I wrote a small program to read input, and print the result, and loop. Like REPL.
And I want to get the input I have inputed before when I press the up key on the keyboard and edit this input, like what bash or zsh does. I have no idea about the implementation. I also searched the web but no result I want. Could someone point a way for me? Or give me some articles to read?
The point is: How to print an EDITABLE line on screen?
I have no personal experience with it, but it's my understanding that Term::ReadLine provides command editing functionality with history. It's even part of the perl distribution.
You just need to:
Store a history of user input, just like bash and zsh do;
Listen for ↑ key presses, just like bash and zsh do;
Display the last command when ↑ is pressed. Just like, you guessed it, bash and zsh.
This is what programming is all about: breaking down big problems we don't know how to solve into smaller problems that we do know how to solve, or can more-easily figure out how to solve. So if you don't know how to do any of the things I listed above, try writing some code, reading API documentation, looking for answers on Google/Stack Overflow, or – once again – breaking them down into sub-problems.
if your point is "print" maybe you need Term::Screen. example code here: code.
otherwise if your point is "history", man/perldoc Term::ReadLine.
Related
I'm working on a PowerShell profile template that mimics the lambda mod for zsh as close as possible as a proof-of-concept.
I was able to get the lambda, the user colored if root and the home-abbreviated path right. The git part can be done using posh-git, but the repo hash displayed in the mod is right aligned in the prompt line.
Zash/Bash does this through a RPROMPT variable and I haven't found similar functionality in PowerShell. Does it really not exist? Is it possible to implement it?
If I were to implement how'd it go about? It seems to me it's impossible to reliably align something right on PS without the Shell size (and therefore breaking at resize). Also, I wouldn't know how to have the cursor still on the line that RPROMPT was written.
Before I get reamed for this, I know there are some posts detailing how to clear ALL the output from a cell, but I'm interested in only clearing part of it.
Let me provide some background. I am creating a word-guessing game like LINGO where the user is prompted to guess a five-letter word, then using CSS to provide some visual feedback as to which letters are in the correct position, and which letters are in the word but in the wrong position. The way my program is structured, it displays the feedback after each guess and then prompts the user again and displays the guess. So something like this:
Guess a word: word
FEEDBACK
guess again: word
FEEDBACK
...
You get the picture. My goal is to come as close to duplicating LINGO as possible, which would mean removing the user input from the screen after it has been submitted and having it show a sequence of feedback. This to me means one of three things:
1) Find a way to clear part of the output
2) Find a way to prompt the user for text input without displaying it on the screen
3) Cache the user input, delete the all the output after each iteration, and display the cached guesses.
I've researched 1 and 2 and haven't been able to find anything. 3 would be a PITA so before I went to the trouble I thought I would ask.
1 think is either not possible or very difficult - it's hard in regular python, never mind Jupyter. In regular python, you'd probably use something like curses but I tried it in Jupyter and it affects the console Jupyter is running from - not the stdout in the notebook.
If you really wanted 2, you could probably write your own version of input that uses carriage return \r after stripping the trailing newline via writing a function that loops listening for keystrokes and submitting once a newline is pressed. The carriage return should mean that the next line overwrites the previous line.
3 Caching the input shouldn't be too difficult though I presume? Just store them in an array or something then you can display them back to the user after using IPython.display.clear_output.
I have a problem. I want to execute some commands in the Commandline of linux. I tested TProcess (So i am using Lazarus) but now when i am starting the programm, there is nothing, wich the Program do.
Here is my Code:
uses [...], unix, process;
[...]
var LE_Path: TLabeledEdit;
[...]
Pro1:=TProcess.Create(nil);
Pro1.CommandLine:=(('sudo open'+LE_Path.Text));
Pro1.Options := Pro1.Options; //Here i used Options before
Pro1.Execute;
With this Program, i want to open Files with sudo (The Programm is running on the User Interface)
->Sorry for my Bad English; Sorry for fails in the Question: I am using StackOverflow the first time.
I guess the solution was a missing space char?
Change
Pro1.CommandLine:=(('sudo open'+LE_Path.Text));
to
Pro1.CommandLine:=(('sudo open '+LE_Path.Text));
# ----------------------------^--- added this space char.
But if you're a beginner programmer, my other comments are still worth considering:
trying to use sudo in your first bit of code may be adding a whole extra set of problems. SO... Get something easier to work first, maybe
/bin/ls -l /path/to/some/dir/that/has/only/a/few/files.
find out how to print a statement that will be executed. This is the most basic form of debugging and any language should support that.
Your english communicated your problem well enough, and by including sample code and reasonable (not perfect) problem description "we" were able to help you. In general, a good question contains the fewest number of steps to re-create the problem. OR, if you're trying to manipulate data,
a. small sample input,
b. sample output from that same input
c. your "best" code you have tried
d. your current output
e. your thoughts about why it is not working
AND comments to indicate generally other things you have tried.
When running emacs calc, typing a prefix key, say 'm', followed by '?' is supposed to show all mode-related commands in the minibuffer as a kind of quick help facility.
For several years I have noticed that this quit working for me. When I hit the '?' the minibuffer flashes the help for a small fraction of a second, then goes blank. I can sometimes see parts of the help text rendered but ususally it blanks too fast to see it.
This does not happen when I run emacs -Q to skip my init file, so it is something in the init file that is the cuplprit.
My init file is quite large. I would like to put something like '(exit)' in different places in my init file to stop processing the init file and see if I can pin down what is causing the problem.
(1) What is the right way to do this?
(2) Anybody else see this problem with the minibuffer in calc?
Good question. The answer is simple: recursively bisect your init file.
Do that by commenting out 1/2 of it, then 3/4, then 7/8,... This is a binary search, and it is very quick, even though it might not seem that way at first. It is systematic, and essentially blind (thoughtless).
To comment out a block of text, use command comment-region. To uncomment a block of text, use C-u with the same command.
Trust me - in no time at all, you will have identified the culprit code, no matter how big your init file is. And if you load other libraries from your init file, and doing the exercise above shows that the culprit code is in one of those libraries, then do the same thing with (a copy of) that library code: recursively bisect it.
After several hours of trying to narrow down the problem, I found the culprit.
When key-chord-mode is set on in calc, the key help facility displays the symptoms I mentioned above.
Would like to keep key-chord enabled globally and disable it in calc-mode, but turning it off in the calc-mode-hook turns it off for all modes. Any ideas?
Anyway, I am closer to figuring out this long-term irritant.
Every time when I finish running a matlab code collection on command line, when I exit matlab, the standard output just gets messed. I can still use the terminal window, but whatever I typed won't show up on the screen, leaving me either type with my eyes blind, or open up a new terminal and excessively cd to the old place.
This happens every single time when I use make to run a matlab collection, and since I'm working a lot on this, it turns out to be very annoying. Does anyone know what's the problem here and how should I fix it?
As was pointed out in the comments, the makescript is probably dumping "bad" characters to the terminal. You could prevent this (but possibly lose useful information) by redirecting the output - instead of sending it to the terminal window, you can send it to a file, or even /dev/null ("the great bit bucket in the sky").
The underlying problem, however, is that your makefile is even sending these characters to the terminal in the first place. I would recommend that you pipe the output to a file with something like make > myDump.txt, then examine the resulting file to see what is going on, and where in your makefile the problem is created. It is possible that you will still be getting some output when you do this - that's because by default > redirects stdout only, and not stderr - a second output stream used for error messages. You can redirect both to a file with make 2>&1 myDump.txt.
You have already seen the recommendation to use stty sane to restore the status of the terminal - I am repeating it here in case someone only looks at answers, and not at comments; but I don't take credit for it :-).