From 41aaed58d4734b7cec5a4d2567283cb818f77cbb Mon Sep 17 00:00:00 2001 From: bringert Date: Tue, 6 Dec 2005 16:23:29 +0000 Subject: Moved transfer documentation to doc/. Added sections and text to transfer tutorial and reference. Added script for generating html from txt2tags files. --- doc/transfer-tutorial.html | 210 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 210 insertions(+) create mode 100644 doc/transfer-tutorial.html (limited to 'doc/transfer-tutorial.html') diff --git a/doc/transfer-tutorial.html b/doc/transfer-tutorial.html new file mode 100644 index 000000000..7ca1c2060 --- /dev/null +++ b/doc/transfer-tutorial.html @@ -0,0 +1,210 @@ + + + + +Transfer tutorial + +

Transfer tutorial

+ +Author: Björn Bringert <bringert@cs.chalmers.se>
+Last update: Tue Dec 6 14:26:07 2005 + + +

Objective +
Abstract syntax +
Concrete syntax +
Generate tree module +
Write transfer code +
Compiling Transfer programs +
Using Transfer programs in GF +
+

+ +

Objective

+We want to write a Transfer program which we can use to do aggregation +in sentences which use conjugations on the sentence, noun phrase and +verb phrase levels. For example, we want to be able to transform +the sentence "John walks and Mary walks" to the sentence +"John and Mary walk". We would also like to transform +"John walks and John swims" to "John walks and swims". +

+Thus that what we want to do is: +

Transform sentence conjugation where the verb phrases in the sentences + are identical to noun phrase conjugation. +
Transform sentence conjugation where the noun phrases in the sentences + are identical to verb phrase conjugation. +

+ +

+This needs to be done recursively and thoughout the sentence, to be +able to handle cases like "John walks and Mary walks and Bill walks", and +"John runs and Mary walks and Bill walks". +

+FIXME: what about John walks and Mary runs and Bill walks"? +

+ +

Abstract syntax

+We will use the abstract syntax defined in +Abstract.gf. +

+ +

Concrete syntax

+There is an English concrete syntax for this grammar in +English.gf. +

+ +

Generate tree module

+To be able to write Transfer programs which sue the types defined in +an abstract syntax, we first need to generate a Transfer file with +a data type defintition corresponding to the abstract syntax. +This is done with the transfer grammar printer: +

+  $ gf
+  > i English.gf
+  > pg -printer=transfer | wf tree.tr
+

+Note that you need to load a concrete syntax which uses the abstract +syntax that you want to create a Transfer data type for. Loading just the +abstract syntax module is not enough. FIXME: why? +

+The command sequence above writes a Transfer data type definition to the +file tree.tr. +

+ +

Write transfer code

+We write the Transfer program +aggregate.tr. +

+FIXME: explain the code +

+ +

Compiling Transfer programs

+Transfer programs are written in the human-friendly Transfer language, +but GF only understands the simpler Transfer Core language. Therefore, +before using a Transfer program, you must first compile it to +Transfer Core. This is done using the transferc command: +

+  $ transferc -i<lib> <transfer program>
+

+Here, <lib> is the path to search for any modules which you import +in your Transfer program. You can give several -i flags. +

+So, to compile aggregate.tr which we created above, we use: +

+  $ transferc aggregate.tr
+

+The creates the Transfer Core file aggregate.trc. +

+ +

Using Transfer programs in GF

+ +

Loading the grammars

+To use a Transfer Core program to transform abstract syntax terms +in GF, you must first load the grammars which you want to use the +program with. For the example above, we need the grammar English.gf +and its dependencies. We load this grammar with: +

+  > i English.gf
+

+ +

Loading the Transfer program

+There are two steps to using a Transfer Core program in GF. First you load +the program into GF. This is done with the i command, which is also +used when loading grammar modules. To load the aggregate.trc which +we created above, we use: +

+  > i aggregate.trc
+

+ +

Calling Transfer functions

+To call a Transfer function on a term, we use the at command. +The at command takes the name of a Transfer function and an abstract +syntax term, and applies the function to the term: +

+  > at aggregS ConjS And (Pred John Walk) (Pred Mary Walk)
+  
+  Pred (ConjNP And John Mary) Walk
+

+Of course, the input and output terms of the at command can +be read from and written to pipes: +

+  > p "John walks and Mary walks" | at aggregS | l
+  
+  John and Mary walk
+

+To see what is going on between the steps, we can use -tr flags +to the commands: +

+  > p -tr "John walks and Mary walks" | at -tr aggregS | l
+  
+  ConjS And (Pred John Walk) (Pred Mary Walk)
+  
+  Pred (ConjNP And John Mary) Walk
+  
+  John and Mary walk
+

+ +

Transfer between different abstract syntaxes

+If the transfer function which you wan to call takes as input a term in one +abstract syntax, and returns a term in a different abstract syntax, you +can use the -lang flag with the at command. This is needed since the +at command type checks the result it produces, and it needs to +know which abstract sytnax to type check it in. +

+ + + + -- cgit v1.2.3