subx.vim


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75

" SubX syntax file
" Language:    SubX
" Maintainer:  Kartik Agaram <mu@akkartik.com>
" URL:         https://github.com/akkartik/mu
" License:     public domain
"
" Copy this file into your ftplugin directory, and add the following to your
" vimrc or to .vim/ftdetect/subx.vim:
"   autocmd BufReadPost,BufNewFile *.subx set filetype=subx
"
" Some highlight groups you might want to select colors for in your vimrc:
"   subxFunction
"   subxMinorFunction
"   subxTest
"
" Optionally, devote more colors to different kinds of comments. Some suggestions
" for 256-color terminals to add to your vimrc:
"   blue tones:
"     highlight subxH1Comment cterm=underline ctermfg=27
"     highlight subxComment ctermfg=27
"     highlight subxS1Comment ctermfg=19
"     highlight subxS2Comment ctermfg=245
"   blue-green tones
"     highlight subxH1Comment cterm=underline ctermfg=25
"     highlight subxComment ctermfg=25
"     highlight subxS1Comment ctermfg=19
"     highlight subxS2Comment ctermfg=245
"   grey tones
"    highlight subxH1Comment cterm=bold,underline
"    highlight subxComment cterm=bold ctermfg=236
"    highlight subxS1Comment cterm=bold ctermfg=242
"    highlight subxS2Comment ctermfg=242

let s:save_cpo = &cpo
set cpo&vim

" setlocal iskeyword=@,48-57,?,!,_,$,-
setlocal formatoptions-=t  " allow long lines
setlocal formatoptions+=c  " but comments should still wrap

setlocal iskeyword+=-,?,<,>,$,@

syntax match subxH1Comment /# - .*/ | highlight link subxH1Comment Comment
syntax match subxComment /#\( \.\| - \|? \)\@!.*/ | highlight link subxComment Comment
syntax match subxS1Comment /# \..*/ | highlight link subxS1Comment Comment
syntax match subxS2Comment /# \. \..*/ | highlight link subxS2Comment Comment

set comments-=:#
set comments+=n:#
syntax match subxCommentedCode "#? .*"  | highlight link subxCommentedCode CommentedCode | highlight link CommentedCode Comment
let b:cmt_head = "#? "

" comment token
syntax match subxDelimiter / \. /  | highlight link subxDelimiter Normal

syntax match subxString %"[^"]*"% | highlight link subxString Constant

"" definitions
" match globals but not registers like 'EAX'
" don't match capitalized words in metadata
" don't match inside strings
syntax match subxGlobal %\(/\)\@<!\<[A-Z][a-z0-9_-]*\>% | highlight link subxGlobal SpecialChar

" functions but not tests, globals or internal functions
syntax match subxFunction "^\(test_\)\@<![a-z][^ ]*\(:\)\@=" | highlight link subxFunction Function
" tests starting with 'test-'; dark:34 light:64
syntax match subxTest "^test-[^ ]*\(:\)\@=" | highlight link subxTest Typedef
" internal functions starting with '_'
syntax match subxMinorFunction "^_[^ ]*\(:\)\@=" | highlight link subxMinorFunction Ignore
" other internal labels starting with '$'
syntax match subxLabel "^\$[^ ]*\(:\)\@=" | highlight link subxLabel Constant

syntax keyword subxControl break loop | highlight link subxControl Constant

let &cpo = s:save_cpo
The "cd-after-exit" Feature
===========================

Abstract
--------

This document explains the troublesome implementation of the "cd-after-exit"
feature.

This is written for developers who wonder how it's working.


Specification
-------------

When the feature is enabled, ranger will attempt to change the directory of
the parent shell (from which ranger is run) to the last visited directory
when ranger is exited.

This task is, by its nature, shell dependent.  As a bash or zsh user,
I focused on the implementation for those two shells and left the
addition of support for csh, ksh, and other shells to those who actually use
those shells.


What's the problem?
-------------------

Shells have several limitations, the implementation could not be done easily
because:

1. It is not possible to use something like system('cd xyz') at the end.
This command would run in a new shell and wouldn't change the directory
of the parent shell at all.

2. Using exec('cd xyz') is not possible either, since 'cd' is a command
which is directly integrated in to the shell and can not be run this way.


Redirection of streams
----------------------

The only way I found is using cd `program` from inside the shell to change
the directory to whatever `program` prints to the stdout:

    bash$ cd `echo ..`

Since the user interface still has to be printed, we simply redirect it to
the stderr.  It is not sufficient however to change sys.stdout to sys.stderr,
since curses seems not to be aware of sys.stdout and continues to print out
the interface to the actual stdout.

So what I did was swap the stdout and stderr of the whole ranger process on
the shell command line by using:

    bash$ cd `ranger 3>&1 1>&2 2>&3 3>&-`

Since errors are now printed to the stdout, we have do this in ranger:
    sys.stderr = sys.__stdout__

And at the end, write the current directory to the stdout, which is now
reachable via sys.__stderr__ due to the redirections:
    sys.__stderr__.write(last_visited_directory)

To inform the ranger process about these changes, we add a --cd-after-exit
switch which:
    bash$ cd `ranger --cd-after-exit 3>&1 1>&2 2>&3 3>&-`


Argument passing
----------------

This works well enough, but there are two remaining problems:

1. How to pass arguments to ranger?

2. How to memorize that line? Although you can just copy+paste it
into your bashrc and create an alias, the complexity of the line
could lead to errors.

Both problems are solved by putting the command in a file:

run.sh:
    cd "`ranger --cd-after-exit \"$@\" 3>&1 1>&2 2>&3 3>&-`"

The $@ is responsible for argument passing.  By using the source command,
the file will be evaluated without creating a distinct new shell.

    bash$ source run.sh arg1 ... argN

To add flexibility, replace the name "ranger" in the command to the first
argument.  Now it requires you to pass the name of the ranger command to
the script as the first argument:

run.sh:
    RANGER="$1"
    shift
    cd "`$RANGER --cd-after-exit \"$@\" 3>&1 1>&2 2>&3 3>&-`"


Put it in a nutshell
--------------------

I didn't want to have 2 files for the main program and wanted just one
file at /usr/bin/ranger.  So I used this trick to merge both files into one:

    #!/usr/bin/python
    """":
    <shell code>
    """
    <python code>

If you run this file with python, or simply by typing ranger, the program will
run normally.  If you, however, run this file by sourcing it into the shell,
like you did with run.sh, the cd-after-exit mode will be activated.

Now the way of running ranger with the cd-after-exit feature is:

    bash$ source /path/to/ranger.py /path/to/ranger.py

or, if properly installed:

    bash$ source ranger ranger

A convenient way of using this feature is adding this line to your bashrc:

    alias rn='source ranger ranger'


Open issues
-----------

Unfortunately there is some redundancy: you have to type the path to ranger
twice.  I know of no way to fix this, because it is not possible to get the
filename of the file currently being sourced.

Example:

    bash$ echo 'source sourced.sh' > main.sh
    bash$ echo 'echo $0 $@' > sourced.sh
    bash$ bash main.sh
    main.sh

If you find a way to make this print out 'sourced.sh', let me know. :)

Another thing: If Ctrl+C is pressed anywhere in the program, the execution
of the sourced shell script is stopped and the feature stops working.

This was handled by using a script like that:

    ranger_exec="$1"
    shift
    trap "" INT
    exec 3< <($ranger_exec --cd-after-exit $@ 3>&1 1>&2 2>&3 3>&-)
    while read ranger_output; do false; done <&3
    cd "$ranger_output"
    #...and some clean ups

but that won't work in zsh for some reason, so I took it out again.

Dec 25, 2009