prompt: Add a Vi like prompt parser

Otherwise hooks that modify the command are not documented well
enough.

lib/awful/prompt.lua

@@ -65,6 +65,13 @@
 --
 -- @DOC_wibox_awidget_prompt_hooks_EXAMPLE@
 --
+-- *[Example two] Modifying the command (+ vi like input)*:
+--
+-- The hook system also allows to modify the command before interpreting it in
+-- the `exe_callback`.
+--
+-- @DOC_wibox_awidget_prompt_vilike_EXAMPLE@
+--
 --
 -- @author Julien Danjou <julien@danjou.info>
 -- @copyright 2008 Julien Danjou

tests/examples/wibox/awidget/prompt/vilike.lua

@@ -0,0 +1,55 @@
+local parent    = ... --DOC_NO_USAGE --DOC_HIDE
+local wibox     = require( "wibox"     ) --DOC_HIDE
+local awful     = { prompt = require("awful.prompt"),--DOC_HIDE
+                    util   = require("awful.util")}--DOC_HIDE
+local beautiful = require( "beautiful" ) --DOC_HIDE
+local terminal  = "xterm"  --DOC_HIDE
+
+    local atextbox = wibox.widget.textbox()
+
+    -- Store a list of verbs characters in a hash
+    local verbs = {
+        -- Spawn in a terminal
+        t = function(adjs, count, cmd) return {terminal, "-e", cmd} end,  --luacheck: no unused args
+        -- Spawn with a shell
+        s = function(adjs, count, cmd) return {awful.util.shell, '-c', cmd} end, --luacheck: no unused args
+    }
+
+    local function vi_parse(action, command)
+        local req, ret = {count={}, adjectives={}}
+        -- Quite dumb, don't do something like <num>+<adj>+<num>+<verb>
+        for char in action:gmatch('(.)') do
+            if     tonumber(char)  then table.insert(req.count, char)
+            elseif verbs[char]     then req.verb = char
+            else   table.insert(ret.adjectives, char) end
+            if req.verb then
+                req.count = tonumber(table.concat(req.count)) or 1
+                ret = ret or verbs[req.verb](req.adjectives, req.count, command)
+                req = {count={}, adjectives={}}
+            end
+        end
+        return ret
+    end
+
+    awful.prompt.run {
+        prompt       = '<b>Run: </b>',
+        text         = ':t htop', --DOC_HIDE
+        hooks        = {
+            {{},'Return', function(cmd)
+                if (not cmd) or cmd:sub(1,1) ~= ':' then return cmd end
+                local act, cmd2 = cmd:gmatch(':([a-zA-Z1-9]+)[ ]+(.*)')()
+                if not act then return cmd end
+                return vi_parse(act, cmd2)
+            end},
+        },
+        textbox      = atextbox,
+        history_path = awful.util.getdir('cache') .. '/history',
+        exe_callback = function(cmd) awful.spawn(cmd) end
+    }
+
+
+parent:add( wibox.widget {    --DOC_HIDE
+    atextbox,  --DOC_HIDE
+    bg = beautiful.bg_normal,  --DOC_HIDE
+    widget = wibox.container.background  --DOC_HIDE
+}) --DOC_HIDE