the fly. Something like: string[] predicates = ///get file contentsa foreach(var predicate in predicates) { if(userAgent.ConformsTo(eval(predicate))) return true; } You can use CSharpCodeProvider class, but you'll need to build