Partially implement nqp::shell() on parrot (ignores it's third argument).

Author: pmurias

src/vm/parrot/QAST/Operations.nqp

@@ -2379,6 +2379,7 @@ QAST::Operations.add_core_pirop_mapping('nfarunalt', 'nqp_nfa_run_alt', '0PsiPPP
 # process related opcodes
 QAST::Operations.add_core_pirop_mapping('exit', 'exit', '0i', :inlinable(1));
 QAST::Operations.add_core_pirop_mapping('sleep', 'sleep', '0n', :inlinable(1));
+QAST::Operations.add_core_pirop_mapping('shell', 'nqp_shell', 'IssP');
 QAST::Operations.add_core_op('getenvhash', -> $qastcomp, $op {
     if +@($op) != 0 {
         nqp::die('getenvhash requires no operands');

src/vm/parrot/ops/nqp.ops

@@ -3365,6 +3365,18 @@ inline op nqp_getlexrelcaller(out PMC, in PMC, in STR) :base_core {
     $1 = result;
 }
 
+inline op nqp_shell(out INT, in STR, in STR, in PMC) {
+     STRING *command = $2;  
+     STRING *dir = $3;  
+
+     PMC *env = $4;  
+     STRING * const old_cwd = Parrot_file_getcwd(interp);
+     Parrot_file_chdir(interp, dir);
+     $1 = Parrot_Run_OS_Command(interp, command);
+     Parrot_file_chdir(interp, old_cwd);
+}
+
+
 /*
 
 =item nqp_encode

t/nqp/78-shell.t

@@ -0,0 +1,5 @@
+plan(1);
+my $tmp_file := "tmp";
+nqp::shell("echo Hello > $tmp_file",nqp::cwd(),nqp::getenvhash());
+my $output := slurp($tmp_file);
+ok($output ~~ /^Hello/);