     cmd:
         vacuum: (nm)->
             nm ?= null
-            $ =
+            $$ =
                 node: 'cmd'
                 type: 'vacuum'
                 nm: nm
         begin_trans: (transtype, trans_opt)->
-            $ =
+            $$ =
                 node: 'begin_trans'
                 transtype: transtype
                 trans_opt: trans_opt
         commit_trans: (trans_opt)->
-            $ =
+            $$ =
                 node: 'commit_trans'
                 trans_opt: trans_opt
         end_trans: (trans_opt)->
-            $ =
+            $$ =
                 node: 'end_trans'
                 trans_opt: trans_opt
         reindex: (nm, dbnm)->
             nm ?= null
             dbnm ?= null
-            $ =
+            $$ =
                 node: 'reindex'
                 nm: nm
                 dbnm: dbnm

    ecmd: (explain, cmd)->
        explain ?= null
        cmd ?= null
        $ =
            node: 'ecmd'
            explain: explain
            cmd: cmd
    explain: (explain, queryPlan)->
        $ =
            node: 'explain'
            explain: explain
            queryPlan: queryPlan

            terminal: terminal

    dbnm: (nm)->
        $$ =
            node: 'dbnm'
            nm: nm

    trans_opt: (nm)->
        nm ?= null
        $$ =
            node: 'trans_opt'
            value: nm

    transtype: (type)->
        type ?= null
        $$ =
            node: 'transtype'
            type: type

