I am working on an iPhone app. I am a full-time Java developer and I am used to using Eclipse where I can put a breakpoint in and stop the process. Then, I can type in any expression that I want and Eclipse will evaluate it using the values from that point in the process.
Is there a way to do that in Xcode? I want to be able to stop at a breakpoint and then enter some code to evaluate it. The gdb console will let me do po (print-object), but it is really limited. Any help?
In XCode 4.0 this is sort of hidden in the GUI. When you're at a breakpoint you can probably see the Variables View inside the Debug Area; it's the pane which shows local variables and such. Right-click on the Variables View and select "Add Expression..."
I realize this is an old thread but it's still a top Google hit so I thought it worth answering.
My practice:
po [NSUserDefaults standardUserDefaults]
displays: <NSUserDefaults: 0x6143040>
po [[NSUserDefaults standardUserDefaults] stringForKey:#"Currency"]
displays: "CHF"
Use the "expression" command in the debugger. Using it is relatively simple. Just type the command expression and press enter. You will then be prompted enter an expression. Here is an example
(lldb) expression
Enter expressions, then terminate with an empty line to evaluate:
2+2
(int) $2 = 4
I also attached the help info for the expression command below. Hope this helps.
Evaluate a C/ObjC/C++ expression in the current program context, using user
defined variables and variables currently in scope. This command takes
'raw' input (no need to quote stuff).
Syntax: expression --
Command Options Usage:
expression [-f ] [-G ] [-a ] [-d ] [-t ] [-u ] --
expression [-o] [-a ] [-d ] [-t ] [-u ] --
expression
-G <gdb-format> ( --gdb-format <gdb-format> )
Specify a format using a GDB format specifier string.
-a <boolean> ( --all-threads <boolean> )
Should we run all threads if the execution doesn't complete on one
thread.
-d <boolean> ( --dynamic-value <boolean> )
Upcast the value resulting from the expression to its dynamic type
if available.
-f <format> ( --format <format> )
Specify a format to be used for display.
-o ( --object-description )
Print the object description of the value resulting from the
expression.
-t <unsigned-integer> ( --timeout <unsigned-integer> )
Timeout value for running the expression.
-u <boolean> ( --unwind-on-error <boolean> )
Clean up program state if the expression causes a crash, breakpoint
hit or signal.
Timeouts:
If the expression can be evaluated statically (without runnning code) then it will be.
Otherwise, by default the expression will run on the current thread with a short timeout:
currently .25 seconds. If it doesn't return in that time, the evaluation will be interrupted
and resumed with all threads running. You can use the -a option to disable retrying on all
threads. You can use the -t option to set a shorter timeout.
User defined variables:
You can define your own variables for convenience or to be used in subsequent expressions.
You define them the same way you would define variables in C. If the first character of
your user defined variable is a $, then the variable's value will be available in future
expressions, otherwise it will just be available in the current expression.
Examples:
expr my_struct->a = my_array[3]
expr -f bin -- (index * 8) + 5
expr unsigned int $foo = 5
expr char c[] = "foo"; c[0]
IMPORTANT NOTE: Because this command takes 'raw' input, if you use any
command options you must use ' -- ' between the end of the command options
and the beginning of the raw input.
Not answering question about Xcode, but JetBrains' AppCode does this in the standard IDE way most of us know from other platforms.
Related
I'm trying to run a series of shell commands with Perl6 to the variable $cmd, which look like
databricks jobs run-now --job-id 35 --notebook-params '{"directory": "s3://bucket", "output": "s3://bucket/extension", "sampleID_to_canonical_id_map": "s3://somefile.csv"}'
Splitting the command by everything after notebook-params
my $cmd0 = 'databricks jobs run-now --job-id 35 --notebook-params ';
my $args = "'{\"directory\": \"$in-dir\", \"output\": \"$out-dir\",
\"sampleID_to_canonical_id_map\": \"$map\"}'"; my $run = run $cmd0,
$args, :err, :out;
Fails. No answer given either by Databricks or the shell. Stdout and stderr are empty.
Splitting the entire command by white space
my #cmd = $cmd.split(/\s+/);
my $run = run $cmd, :err, :out
Error: Got unexpected extra arguments ("s3://bucket", "output":
"s3://bucket/extension",
"sampleID_to_canonical_id_map":
"s3://somefile.csv"}'
Submitting the command as a string
my $cmd = "$cmd0\"$in-dir\", \"output\": \"$out-dir\", \"sampleID_to_canonical_id_map\": \"$map\"}'";
again, stdout and stderr are empty. Exit code 1.
this is something about how run can only accept arrays, and not strings (I'm curious why)
If I copy and paste the command that was given to Perl6's run, it works when given from the shell. It doesn't work when given through perl6. This isn't good, because I have to execute this command hundreds of times.
Perhaps Perl6's shell https://docs.perl6.org/routine/shell would be better? I didn't use that, because the manual suggests that run is safer. I want to capture both stdout and stderr inside a Proc class
EDIT: I've gotten this running with shell but have encountered other problems not related to what I originally posted. I'm not sure if this qualifies as being answered then. I just decided to use backticks with perl5. Yes, backticks are deprecated, but they get the job done.
I'm trying to run a series of shell commands
To run shell commands, call the shell routine. It passes the positional argument you provide it, coerced to a single string, to the shell of the system you're running the P6 program on.
For running commands without involving a shell, call the run routine. The first positional argument is coerced to a string and passed to the operating system as the filename of the program you want run. The remaining arguments are concatenated together with a space in between each argument to form a single string that is passed as a command line to the program being run.
my $cmd0 = 'databricks jobs run-now --job-id 35 --notebook-params ';
That's wrong for both shell and run:
shell only accepts one argument and $cmd0 is incomplete.
The first argument for run is a string interpreted by the OS as the filename of a program to be run and $cmd0 isn't a filename.
So in both cases you'll get either no result or nonsense results.
Your other two experiments are also invalid in their own ways as you discovered.
this is something about how run can only accept arrays, and not strings (I'm curious why)
run can accept a single argument. It would be passed to the OS as the name of the program to be run.
It can accept two arguments. The first would be the program name, the second the command line passed to the program.
It can accept three or more arguments. The first would be the program name, the rest would be concatenated to form the command line passed to the program. (There are cases where this is more convenient coding wise than the two argument form.)
run can also accept a single array. The first element would the program name and the rest the command line passed to it. (There are cases where this is more convenient.)
I just decided to use backticks with perl5. Yes, backticks are deprecated, but they get the job done.
Backticks are subject to code injection and shell interpolation attacks and errors. But yes, if they work, they work.
P6 has direct equivalents of most P5 features. This includes backticks. P6 has two variants:
The safer P6 alternative to backticks is qx. The qx quoting construct calls the shell but does not interpolate P6 variables so it has the same sort of level of danger as using shell with a single quoted string.
The qqx variant is the direct equivalent of P5 backticks or using shell with a double quoted string so it suffers from the same security dangers.
Two mistakes:
the simplistic split cuts up the last, single parameter into multiple arguments
you are passing $cmd to run, not #cmd
use strict;
my #cmd = ('/tmp/dummy.sh', '--param1', 'param2 with spaces');
my $run = run #cmd, :err, :out;
print(#cmd ~ "\n");
print("EXIT_CODE:\t" ~ $run.exitcode ~ "\n");
print("STDOUT:\t" ~ $run.out.slurp ~ "\n");
print("STDERR:\t" ~ $run.err.slurp ~ "\n");
output:
$ cat /tmp/dummy.sh
#!/bin/bash
echo "prog: '$0'"
echo "arg1: '$1'"
echo "arg2: '$2'"
exit 0
$ perl6 dummy.pl
/tmp/dummy.sh --param1 param2 with spaces
EXIT_CODE: 0
STDOUT: prog: '/tmp/dummy.sh'
arg1: '--param1'
arg2: 'param2 with spaces'
STDERR:
If you can avoid generating $cmd as single string, I would generate it into #cmd directly. Otherwise you'll have to implement complex split operation that handles quoting.
the code I have in my .zshrc is:
ytdcd () { #youtube-dl that automatically puts stuff in a specific folder and returns to the former working directory after.
cd ~/youtube/new/ && {
youtube-dl "$#"
cd - > /dev/null
}
}
ytd() { #sofar, this function can only take one page. so, i can only send one youttube video code per line. will modify it to accept multiple lines..
for i in $*;
do
params=" $params https://youtu.be/$i"
done
ytdcd -f 18 $params
}
so, on the commandline (terminal), when i enter ytd DFreHo3UCD0, i would like to have the video at https://youtu.be/DFreHo3UCD0 to be downloaded. the problem is that when I enter the command in succession, the system just tries to download the video for the previous command and rightly claims the download is complete.
For example, entering:
> ytd DFreHo3UCD0
> ytd L3my9luehfU
would not attempt to download the video for L3my9luehfU but only the video for DFreHo3UCD0 twice.
First -- there's no point to returning to the old directory for ytdcd: You can change to a new directory only inside a subshell, and then exec youtube-dl to replace that subshell with the application process:
This has fewer things to go wrong: Aborting the function's execution can't leave things in the wrong directory, because the parent shell (the one you're interactively using) never changed directories in the first place.
ytdcd () {
(cd ~/youtube/new/ && exec youtube-dl "$#")
}
Second -- use an array when building argument lists, not a string.
If you use set -x to log its execution, you'll see that your original command runs something like:
ytdcd -f 18 'https://youtu.be/one https://youtu.be/two https://youtu.be/three'
See those quotes? That's because $params is a string, passed as a single argument, not an array. (In bash -- or another shell following POSIX rules -- an unquoted string expansion would be string-split and glob-expanded, but zsh doesn't follow POSIX rules).
The following builds up an array of separate arguments and passes them individually:
ytd() {
local -a params=( )
local i
for i; do
params+=( "https://youtu.be/$i" )
done
ytdcd -f 18 "${params[#]}"
}
Finally, it's come up that you don't actually intend to pass all the URLs to just one youtube-dl instance. To run a separate instance per URL, use:
ytd() {
local i retval=0
for i; do
ytdcd -f 18 "$i" || retval=$?
done
return "$retval"
}
Note here that we're capturing non-success exit status, so as not to hide an error in any ytdcd instance other than the last (which would otherwise occur).
I would declare param as local, so that you are not appending url after urls...
You can try to add this awesome function to your .zshrc:
funfun() {
local _fun1="$_fun1 fun1!"
_fun2="$_fun2 fun2!"
echo "1 says: $_fun1"
echo "2 says: $_fun2"
}
To observe the thing ;)
EDIT (Explanation):
When sourcing shell script, you add it to you current environment, that is why you can run those function you define. So, when those function use variables, by default, those variable will be global and accessible from anywhere in your environment! Therefore, In this case param is defined globally for all the length of your shell session. Since you want to allow the download of several video at once, you are appending values to this global variable, which will grow all the time.
Enforcing local tells zsh to limit the scope of params to the function only.
Another solution is to reset the variable when you call the function.
Expect script query:
In one of my expect script I have to pick keyword from output of send command and store in a file, could some one help me.
send "me\n"
output :
EM/X Nmis Ssh Session/2; Userid =
Impact = ; Scope = ; CustomerId = 0
Here I want to pick keyword : Nmis Ssh Session/2
and my target is to create new command in expect script is :
send "set Nmis Ssh Session/2 \n"
so this value : Nmis Ssh Session/2 should store in a variable. Could some one help me.
I'm not quite sure exactly what information is produced by which side, but maybe something like this will do:
expect -re {EM/X ([^;]+);}
set theVariable $expect_out(1,string)
The key is that we use the -re option to pass a regular expression to the expect command. That makes the text that matches what is in the parentheses (a sequence of non-semicolon characters) be stored in the variable expect_out(1,string) (there are many other things stored in the expect_out array; see the documentation). Copying it from there to a named variable for the purpose of storage and further manipulation is trivial.
I do not know if the RE is the right one; there's something of an art in choosing the right one, and it takes quite a lot of knowledge about what the possible output of the other side could be.
I want to save the output of a program to a variable.
I use the following approach ,but fail.
$ PIPE RUN TEST | DEFINE/JOB VALUE #SYS$PIPE
$ x = f$logical("VALUE")
I got an error:%DCL-W-MAXPARM, too many parameters - reenter command with fewer parameters
\WORLD\
reference :
How to assign the output of a program to a variable in a DCL com script on VMS?
The usual way to do this is to write the output to a file and read from the file and put that into a DCL symbol (or logical). Although not obvious, you can do this with the PIPE command was well:
$ pipe r 2words
hello world
$ pipe r 2words |(read sys$pipe line ; line=""""+line+"""" ; def/job value &line )
$ sh log value
"VALUE" = "hello world" (LNM$JOB_85AB4440)
$
IF you are able to change the program, add some code to it to write the required values into symbols or logicals (see LIB$ routines)
If you can modify the program, using LIB$SET_SYMBOL in the program defines a DCL symbol (what you are calling a variable) for DCL. That's the cleanest way to do this. If it really needs to be a logical, then there are system calls that define logicals.
When I run ANY test I get the same message. Here is an example test:
package require tcltest
namespace import -force ::tcltest::*
test foo-1.1 {save 1 in variable name foo} {} {
set foo 1
} {1}
I get the following output:
WARNING: unknown option -run: should be one of -asidefromdir, -constraints, -debug, -errfile, -file, -limitconstraints, -load, -loadfile, -match, -notfile, -outfile, -preservecore, -relateddir, -singleproc, -skip, -testdir, -tmpdir, or -verbose
I've tried multiple tests and nothing seems to work. Does anyone know how to get this working?
Update #1:
The above error was my fault, it was due to it being run in my script. However if I run the following at a command line I got no output:
[root#server1 ~]$ tcl
tcl>package require tcltest
2.3.3
tcl>namespace import -force ::tcltest::*
tcl>test foo-1.1 {save 1 in variable name foo} {expr 1+1} {2}
tcl>echo [test foo-1.1 {save 1 in variable name foo} {expr 1+1} {2}]
tcl>
How do I get it to output pass or fail?
You don't get any output from the test command itself (as long as the test passes, as in the example: if it fails, the command prints a "contents of test case" / "actual result" / "expected result" summary; see also the remark on configuration below). The test statistics are saved internally: you can use the cleanupTests command to print the Total/Passed/Skipped/Failed numbers (that command also resets the counters and does some cleanup).
(When you run runAllTests, it runs test files in child processes, intercepting the output from each file's cleanupTests and adding them up to a grand total.)
The internal statistics collected during testing is available in AFACT undocumented namespace variables like ::tcltest::numTests. If you want to work with the statistics yourself, you can access them before calling cleanupTests, e.g.
parray ::tcltest::numTests
array set myTestData [array get ::tcltest::numTests]
set passed $::tcltest::numTests(Passed)
Look at the source for tcltest in your library to see what variables are available.
The amount of output from the test command is configurable, and you can get output even when the test passes if you add p / pass to the -verbose option. This option can also let you have less output on failure, etc.
You can also create a command called ::tcltest::ReportToMaster which, if it exists, will be called by cleanupTests with the pertinent data as arguments. Doing so seems to suppress both output of statistics and at least most resetting and cleanup. (I didn't go very far in investigating that method.) Be aware that messing about with this is more likely to create trouble than solve problems, but if you are writing your own testing software based on tcltest you might still want to look at it.
Oh, and please use the newer syntax for the test command. It's more verbose, but you'll thank yourself later on if you get started with it.
Obligatory-but-fairly-useless (in this case) documentation link: tcltest