Add cargo#guessrun function & Cgrun command

This command attempts to guess which target you want to run, based on
the current buffer. If it is a bin target, it will run
`cargo run --bin <name> a:args`, an example target would be
`cargo run --example <name> a:args`, and if it is neither of these, or
the function can't be sure what it is, it falls back to just
`cargo run a:args`

Author: Paul Woolcock

autoload/cargo.vim

@@ -84,4 +84,32 @@ function! cargo#bench(args)
     call cargo#cmd("bench " . a:args)
 endfunction
 
+function! cargo#runtarget(args)
+    let l:filename = expand('%:p')
+    let l:read_manifest = system('cargo read-manifest')
+    let l:metadata = json_decode(l:read_manifest)
+    let l:targets = get(l:metadata, 'targets', [])
+    let l:did_run = 0
+    for l:target in l:targets
+        let l:src_path = get(l:target, 'src_path', '')
+        let l:kinds = get(l:target, 'kind', [])
+        let l:name = get(l:target, 'name', '')
+        if l:src_path == l:filename
+        if index(l:kinds, 'example') != -1
+            let l:did_run = 1
+            call cargo#run("--example " . shellescape(l:name) . " " . a:args)
+            return
+        elseif index(l:kinds, 'bin') != -1
+            let l:did_run = 1
+            call cargo#run("--bin " . shellescape(l:name) . " " . a:args)
+            return
+        endif
+        endif
+    endfor
+    if l:did_run != 1
+        call cargo#run(a:args)
+        return
+    endif
+endfunction
+
 " vim: set et sw=4 sts=4 ts=8:

doc/rust.txt

@@ -307,6 +307,9 @@ This plug defines very simple shortcuts for invoking Cargo from with Vim.
 :Cinstall <args>                                                 *:Cinstall*
                 Shortcut for 'cargo install`.
 
+:Cruntarget <args>                                                 *:Cruntarget*
+                Shortcut for 'cargo run --target' or 'cargo run --example',
+                depending on the currently open buffer.
 
 Formatting
 ----------

plugin/cargo.vim

@@ -18,6 +18,7 @@ command! -nargs=* Cupdate call cargo#update(<q-args>)
 command! -nargs=* Csearch  call cargo#search(<q-args>)
 command! -nargs=* Cpublish call cargo#publish(<q-args>)
 command! -nargs=* Cinstall call cargo#install(<q-args>)
+command! -nargs=* Cruntarget call cargo#runtarget(<q-args>)
 
 let &cpoptions = s:save_cpo
 unlet s:save_cpo