Mercurial > vim
view runtime/doc/usr_50.txt @ 33083:79b2eb83f2df v9.0.1827
patch 9.0.1827: xxd: no color support
Commit: https://github.com/vim/vim/commit/e2528ae11134cdf35c312754b124aba4963d8054
Author: Aapo Rantalainen <aapo.rantalainen@gmail.com>
Date: Thu Aug 31 17:58:13 2023 +0200
patch 9.0.1827: xxd: no color support
Problem: xxd: no color support
Solution: Add color support using xxd -R
Add some basic color support for xxd
The hex-value and value are both colored with the same color depending
on the hex-value, e.g.:
0x00 = white
0xff = blue
printable = green
non-printable = red
tabs and linebreaks = yellow
Each character needs 11 more bytes to contain color. (Same color in a
row could contain only one overhead but the logic how xxd creates colums
must be then changed.) Size of colored output is increased by factor of
~6. Also grepping the output will break when colors is used.
Flag for color is "-R", because less uses "-R".
Color uses parameters auto,always,never same as less and grep (among
others).
E.g.
xxd -R always $FILE | less -R
Add some screen-tests (that currently on work on linux) to verify the
feature works as expected.
closes: #12131
Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Aapo Rantalainen <aapo.rantalainen@gmail.com>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Thu, 31 Aug 2023 18:15:03 +0200 |
parents | f8116058ca76 |
children | 4635e43f2c6f |
line wrap: on
line source
*usr_50.txt* For Vim version 9.0. Last change: 2022 Jun 20 VIM USER MANUAL - by Bram Moolenaar Advanced Vim script writing |50.1| Exceptions |50.2| Function with variable number of arguments |50.3| Restoring the view Next chapter: |usr_51.txt| Create a plugin Previous chapter: |usr_45.txt| Select your language (local) Table of contents: |usr_toc.txt| ============================================================================== *50.1* Exceptions Let's start with an example: > try read ~/templates/pascal.tmpl catch /E484:/ echo "Sorry, the Pascal template file cannot be found." endtry The `read` command will fail if the file does not exist. Instead of generating an error message, this code catches the error and gives the user a message with more information. For the commands in between `try` and `endtry` errors are turned into exceptions. An exception is a string. In the case of an error the string contains the error message. And every error message has a number. In this case, the error we catch contains "E484:". This number is guaranteed to stay the same (the text may change, e.g., it may be translated). Besides being able to give a nice error message, Vim will also continue executing commands after the `:endtry`. Otherwise, once an uncaught error is encountered, execution of the script/function/mapping will be aborted. When the `read` command causes another error, the pattern "E484:" will not match in it. Thus this exception will not be caught and result in the usual error message and execution is aborted. You might be tempted to do this: > try read ~/templates/pascal.tmpl catch echo "Sorry, the Pascal template file cannot be found." endtry This means all errors are caught. But then you will not see an error that would indicate a completely different problem, such as "E21: Cannot make changes, 'modifiable' is off". Think twice before you catch any error! Another useful mechanism is the `finally` command: > var tmp = tempname() try exe ":.,$write " .. tmp exe "!filter " .. tmp :.,$delete exe ":$read " .. tmp finally delete(tmp) endtry This filters the lines from the cursor until the end of the file through the "filter" command, which takes a file name argument. No matter if the filtering works, if something goes wrong in between `try` and `finally` or the user cancels the filtering by pressing CTRL-C, the `delete(tmp)` call is always executed. This makes sure you don't leave the temporary file behind. The `finally` does not catch the exception, the error will still abort further execution. More information about exception handling can be found in the reference manual: |exception-handling|. ============================================================================== *50.2* Function with variable number of arguments Vim enables you to define functions that have a variable number of arguments. The following command, for instance, defines a function that must have 1 argument (start) and can have up to 20 additional arguments: > def Show(start: string, ...items: list<string>) The variable "items" will be a list in the function containing the extra arguments. You can use it like any list, for example: > def Show(start: string, ...items: list<string>) echohl Title echo "start is " .. start echohl None for index in range(len(items)) echon $" Arg {index} is {items[index]}" endfor echo enddef You can call it like this: > Show('Title', 'one', 'two', 'three') < start is Title Arg 0 is one Arg 1 is two Arg 2 is three ~ This uses the `echohl` command to specify the highlighting used for the following `echo` command. `echohl None` stops it again. The `echon` command works like `echo`, but doesn't output a line break. If you call it with one argument the "items" list will be empty. `range(len(items))` returns a list with the indexes, what `for` loops over, we'll explain that further down. ============================================================================== *50.3* Restoring the view Sometimes you want to jump around, make a change and then go back to the same position and view. For example to change something in the file header. This can be done with two functions: > var view = winsaveview() # Move around, make changes winrestview(view) ============================================================================== Next chapter: |usr_51.txt| Create a plugin Copyright: see |manual-copyright| vim:tw=78:ts=8:noet:ft=help:norl: