Tutorial :Vim: sourcing based on a string



Question:

I can't seem to find an answer to this in any of the numerous Vim scripting tutorials online. What I want to do is construct a file name of a script from environment variables and then source it. And I want to do it in Vim.

If I were to do it in a shell I'd do something like this:

source ${HOME}/.vim/myscript_${FOO}.vim  

How do I do it in Vim?


Solution:1

You can build up a string and then use the execute command:

exec "source " . $HOME . "/.vim/myscript_" . l:foo . ".vim"  

(The l:foo here is an example of using a local variable from within a function.)


Edit:

But in fact exec is overkill in this specific case. As rampion shows here, the OPs task can be done directly with:

source $HOME/.vim/myscript_$FOO.vim  

Although vim does not let us wrap the variable names neatly in ${...} like we could in the shell, in this case we are lucky that HOME is terminated by the / and FOO by the .

In general, exec would be needed if you wanted to follow one of the variables by a non-terminating character. For example:

exec "source " . $BAR . "_script.vim"  

would insert the BAR variable, while the following would try to find a variable called BAR_script:

source $BAR_script.vim       " Possibly not what you wanted!  


Solution:2

Just :source works for me:

% export MYPATH='a/b/c'  % mkdir -p $MYPATH  % export MYFILE='temp.vim'  % cat > $MYPATH/$MYFILE  echo 'hello world'  ^D  % vim  :source $MYPATH/$MYFILE  hello world  

If you want to have some vim scripts automatically sourced though, just stick them in your ~/.vim/plugin/ directory, and they'll be loaded for you, without having to do it manually.

From :help expand-environment-var (which I got by doing :help environment and tab completing to the first likely result)

               *:set_env* *expand-env* *expand-environment-var*      Environment variables in specific string options will be expanded.  If the      environment variable exists the '$' and the following environment variable      name is replaced with its value.  If it does not exist the '$' and the name      are not modified.  Any non-id character (not a letter, digit or '_') may      follow the environment variable name.  That character and what follows is      appended to the value of the environment variable.  Examples: >         :set term=$TERM.new         :set path=/usr/$INCLUDE,$HOME/include,.      When adding or removing a string from an option with ":set opt-=val" or ":set      opt+=val" the expansion is done before the adding or removing.  

I tend to find vim's built in help more useful than anything else, but it does take a while to get the knack of knowing what to look for.


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