6 Parsing without the GUI

The parser can also be used without the GUI, e.g. as a syntactic module in a bigger NLP system. For instance, an earlier version of our parser has been used in a software project described in Building a Text Adventure on Description Logic. In this package, we provide the file "TEST.oz" which is an illustrative example of how to use the parser without the GUI. In the following, we give a walkthrough of "TEST.oz".

Firstly, to invoke the parser without the GUI, one needs to import or link the functor "Grammar.ozf", which must then be set up with a grammar file:

   [Grammar] = {Module.link ['Grammar.ozf']}
   {Grammar.set 'grammar-de.dg'}
   G = {Grammar.get}   

As a result, the variable G denotes the compiled grammar file information of "grammar-de.dg".

Next, the functor "Script.ozf" must be imported or linked:

   [Script] = {Module.link ['Script.ozf']}

Optionally, a plugins file can also be imported or linked, as in the following example:

   [Plugins] = {Module.link ['Plugins-de.ozf']}   
   proc {PluginsProc Signs G}
      {Plugins.plugins.relative.procedure Signs true G}
      {Plugins.plugins.root.procedure Signs norestr G}
   end

Here, we link the plugins file "Plugins-de.ozf". Then, we define the procedure PluginsProc which in turn calls the individual constraints relative and root. The relative-constraint is given parameter true and the root-constraint the parameter norestr.

In the following code snipped, we set the parser's parameters:

   Params = o(
         generate: false
	       
         idacc: true
         idval: true
         idgamma: true

         lporder: true
         lpproj: true
         lpacc: true
         lpval: true
         lpnode: true
         lpgamma: true

         climbing: true
	 subtrees: true
	 barriers: true

         plugins: PluginsProc)

Any of these parameters can be omitted. If so, the parameter is assigned precisely a default value as defined for the GUI (see chapter 5.4). If the plugins parameter is omitted, no plugin constraints are applied.

Finally, we define the string Words and initialize the parser using the function Script.make which returns a parse script. This script must now be invoked by an Oz search engine: in the example, we use the standard search engine to find all solutions for the string (Search.base.all):

   Words = [maria liebt einen reichen mann]
   S = {Script.make Words Params G}
   Solutions = {Search.base.all S}

After parsing, the variable Solutions is unified with the list of all solutions. A solution is in turn a list of Signs.