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diff --git a/doc/gf2.2-highlights.html b/doc/gf2.2-highlights.html index 7a1229cb1..58ccd5256 100644 --- a/doc/gf2.2-highlights.html +++ b/doc/gf2.2-highlights.html @@ -83,12 +83,91 @@ generated files created with other optimization flags. <p> -<b>Notice</b>: If you use the +<b>Important notice</b>: If you use the <a href="http://www.cs.chalmers.se/~bringert/gf/gf-java.html"> -Embedded GF Interpreter</a>, only the values <tt>none</tt> and -<tt>share</tt> can be used; the stronger optimizations are not +Embedded GF Interpreter</a>, +or the improved parsing algorithms described below, +only the values <tt>none</tt>, +<tt>share</tt> and <tt>values</tt> can be used; the stronger optimizations are not supported yet. +Also note that currently, GF aborts and reports an error if the stronger optimizations are used +when creating the grammar for the Embedded GF Interpreter, or when trying to parse. +<h3>Improved parsing algorithms</h3> + +We have implemented some of the suggested parsing algorithms described in +Peter Ljunglöf's <a href="http://www.cs.chalmers.se/~peb/pubs.html">PhD thesis</a>. +So now there are the following options for parsing: +<ul> + <li>The default parser. It uses a (possibly) very overgenerating context-free grammar, and filters the resulting parse trees by type-checking. + <li>The <tt>-cfg</tt> flag. It uses a much less overgenerating context-free grammar, and filters as above. + <li>The <tt>-mcfg</tt> flag. It uses an even less overgenerating <em>multiple context-free grammar</em>. + If the abstract syntax is context-free, meaning that there are no dependent types and only first-order functions, + the trees do not have to be filtered at all. +</ul> +The option <tt>-parser=X</tt> selects the parsing strategy. The default parser has the strategies +<tt>chart</tt>, <tt>bottomup</tt>, <tt>topdown</tt>, <tt>old</tt>, with the first one being the default. +The <tt>-cfg</tt> and <tt>-mcfg</tt> parsers only recognize the <tt>bottomup</tt> and <tt>topdown</tt> strategies. + +<p> + +<b>Note</b> that the <tt>-cfg</tt> and <tt>-mcfg</tt> parsers can take a very long time on their first call, since +they have to convert the GF grammar. This will only happen once in a GF run, provided the GF files are not changed. + +<p> + +<b>Tips</b> for choosing the best parser for your grammar. Try with the default parser; if it is too slow, try the other two. +Remember that the first time you parse they will be very slow, since they have to build parsing information. +the <tt>-cfg</tt> parser is best on grammars with many parameters and inflection tables, and +The <tt>-mcfg</tt> parser is even better when the grammar also has discontinuous constituents. + +<p> + +Here is a small example from the resource library: +<pre> +> i -src -optimize=share lib/resource/english/LangEng.gf +> p -cat=S "" +> p -cat=S -cfg "" +> p -cat=S -mcfg "" +{Comment: Just some dummy parsing calls to calculate the parsing information} + +> p -cat=S -rawtrees=200000 "you will be running" +{Comment: Nr of unfiltered trees: 169296 -- 99,996% av the trees are ill-typed} + +UseCl (PosTP TFuture ASimul) (SPredProgVP thou_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP thou_NP (IPredV ASimul run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP ye_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP ye_NP (IPredV ASimul run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP you_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP you_NP (IPredV ASimul run_V)) + +17730 msec + +> p -cat=S -cfg "you will be running" +{Comment: Nr of unfiltered trees: 246 -- 97,5% of the trees are ill-typed} + +UseCl (PosTP TFuture ASimul) (SPredProgVP thou_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP thou_NP (IPredV ASimul run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP ye_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP ye_NP (IPredV ASimul run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP you_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP you_NP (IPredV ASimul run_V)) + +1580 msec + +> p -cat=S -mcfg "you will be running" +{Comment: Nr of unfiltered trees: 6 -- all trees are type-corrent} + +UseCl (PosTP TFuture ASimul) (SPredProgVP thou_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP thou_NP (IPredV ASimul run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP ye_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP ye_NP (IPredV ASimul run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP you_NP (IPredV AAnter run_V)) +UseCl (PosTP TFuture ASimul) (SPredProgVP you_NP (IPredV ASimul run_V)) + +470 msec +</pre> + </body> </html> |