Mechanism to automatically infer current file for build / test

[dbarnett]

It would be nice if the bazel plugin could infer "the target for the current file" automatically so you could just invoke :Bazel build or :Bazel test as a shortcut for "build this file's build target" and "run the test defined in this file".

[dbarnett]

Also inferring "current test method" would be good, but we can ignore that for v1 since there's some complexity getting that right and exposing it cleanly as a feature.

[manneorama]

@dbarnett I don't know vimscript nearly well enough to make a pull request (also, i use Vundle which this plugin doesn't seem to support), but I made these functions for doing just that in my .vimrc.

function! BazelGetCurrentBufTarget()
    let bazel_file_label=system("bazel query " . bufname("%") . " --color no --curses no --noshow_progress | tr -d '[:space:]'")
    let bazel_file_package=split(bazel_file_label, ":")[0]
    let g:current_bazel_target=system("bazel query \"attr('srcs', " . bazel_file_label . ", " . bazel_file_package . ":*)\" --color no --curses no --noshow_progress | tr -d '[:space:]'")
endfunction

function! BazelBuildHere()
    :call  BazelGetCurrentBufTarget()
    :execute '!bazel build ' . g:current_bazel_target
endfunction

function! BazelTestHere()
    :call BazelGetCurrentBufTarget()
    :execute '!bazel test ' . g:current_bazel_target
endfunction