MATLAB has a feature to allow users to introduce a command in the script/function called keyboard and have the code stop there with a console/command prompt that gives direct access to the interpreter and the variable space. MATLAB keyboard() command docs
Is there something similar in Powershell? I don't want to deal with Powershell ISE as I don't like it's syntax highlighting (doesn't highlight all occurrences of selected phrase like Notepad++ does) and the macros is a lot weaker than what the plain Powershell console itself (like lacking F8 for recalling).
Stepping with a debugger is not quite as useful when you need to explore complex object structures and try a few things out with the current variable states, instead of just reading what the variables and values are in a docked window. It's much easier to work with the state of mind of the interpreted language at any point by interacting with it instead of ploughing through stack and trace information.
In both Powershell ISE and VSCode, you can read or update the same variables in your session from the terminal window at the bottom, even during debugging.
Related
I have an executable created with mcc. The .m file has a simple function that reads and plots values. After I run it from DOS, it freeze without returning execution to DOS. 2 questions:
1) How can i return execution to dos? I tried "return" and "exit" commands but didnt help
2) How to close the dos windows? is the only way to use a batch file or can I do it with a command in the .m file?
thanks
A.
There are 2 scenarii:
If your run your matlab executable from a DOS window, the DOS window will not get control back until the program terminates. If the program generate matlab figures (plot, surf, etc...), the program will not return to the console until all of the figures are closed.
You may think it is a waste for a simple plot, but after all your figure could be a evolved gui with a lot of code to execute. Or even a simple figure with a closeRequestFcn. So in Matlab terms, your program may still have instructions to execute as long as a figure is opened, so it will not return until it sure there is nothing more to do.
If you simply double clicked on your executable, the DOS looking console which open with your program will have the same behaviour. It will not disappear until the program returns (so until all your figures are closed if relevant).
I am not sure about linux, versions, but if you are running on windows, there is a way to suppress the DOS looking console for your graphic applications. Look at the -e switch in the mcc options.
This switch will compile your program in a way that no DOS console is opened when you double click on your executable.
So to summarize, I would recommend:
If your program is a 'command line' type (a function that takes input from the console and return values to the same). => Compile with normal options, and execute it from a DOS window (you do not want the window to disapear as soon as the program terminates.)
If your program is a gui or even simple plotting functions, with no need for console interactions, then compile with the -e switch and execute it by double clicking the .exe file.
note that in case you use the -e switch, it is recommended to direct potential output to a logfile. Look at the mcc documentation for more info.
edit
If you really need the DOS console and some graphic output, run your program form the command window with the following syntax:
start /b YourProgram
This will start the program in "background mode" (use YourProgram & in Linux terminal). You will be able to do anything in this console window, and you will also see the output from your matlab executable.
It can be confusing because the output from your program will be added to the simple dos prompt and you may think you do not have the control but if you type any command it will work. You can even start many program this way and retain control in your console, but all the output will arrive in the same window and they may be difficult to differentiate.
This is weird.
I know tab is for command completion in the PowerShell ISE and fine so. But, it also messes up the editing pane.
Do this:
File > New (Untitled1.ps1 opens)
Press tab (all fine, you get an indent)
type enter, # (comment) and press tab after it
expected: one would get indentation after the hash
actual: one gets the hash replaced by $PSVersionTable or whatever the command prompt has in its history! (tab and Shift-tab circle through those)
Does this mean no-one uses tabs within comments in PowerShell scripts, or that no-one uses comments in PowerShell scripts?
Can I turn off this behavior anywhere?
Also, the behavior seems to be inconsistent. If I e.g. type ##, sometimes tab does not do the completion (it does not enter a tab either).
Can others reproduce this?
System:
Windows 8.1 Pro
PowerShell ISE
To answer the main question, you can enter Alt+09 (using numeric keypad) to enter <Tab>.
For the behavior described, I see this as expected behavior. You can get history completion by typing # and part of a previous command then pressing Tab repeatedly will cycle backwards through matching history. Typing # alone will match all history starting with the last command.
Does this mean no-one uses tabs within comments in PowerShell scripts?
Anecdotal, but I've never used tabs in a single line comment, but I do often use tabs within multiline comments which are bracketed by <# and #>. E.g.
<#
Functions
Get-Foo
Get-Bar
Variables
$Foo
$Bar
#>
Function Get-Foo { ...
With multiline comments, the auto-completion will not be an issue.
, or that no-one uses comments in PowerShell scripts?
I don't know why this would be implied by the behavior; I always use a single space to start a line comment.
I find this helpful when developing a script as I often try expressions in the command pane if I'm unsure of the behavior, then add the expression to the script if it works.
So, my workflow would be:
Ctrl-D to go to the Command Pane
Type a command
If the command did what I wanted, Ctrl-I to go to the Script Pane
Type #<Tab>, and the line is added to the script.
I have recently started using MATLAB without GUI by starting matlab with -nodesktop option and it is considerably faster.
However presently I have no way to debug a .m script in non gui mode. I have to open the default matlab editor every time I have to debug.Has anyone figured out a way to do it?
Thanks in advance
I am using Ubuntu Linux, in case that helps.
To set breakpoints with the command line, dbstop is the tool (plus dbclear to clear breakpoints and dbstatus to list them).
There are presently 17 different forms to dbstop, which allow you to specify various combinations of:
The M-file in which to stop
Line number
Sub-function
Conditional to an arbitrary expression. For example,
dbstop in myFun.m at 224 if ~exist('x','var')
At any run-time error (dbstop if error)
At a specific error (e.g dbstop if error myFun.m:barErrorId)
At any warning (dbstop if warning) or specific warning
If NaN or Inf are encountered (dbstop if naninf)
See the documentation for dbstop for details and good examples.
Also get used to dbcont (or F5), dbstep (or F10), dbquit (Shift+F5), dbstep (also dbstep in, dbstep out), dbstack (to see where you are and how you got there). The keyboard shortcuts may be different outside of Windows.
Far less used, but still very useful are dbup and dbdown, which allow you to switch workspace context (memory stacks).
See the summary of functions and a list of examples and how-to pages in the MathWorks page on Debugging.
Related to the "db" functions is checkcode, which will check your code for possible problems before you even run it. This is a nice substitute for the red squiggly underlines that you would get in the MATLAB Editor.
Once you get a hang of dbstop and it's syntax, you won't often need to insert a keyboard into your code, but it's always an option.
Try placing the keyboard command in your code to insert a breakpoint. When the keyboard command is reached, MATLAB will drop into an interactive prompt that you can use to inspect variables. For example:
x = rand(10,10);
y = rand(10,5);
z = x * y;
keyboard; % you can interactively inspect x, y, z here
z = sort(z);
To leave keyboard mode, you can type dbquit to exit the program, or return to continue executing the program.
Another trick is to turn on dbstop if error which will automatically drop you into an interactive prompt whenever your code crashes.
You can use MATLAB -Dgdb if that helps. This sets gdb as the debugger. You will need to be familiar with gdb of course.
Once you do that, use the standard gdb commands to debug it.
EDIT
My mistake. Above won't work for M-Files. (Not having MATLAB to try things out is a pain :)
MATLAB has a pretty good set of debugging commands you can use from the commandline. If you insert keyboard commands in your MATLAB code, you can then use the commands.
You can use MATLAB's editor debug button to debug within MATLAB environment
A lot of the code that I write in Matlab has a very verbose output. As the program runs, information is printed to the command window, and with each new line, the window automatically scrolls to the bottom. This becomes a problem when I want to read some of the output more closely or scroll up to look at older output. I can scroll up, but only until a new line is printed, which is often less than a second.
Does anyone know if it is possible to turn off this automatic scrolling in the Matlab window? I work in a number of different Matlab versions, depending on the machine, and this happens with all of them. The answer to this might be "No", but I swear I remember having this functionality at one point.
Use the more function: http://www.mathworks.com/help/matlab/ref/more.html
more on
Then run your program. Press spacebar when you wish to see more of the output.
more off will turn it off.
You may find this workaround useful.
First launch matlab using the command line matlab -logfile 'myLog.txt' (the doc says it "starts MATLAB and makes a copy of any output to the Command Window in filename. This includes all crash reports.")
Then open your .txt file using a text editor supporting automatic refresh of content (see picture). On OSX I use TextWrangler (freely available at www) but others have been reported to have this feature (see here or here).
Results: output displays (fprintf, disp, but not the commands per se) are printed both on the Matlab console and the text editor (file is refreshed with a little lag time, below half a second I would say with my configuration). And there is no automatic scrolling. Such procedure does not seem to impact the overall performance of the script (although it may deserve some testing).
Context
Have some transcript files from terminal interaction, obtained using traditional Unix command "script".
Those transcripts contain lots of control character (like backspace when editing shell commands), and lots of color code sequences as result of running various commands. Occasionally, even colorful full-terminal (ncurses-based) applications like "emacs -nw" or "aptitude" were run.
At program runtime, TERM environment variable was set as "xterm".
Need 1: read (more or less solved)
I need to read those files again and sometimes copy-paste some small parts.
The trouble is : while one color change here and there is not so much of a problem, their actual density makes the output barely readable. Worse, edited command lines (with cursor jumps and edited words) are completely unreadable.
"Okay" solution
Browse through files using e.g. "less -r". Paging forward in the same terminal setup reproduces the various color and character style.
But many other features come out more or less broken, e.g. search backwards produces jumbled terminal output, often have to pres "Ctrl-L" to clean thing up.
Need 2: editing
My preferred editor is emacs. Some people have had a similar situation when running the shell inside emacs, e.g. Something wrong with Emacs shell.
Here is not the same situation. Examples of differences: here we don't have to run an actual shell, but we need to move cursor freely like in usual editing.
Editing here means easily open such a transcript file in editor and then:
at all times through editing, see character changes (color, attributes) as conveyed by the terminal codes
(optional) some character that are neighbour on the terminal grid but are separated in file by some control characters would have a visual hint about this
ability to insert some text,
delete sections,
use all editor features like search/replace etc.
copy & paste to & from file (including to external programs, which would receive just plain text)
in my wildest dreams, some kind of "flatten" action, like select a sequence with a heavily edited command line and replace it with a simple series of characters as if it was typed in one run. "Visual hints" mentioned above would disappear.
Type Alt-: to evaluate something in the minibuffer. Evaluate (ansi-color-apply-on-region (point-min) (point-max)) and it will convert ansi color codes to be font colors.