If you run a script in Rebol and say something like print {Hello}, you end up calling the system version of PRINT
>> bind? 'print
== make object! [
system: make object! [
product: 'core
version: 2.101.0.2.5
build: 22-Jan-2013/2:44:29
platform: [
Macintosh osx-x86
]
license: {Copyright 2012 REB....
Let's say I had a script %repl-context.r and it defined a context where PRINT did something else. Is there a way to ask the REPL to interactively run within that context, for several consecutive commands...?
There is a common repl console wrapper around to handle I/o redirects for StdIn StdOut.
I often use rlwrap from http://utopia.knoware.nl/~hlub/rlwrap/#rlwrap
It uses GNU readline lib
I'm not exactly certain of the purpose, but you could subvert the console with your own input/output process with a managed loop:
while [not find ["q" "quit"] command: ask "my-prompt> "][
result: do bind load command 'my-context
if value? result [print ["==" mold result]]
()
]
I use this method with my HTTP Console for R2.
Another possibility is digging into the workings of the system/ports/input port.
Related
As part of a little project, I'm writing a shell in Ada. As such, when I was investigating the system calls, I learned that there are three ways to do it.
The POSIX system calls, which are probably the least reliable.
Passing the arguments along to C's system(), which I didn't really want to do, since this was about writing the emulator in Ada and not C.
Using GNAT's runtime libraries.
I chose to go for the last option, considering this to be the most "Ada-like" of the choices. I found a code snippet on RosettaCode here. I copied and pasted it and compiled it after changing the "cmd.exe" to "ls" and removing the second argument definition. However, nothing happens when I run the executable. The shell just goes right back to the prompt. I have tested this on two different computers, one running Fedora 21, the other Debian Jessie. Here's what I've done to test it:
Seen if lacking an arguments string caused it
Checked if any of the file descriptors in GNAT's libraries are mis-named
Redirected both stderr and stdin to stdout just to see if GNAT was dumping them to the wrong FD anyway.
Looked thoroughly through the System.OS_lib library file, and there seems to be no reason.
Googled it, but GNAT's own page on the GCC website is very poorly documented.
For now I'm using the C.Interface system in the preparation of my shell, but I'm dissatisfied with this. I'm new to Ada and have only been tinkering with it for a month or so now, so if there's some kind of Ada wisdom here that would help I'm not in on it.
UPDATE: I have tried running it with absolute path, both to /usr/bin and /bin locations, and it doesn't work. Interestingly, the result code returned by the operating system is 1, but I don't know what that means. A quick search suggests that it's for "all general errors", and another site suggests that it's for "incorrect functions".
I had to tweak the RosettaCode example a little to run /bin/ls on Debian Linux, but it does run as expected...
with Ada.Text_IO; use Ada.Text_IO;
with Gnat.OS_Lib; use Gnat.OS_Lib;
procedure Execute_Synchronously is
Result : Integer;
Arguments : Argument_List :=
( 1=> new String'("-al")
);
begin
Spawn
( Program_Name => "/bin/ls",
Args => Arguments,
Output_File_Descriptor => Standout,
Return_Code => Result
);
for Index in Arguments'Range loop
Free (Arguments (Index));
end loop;
end Execute_Synchronously;
Changes :
my Gnat (FSF Gnat 4.92 from Debian Jessie) warned about System.OS_Lib, recommending Gnat.OS_Lib instead. (Which simply renames System.OS_Lib .... why???
System.OS_Lib comments:
-- Note: this package is in the System hierarchy so that it can be directly
-- be used by other predefined packages. User access to this package is via
-- a renaming of this package in GNAT.OS_Lib (file g-os_lib.ads).
Program name including path.
Arguments. The first time I ran it, it displayed the details of "ls" itself, because it was given its own name as the first argument, so I deleted that to see the current directory instead.
Notes :
the best information ot the available subprograms and their arguments is usually in the package specs themselves in the "adainclude" folder : this is /usr/lib/gcc/x86_64-linux-gnu/4.9/adainclude on my Debian installation, locate system.ads will find yours. The specific files are: s-os_lib.ads for System.OS_Lib which exports Spawn and Standout, and a-textio.ads for Ada.Text_IO.
Standout is not the preferred way of accessing Standard Output : it's a file descriptor (integer), the preferred way would be the Standard_Output function from Ada.Text_IO which returns a File. However there doesn't seem to be an overload for Spawn which takes a File (nor would I expect one in this low level library) so the lower level file descriptor is used here.
Absent a shell, you'll need to search the PATH yourself or specify a full path for the desired executable:
Spawn (
Program_Name => "/bin/ls",
…
);
I have tried running it with absolute path…neither /usr/bin nor /bin locations work.
Use which to determine the full path to the executable:
$ which ls
/bin/ls
I have been trying to run a shell script at boot time of freebsd. I have read all simmilar questions in stackoverflow and tried. But nothing is worked. This is the sample code that i tried is dummy.
#!/bin/sh
. /etc/rc.subr
name="dummy"
start_cmd="${name}_start"
stop_cmd=":"
dummy_start()
{
echo "Nothing started."
}
load_rc_config $name
run_rc_command "$1"
Saved with name of dummy.
Permissions are -r-xr-xr-x.
in rc.conf file made dummy_enable="YES".
The problem is, when i rebooted my system to test, dummy file is not there. So script is not executing. what else need to do run my dummy script.
SRC:http://www.freebsd.org/doc/en/articles/rc-scripting/article.html#rc-flags
You need to add rcvar="dummy_enable" to your script. At least for FreeBSD 9.1.
Call your script with parameter rcvar to get the enabled status:
# /etc/rc.d/dummy rcvar
# dummy
#
dummy_enable="YES"
# (default: "")
And finally start it with parameter start - this won't start the service/script unless dummy_enable is set in /etc/rc.conf (or /etc/rc.conf.local, or /etc/defaults/rc.conf)
# /etc/rc.d/dummy start
Nothing started.
One possible explanation is that rcorder(8) says:
Within each file, a block containing a series of "REQUIRE", "PROVIDE",
"BEFORE" and "KEYWORD" lines must appear.
Though elsewhere I recall that if a file doesn't have "REQUIRE", "PROVIDE" or "BEFORE", then it will be arbitrarily placed in the dependency ordering. And, it could be that the arbitrary placement differs between the first run up to $early_late_divider and in the second run of those after $early_late_divider.
OTOH, is this a stock FreeBSD, or some variant? I recall reading that FreeNAS saves its configuration somewhere else and recreates its system files on every boot. And, quite possibly that /etc is actually on a ramdisk.
Also, /usr/local/etc/rc.d doesn't come into existence until the first port installing an rc file is installed.
This example routine generates two Throw::nocatch warning messages in the kernel window. Can they be handled somehow?
The example consists of this code in a file "test.m" created in C:\Temp:
Needs["JLink`"];
$FrontEndLaunchCommand = "Mathematica.exe";
UseFrontEnd[NotebookWrite[CreateDocument[], "Testing"]];
Then these commands pasted and run at the Windows Command Prompt:
PATH = C:\Program Files\Wolfram Research\Mathematica\8.0\;%PATH%
start MathKernel -noprompt -initfile "C:\Temp\test.m"
Addendum
The reason for using UseFrontEnd as opposed to UsingFrontEnd is that an interactive front end may be required to preserve output and messages from notebooks that are usually run interactively. For example, with C:\Temp\test.m modified like so:
Needs["JLink`"];
$FrontEndLaunchCommand="Mathematica.exe";
UseFrontEnd[
nb = NotebookOpen["C:\\Temp\\run.nb"];
SelectionMove[nb, Next, Cell];
SelectionEvaluate[nb];
];
Pause[10];
CloseFrontEnd[];
and a notebook C:\Temp\run.nb created with a single cell containing:
x1 = 0; While[x1 < 1000000,
If[Mod[x1, 100000] == 0,
Print["x1=" <> ToString[x1]]]; x1++];
NotebookSave[EvaluationNotebook[]];
NotebookClose[EvaluationNotebook[]];
this code, launched from a Windows Command Prompt, will run interactively and save its output. This is not possible to achieve using UsingFrontEnd or MathKernel -script "C:\Temp\test.m".
During the initialization, the kernel code is in a mode which prevents aborts.
Throw/Catch are implemented with Abort, therefore they do not work during initialization.
A simple example that shows the problem is to put this in your test.m file:
Catch[Throw[test]];
Similarly, functions like TimeConstrained, MemoryConstrained, Break, the Trace family, Abort and those that depend upon it (like certain data paclets) will have problems like this during initialization.
A possible solution to your problem might be to consider the -script option:
math.exe -script test.m
Also, note that in version 8 there is a documented function called UsingFrontEnd, which does what UseFrontEnd did, but is auto-configured, so this:
Needs["JLink`"];
UsingFrontEnd[NotebookWrite[CreateDocument[], "Testing"]];
should be all you need in your test.m file.
See also: Mathematica Scripts
Addendum
One possible solution to use the -script and UsingFrontEnd is to use the 'run.m script
included below. This does require setting up a 'Test' kernel in the kernel configuration options (basically a clone of the 'Local' kernel settings).
The script includes two utility functions, NotebookEvaluatingQ and NotebookPauseForEvaluation, which help the script to wait for the client notebook to finish evaluating before saving it. The upside of this approach is that all the evaluation control code is in the 'run.m' script, so the client notebook does not need to have a NotebookSave[EvaluationNotebook[]] statement at the end.
NotebookPauseForEvaluation[nb_] := Module[{},While[NotebookEvaluatingQ[nb],Pause[.25]]]
NotebookEvaluatingQ[nb_]:=Module[{},
SelectionMove[nb,All,Notebook];
Or##Map["Evaluating"/.#&,Developer`CellInformation[nb]]
]
UsingFrontEnd[
nb = NotebookOpen["c:\\users\\arnoudb\\run.nb"];
SetOptions[nb,Evaluator->"Test"];
SelectionMove[nb,All,Notebook];
SelectionEvaluate[nb];
NotebookPauseForEvaluation[nb];
NotebookSave[nb];
]
I hope this is useful in some way to you. It could use a few more improvements like resetting the notebook's kernel to its original and closing the notebook after saving it,
but this code should work for this particular purpose.
On a side note, I tried one other approach, using this:
UsingFrontEnd[ NotebookEvaluate[ "c:\\users\\arnoudb\\run.nb", InsertResults->True ] ]
But this is kicking the kernel terminal session into a dialog mode, which seems like a bug
to me (I'll check into this and get this reported if this is a valid issue).
Can I replace an executable (accessed via a system call from ruby) with an executable that expects certain input and supplies the expected output in a consistent amount of time? I'm mainly operating on Mac OSX 10.6 (Snow Leopard), but I also have access to Linux and Windows. I'm using MRI ruby 1.8.7.
Background: I'm looking at doing several DNA sequence alignments, one in each thread. When I try using BioRuby for this, either BioRuby or ruby's standard library's tempfile sometimes raise exceptions (which is better than failing silently!).
I set up a test that reproduces the problem, but only some of the time. I assume the main sources of variability between tests are the threading, the tempfile system, and the executable used for alignment (ClustalW). Since ClustalW probably isn't malfunctioning, but can be a source of variability, I'm thinking that eliminating it may aid reproducibility.
For those thinking select isn't broken - that's what I'm wondering too. However, according to the changelog, there was concern about tempfile's thread safety in August 2009. Also, I've checked on the BioRuby mailing list whether I'm calling the BioRuby code correctly, and that seems to be the case.
I really don't understand what the problem is or what exactly are you after, can't you just write something like
#!/bin/sh
#Test for input (syntax might be wrong, but you get the idea)
if [ $* ne "expected input" ]; then
echo "expected output for failure"
exit -1
fi
#have it work in a consistent amount of time
$CONSISTENT_AMOUNT_OF_TIME = 20
sleep $CONSISTENT_AMOUNT_OF_TIME
echo "expected output"
You can. In cases where I'm writing a functional test for program A, I may need to "mock" a program, B, that A runs via system. What I do then is to make program B's pathname configurable, with a default:
class ProgramA
def initialize(argv)
#args = ParseArgs(argv)
#config = Config.new(#args.config_path || default_config_path)
end
def run
command = [
program_b_path,
'--verbose',
'--do_something_wonderful',
].join(' ')
system(command)
...
end
def program_a_path
#config.fetch('program_b_path', default_program_b_path)
end
end
Program A takes a switch, "--config PATH", which can override the default config file path. The test sets up a configuration file in /tmp:
program_b_path: /home/wayne/project/tests/mock_program_b.rb
And passes to program A that configuration file:
program_a.rb --config /tmp/config.yaml
Now program A will run not the real program B, but the mock one.
Have you tried the Mocha gem? It's used a lot for testing, and you describe it perfectly. It "fakes" the method call of an object (which includes just about anything in ruby), and returns the result you want without actually running the method. Take this example file:
# test.rb
require 'rubygems'
require 'mocha'
self.stubs(:system).with('ls').returns('monkey')
puts system('ls')
Running this script outputs "monkey" because I stubbed out the system call. You can use this to bypass parts of an application you don't want test, to factor out irrelevant parts.
I want to build an application with a text based UI that is similar to the Linux command 'top', in Ruby. What toolkits and/or techniques can I use to build the UI? In particular I want an area of the console window that is constantly updating, and the ability to press keys to manipulate the display.
For a terminal interface, see http://ncurses-ruby.berlios.de/
Ncurses is great for console apps and you can find bindings for it for lots of languages (or just use shell scripting). There's even a cursed gtk (http://zemljanka.sourceforge.net/cursed/) though I think work on it stopped quite awhile back.
You didn't mention your platform, but for OS/X there's a great little app called Geektool (http://projects.tynsoe.org/en/geektool/) which allows you to put script output on your desktop. I use a small ruby script to generate my top processes list:
puts %x{uptime}
IO.popen("ps aruxl") { |readme|
pslist = readme.to_a
pslist.shift # remove header line
pslist.each_with_index { |i,index|
ps = i.split
psh = { user: ps[0], pid: ps[1], pcpu: ps[2], pmem: ps[3],
vsz: ps[4], rss: ps[5], tty: ps[6], stat: ps[7],
time: ps[8], uid: ps[9], ppid: ps[10], cpu: ps[11], pri: ps[12],
nice: ps[13], wchan: ps[14], cmd: ps[16..ps.size].join(" ") }
printf("%-6s %-6s %-6s %s", "PID:", "%CPU:", "%Mem", "Command\n") if index == 0
printf("%-6d %-6.1f %-6.1f %s\n",
psh[:pid].to_i, psh[:pcpu].to_f, psh[:pmem].to_f, psh[:cmd]) if index < 10
}
}
(This could probably be better, but it was the first ruby script I ever wrote and since it works I've never revisited it to improve it - and it doesn't take input. Anyway, it might help give you some ideas)
there's stfl but i don't know if the ruby bindings are maintained. ncurses is probably your best bet.