Support ! and ~ prefixes in the lua script, and edit readme.

Readme.html

@@ -2734,15 +2734,22 @@ the creature.</p>
 </div>
 <div class="section" id="lua">
 <h2><a class="toc-backref" href="#id129">lua</a></h2>
-<dl class="docutils">
-<dt>There are three ways to invoke this command:</dt>
-<dd><ol class="first last arabic simple">
-<li>without any parameters - starts an interactive lua interpreter</li>
-<li>-f &quot;filename&quot; or --file &quot;filename&quot; - loads and runs the file indicated by filename</li>
-<li>-s [&quot;filename&quot;] or --save [&quot;filename&quot;] - loads and runs the file indicated by filename from save directory. If filename is not supplied it loads &quot;dfhack.lua&quot;</li>
+<p>There are the following ways to invoke this command:</p>
+<ol class="arabic">
+<li><p class="first"><tt class="docutils literal">lua</tt> (without any parameters)</p>
+<p>This starts an interactive lua interpreter.</p>
+</li>
+<li><p class="first"><tt class="docutils literal">lua <span class="pre">-f</span> &quot;filename&quot;</tt> or <tt class="docutils literal">lua <span class="pre">--file</span> &quot;filename&quot;</tt></p>
+<p>This loads and runs the file indicated by filename.</p>
+</li>
+<li><p class="first"><tt class="docutils literal">lua <span class="pre">-s</span> [&quot;filename&quot;]</tt> or <tt class="docutils literal">lua <span class="pre">--save</span> [&quot;filename&quot;]</tt></p>
+<p>This loads and runs the file indicated by filename from the save
+directory. If the filename is not supplied, it loads &quot;dfhack.lua&quot;.</p>
+</li>
+<li><p class="first"><tt class="docutils literal">:lua</tt> <em>lua statement...</em></p>
+<p>Parses and executes the lua statement like the interactive interpreter would.</p>
+</li>
 </ol>
-</dd>
-</dl>
 </div>
 <div class="section" id="embark">
 <h2><a class="toc-backref" href="#id130">embark</a></h2>

Readme.rst

@@ -1922,10 +1922,25 @@ the creature.
 
 lua
 ===
-There are three ways to invoke this command:
- 1. without any parameters - starts an interactive lua interpreter
- 2. -f "filename" or --file "filename" - loads and runs the file indicated by filename
- 3. -s ["filename"] or --save ["filename"] - loads and runs the file indicated by filename from save directory. If filename is not supplied it loads "dfhack.lua"
+
+There are the following ways to invoke this command:
+
+1. ``lua`` (without any parameters)
+
+   This starts an interactive lua interpreter.
+
+2. ``lua -f "filename"`` or ``lua --file "filename"``
+
+   This loads and runs the file indicated by filename.
+
+3. ``lua -s ["filename"]`` or ``lua --save ["filename"]``
+
+   This loads and runs the file indicated by filename from the save
+   directory. If the filename is not supplied, it loads "dfhack.lua".
+
+4. ``:lua`` *lua statement...*
+
+   Parses and executes the lua statement like the interactive interpreter would.
 
 embark
 ======

scripts/lua.lua

@@ -1,11 +1,15 @@
+-- Execute lua commands interactively or from files.
+
 local args={...}
-if args[1]=="--file" or args[1]=="-f" then
+local cmd = args[1]
+
+if cmd=="--file" or cmd=="-f" then
     local f,err=loadfile (args[2])
     if f==nil then
         qerror(err)
     end
     dfhack.pcall(f,table.unpack(args,3))
-elseif args[1]=="--save" or args[1]=="-s" then
+elseif cmd=="--save" or cmd=="-s" then
     if df.global.world.cur_savegame.save_dir=="" then
         qerror("Savefile not loaded")
     end
@@ -16,12 +20,27 @@ elseif args[1]=="--save" or args[1]=="-s" then
         qerror(err)
     end
     dfhack.pcall(f,table.unpack(args,3))
-elseif args[1]~=nil then
-    local f,err=load(args[1],'=(lua command)', 't')
+elseif cmd~=nil then
+    -- Support some of the prefixes allowed by dfhack.interpreter
+    local prefix
+    if string.match(cmd, "^[~!]") then
+        prefix = string.sub(cmd, 1, 1)
+        cmd = 'return '..string.sub(cmd, 2)
+    end
+
+    local f,err=load(cmd,'=(lua command)', 't')
     if f==nil then
         qerror(err)
     end
-    dfhack.pcall(f,table.unpack(args,2))
+
+    local rv = table.pack(dfhack.safecall(f,table.unpack(args,2)))
+
+    if rv[1] and prefix then
+        print(table.unpack(rv,2,rv.n))
+        if prefix == '~' then
+            printall(rv[2])
+        end
+    end
 else
     dfhack.interpreter("lua","lua.history")
 end