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updated tutorial and resource howto

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aarne
2006-06-15 23:05:42 +00:00
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@@ -7,7 +7,7 @@
<P ALIGN="center"><CENTER><H1>Grammatical Framework Tutorial</H1>
<FONT SIZE="4">
<I>Author: Aarne Ranta &lt;aarne (at) cs.chalmers.se&gt;</I><BR>
Last update: Wed Jan 25 16:03:03 2006
Last update: Fri Jun 16 01:02:28 2006
</FONT></CENTER>
<P></P>
@@ -34,7 +34,7 @@ Last update: Wed Jan 25 16:03:03 2006
<LI><A HREF="#toc15">Labelled context-free grammars</A>
<LI><A HREF="#toc16">The labelled context-free format</A>
</UL>
<LI><A HREF="#toc17">The ``.gf`` grammar format</A>
<LI><A HREF="#toc17">The .gf grammar format</A>
<UL>
<LI><A HREF="#toc18">Abstract and concrete syntax</A>
<LI><A HREF="#toc19">Judgement forms</A>
@@ -70,8 +70,8 @@ Last update: Wed Jan 25 16:03:03 2006
<UL>
<LI><A HREF="#toc42">Parameters and tables</A>
<LI><A HREF="#toc43">Inflection tables, paradigms, and ``oper`` definitions</A>
<LI><A HREF="#toc44">Worst-case macros and data abstraction</A>
<LI><A HREF="#toc45">A system of paradigms using ``Prelude`` operations</A>
<LI><A HREF="#toc44">Worst-case functions and data abstraction</A>
<LI><A HREF="#toc45">A system of paradigms using Prelude operations</A>
<LI><A HREF="#toc46">An intelligent noun paradigm using ``case`` expressions</A>
<LI><A HREF="#toc47">Pattern matching</A>
<LI><A HREF="#toc48">Morphological ``resource`` modules</A>
@@ -96,34 +96,41 @@ Last update: Wed Jan 25 16:03:03 2006
<LI><A HREF="#toc63">Prefix-dependent choices</A>
<LI><A HREF="#toc64">Predefined types and operations</A>
</UL>
<LI><A HREF="#toc65">More features of the module system</A>
<LI><A HREF="#toc65">More concepts of abstract syntax</A>
<UL>
<LI><A HREF="#toc66">Interfaces, instances, and functors</A>
<LI><A HREF="#toc67">Resource grammars and their reuse</A>
<LI><A HREF="#toc68">Restricted inheritance and qualified opening</A>
<LI><A HREF="#toc66">GF as a logical framework</A>
<LI><A HREF="#toc67">Dependent types</A>
<LI><A HREF="#toc68">Higher-order abstract syntax</A>
<LI><A HREF="#toc69">Semantic definitions</A>
<LI><A HREF="#toc70">List categories</A>
</UL>
<LI><A HREF="#toc69">More concepts of abstract syntax</A>
<LI><A HREF="#toc71">More features of the module system</A>
<UL>
<LI><A HREF="#toc70">Dependent types</A>
<LI><A HREF="#toc71">Higher-order abstract syntax</A>
<LI><A HREF="#toc72">Semantic definitions</A>
<LI><A HREF="#toc73">List categories</A>
<LI><A HREF="#toc72">Interfaces, instances, and functors</A>
<LI><A HREF="#toc73">Resource grammars and their reuse</A>
<LI><A HREF="#toc74">Restricted inheritance and qualified opening</A>
</UL>
<LI><A HREF="#toc74">Transfer modules</A>
<LI><A HREF="#toc75">Practical issues</A>
<LI><A HREF="#toc75">Using the standard resource library</A>
<UL>
<LI><A HREF="#toc76">Lexers and unlexers</A>
<LI><A HREF="#toc77">Efficiency of grammars</A>
<LI><A HREF="#toc78">Speech input and output</A>
<LI><A HREF="#toc79">Multilingual syntax editor</A>
<LI><A HREF="#toc80">Interactive Development Environment (IDE)</A>
<LI><A HREF="#toc81">Communicating with GF</A>
<LI><A HREF="#toc82">Embedded grammars in Haskell, Java, and Prolog</A>
<LI><A HREF="#toc83">Alternative input and output grammar formats</A>
<LI><A HREF="#toc76">The simplest way</A>
<LI><A HREF="#toc77">How to find resource functions</A>
<LI><A HREF="#toc78">A functor implementation</A>
</UL>
<LI><A HREF="#toc84">Case studies</A>
<LI><A HREF="#toc79">Transfer modules</A>
<LI><A HREF="#toc80">Practical issues</A>
<UL>
<LI><A HREF="#toc85">Interfacing formal and natural languages</A>
<LI><A HREF="#toc81">Lexers and unlexers</A>
<LI><A HREF="#toc82">Efficiency of grammars</A>
<LI><A HREF="#toc83">Speech input and output</A>
<LI><A HREF="#toc84">Multilingual syntax editor</A>
<LI><A HREF="#toc85">Interactive Development Environment (IDE)</A>
<LI><A HREF="#toc86">Communicating with GF</A>
<LI><A HREF="#toc87">Embedded grammars in Haskell, Java, and Prolog</A>
<LI><A HREF="#toc88">Alternative input and output grammar formats</A>
</UL>
<LI><A HREF="#toc89">Case studies</A>
<UL>
<LI><A HREF="#toc90">Interfacing formal and natural languages</A>
</UL>
</UL>
@@ -222,7 +229,8 @@ These grammars can be used as <B>libraries</B> to define application grammars.
In this way, it is possible to write a high-quality grammar without
knowing about linguistics: in general, to write an application grammar
by using the resource library just requires practical knowledge of
the target language.
the target language. and all theoretical knowledge about its grammar
is given by the libraries.
</P>
<A NAME="toc4"></A>
<H3>Who is this tutorial for</H3>
@@ -258,9 +266,10 @@ notation (also known as BNF). The BNF format is often a good
starting point for GF grammar development, because it is
simple and widely used. However, the BNF format is not
good for multilingual grammars. While it is possible to
translate the words contained in a BNF grammar to another
language, proper translation usually involves more, e.g.
changing the word order in
"translate" by just changing the words contained in a
BNF grammar to words of some other
language, proper translation usually involves more.
For instance, the order of words may have to be changed:
</P>
<PRE>
Italian cheese ===&gt; formaggio italiano
@@ -279,14 +288,14 @@ Italian adjectives usually have four forms where English
has just one:
</P>
<PRE>
delicious (wine | wines | pizza | pizzas)
delicious (wine, wines, pizza, pizzas)
vino delizioso, vini deliziosi, pizza deliziosa, pizze deliziose
</PRE>
<P>
The <B>morphology</B> of a language describes the
forms of its words. While the complete description of morphology
belongs to resource grammars, the tutorial will explain the
main programming concepts involved. This will moreover
belongs to resource grammars, this tutorial will explain the
programming concepts involved in morphology. This will moreover
make it possible to grow the fragment covered by the food example.
The tutorial will in fact build a toy resource grammar in order
to illustrate the module structure of library-based application
@@ -584,7 +593,7 @@ a sentence but a sequence of ten sentences.
<H3>Labelled context-free grammars</H3>
<P>
The syntax trees returned by GF's parser in the previous examples
are not so nice to look at. The identifiers of form <CODE>Mks</CODE>
are not so nice to look at. The identifiers that form the tree
are <B>labels</B> of the BNF rules. To see which label corresponds to
which rule, you can use the <CODE>print_grammar = pg</CODE> command
with the <CODE>printer</CODE> flag set to <CODE>cf</CODE> (which means context-free):
@@ -631,7 +640,7 @@ labels to each rule.
In files with the suffix <CODE>.cf</CODE>, you can prefix rules with
labels that you provide yourself - these may be more useful
than the automatically generated ones. The following is a possible
labelling of <CODE>paleolithic.cf</CODE> with nicer-looking labels.
labelling of <CODE>food.cf</CODE> with nicer-looking labels.
</P>
<PRE>
Is. S ::= Item "is" Quality ;
@@ -661,7 +670,7 @@ With this grammar, the trees look as follows:
<IMG ALIGN="middle" SRC="Tree2.png" BORDER="0" ALT="">
</P>
<A NAME="toc17"></A>
<H2>The ``.gf`` grammar format</H2>
<H2>The .gf grammar format</H2>
<P>
To see what there is in GF's shell state when a grammar
has been imported, you can give the plain command
@@ -696,7 +705,7 @@ A GF grammar consists of two main parts:
</UL>
<P>
The EBNF and CF formats fuse these two things together, but it is possible
The CF format fuses these two things together, but it is possible
to take them apart. For instance, the sentence formation rule
</P>
<PRE>
@@ -773,7 +782,7 @@ judgement forms:
<P>
We return to the precise meanings of these judgement forms later.
First we will look at how judgements are grouped into modules, and
show how the paleolithic grammar is
show how the food grammar is
expressed by using modules and judgements.
</P>
<A NAME="toc20"></A>
@@ -950,7 +959,7 @@ A system with this property is called a <B>multilingual grammar</B>.
</P>
<P>
Multilingual grammars can be used for applications such as
translation. Let us buid an Italian concrete syntax for
translation. Let us build an Italian concrete syntax for
<CODE>Food</CODE> and then test the resulting
multilingual grammar.
</P>
@@ -1179,10 +1188,11 @@ The graph uses
<LI>square boxes for concrete modules
<LI>black-headed arrows for inheritance
<LI>white-headed arrows for the concrete-of-abstract relation
<P></P>
<IMG ALIGN="middle" SRC="Foodmarket.png" BORDER="0" ALT="">
</UL>
<P>
<IMG ALIGN="middle" SRC="Foodmarket.png" BORDER="0" ALT="">
</P>
<A NAME="toc34"></A>
<H2>System commands</H2>
<P>
@@ -1203,7 +1213,7 @@ shell escape symbol <CODE>!</CODE>. The resulting graph was shown in the previou
<P>
The command <CODE>print_multi = pm</CODE> is used for printing the current multilingual
grammar in various formats, of which the format <CODE>-printer=graph</CODE> just
shows the module dependencies. Use the <CODE>help</CODE> to see what other formats
shows the module dependencies. Use <CODE>help</CODE> to see what other formats
are available:
</P>
<PRE>
@@ -1216,9 +1226,9 @@ are available:
<A NAME="toc36"></A>
<H3>The golden rule of functional programming</H3>
<P>
In comparison to the <CODE>.cf</CODE> format, the <CODE>.gf</CODE> format still looks rather
In comparison to the <CODE>.cf</CODE> format, the <CODE>.gf</CODE> format looks rather
verbose, and demands lots more characters to be written. You have probably
done this by the copy-paste-modify method, which is a standard way to
done this by the copy-paste-modify method, which is a common way to
avoid repeating work.
</P>
<P>
@@ -1232,8 +1242,8 @@ method. The <B>golden rule of functional programming</B> says that
<P>
A function separates the shared parts of different computations from the
changing parts, parameters. In functional programming languages, such as
<A HREF="http://www.haskell.org">Haskell</A>, it is possible to share muc more than in
the languages such as C and Java.
<A HREF="http://www.haskell.org">Haskell</A>, it is possible to share much more than in
languages such as C and Java.
</P>
<A NAME="toc37"></A>
<H3>Operation definitions</H3>
@@ -1283,11 +1293,8 @@ strings and records.
resource StringOper = {
oper
SS : Type = {s : Str} ;
ss : Str -&gt; SS = \x -&gt; {s = x} ;
cc : SS -&gt; SS -&gt; SS = \x,y -&gt; ss (x.s ++ y.s) ;
prefix : Str -&gt; SS -&gt; SS = \p,x -&gt; ss (p ++ x.s) ;
}
</PRE>
@@ -1433,7 +1440,7 @@ forms of a word are formed.
</P>
<P>
From GF point of view, a paradigm is a function that takes a <B>lemma</B> -
a string also known as a <B>dictionary form</B> - and returns an inflection
also known as a <B>dictionary form</B> - and returns an inflection
table of desired type. Paradigms are not functions in the sense of the
<CODE>fun</CODE> judgements of abstract syntax (which operate on trees and not
on strings), but operations defined in <CODE>oper</CODE> judgements.
@@ -1457,13 +1464,13 @@ are written together to form one <B>token</B>. Thus, for instance,
</PRE>
<P></P>
<A NAME="toc44"></A>
<H3>Worst-case macros and data abstraction</H3>
<H3>Worst-case functions and data abstraction</H3>
<P>
Some English nouns, such as <CODE>mouse</CODE>, are so irregular that
it makes no sense to see them as instances of a paradigm. Even
then, it is useful to perform <B>data abstraction</B> from the
definition of the type <CODE>Noun</CODE>, and introduce a constructor
operation, a <B>worst-case macro</B> for nouns:
operation, a <B>worst-case function</B> for nouns:
</P>
<PRE>
oper mkNoun : Str -&gt; Str -&gt; Noun = \x,y -&gt; {
@@ -1490,7 +1497,7 @@ and
instead of writing the inflection table explicitly.
</P>
<P>
The grammar engineering advantage of worst-case macros is that
The grammar engineering advantage of worst-case functions is that
the author of the resource module may change the definitions of
<CODE>Noun</CODE> and <CODE>mkNoun</CODE>, and still retain the
interface (i.e. the system of type signatures) that makes it
@@ -1498,7 +1505,7 @@ correct to use these functions in concrete modules. In programming
terms, <CODE>Noun</CODE> is then treated as an <B>abstract datatype</B>.
</P>
<A NAME="toc45"></A>
<H3>A system of paradigms using ``Prelude`` operations</H3>
<H3>A system of paradigms using Prelude operations</H3>
<P>
In addition to the completely regular noun paradigm <CODE>regNoun</CODE>,
some other frequent noun paradigms deserve to be
@@ -1707,7 +1714,7 @@ The rule of subject-verb agreement in English says that the verb
phrase must be inflected in the number of the subject. This
means that a noun phrase (functioning as a subject), inherently
<I>has</I> a number, which it passes to the verb. The verb does not
<I>have</I> a number, but must be able to receive whatever number the
<I>have</I> a number, but must be able to <I>receive</I> whatever number the
subject has. This distinction is nicely represented by the
different linearization types of <B>noun phrases</B> and <B>verb phrases</B>:
</P>
@@ -1717,7 +1724,8 @@ different linearization types of <B>noun phrases</B> and <B>verb phrases</B>:
</PRE>
<P>
We say that the number of <CODE>NP</CODE> is an <B>inherent feature</B>,
whereas the number of <CODE>NP</CODE> is <B>parametric</B>.
whereas the number of <CODE>NP</CODE> is a <B>variable feature</B> (or a
<B>parametric feature</B>).
</P>
<P>
The agreement rule itself is expressed in the linearization rule of
@@ -1823,7 +1831,7 @@ Here is an example of pattern matching, the paradigm of regular adjectives.
}
</PRE>
<P>
A constructor can have patterns as arguments. For instance,
A constructor can be used as a pattern that has patterns as arguments. For instance,
the adjectival paradigm in which the two singular forms are the same,
can be defined
</P>
@@ -1837,9 +1845,9 @@ can be defined
<A NAME="toc54"></A>
<H3>Morphological analysis and morphology quiz</H3>
<P>
Even though in GF morphology
is mostly seen as an auxiliary of syntax, a morphology once defined
can be used on its own right. The command <CODE>morpho_analyse = ma</CODE>
Even though morphology is in GF
mostly used as an auxiliary for syntax, it
can also be useful on its own right. The command <CODE>morpho_analyse = ma</CODE>
can be used to read a text and return for each word the analyses that
it has in the current concrete syntax.
</P>
@@ -1865,11 +1873,12 @@ the category is set to be something else than <CODE>S</CODE>. For instance,
Score 0/1
</PRE>
<P>
Finally, a list of morphological exercises and save it in a
Finally, a list of morphological exercises can be generated
off-line saved in a
file for later use, by the command <CODE>morpho_list = ml</CODE>
</P>
<PRE>
&gt; morpho_list -number=25 -cat=V
&gt; morpho_list -number=25 -cat=V | wf exx.txt
</PRE>
<P>
The <CODE>number</CODE> flag gives the number of exercises generated.
@@ -1884,25 +1893,36 @@ a sentence may place the object between the verb and the particle:
<I>he switched it off</I>.
</P>
<P>
The first of the following judgements defines transitive verbs as
The following judgement defines transitive verbs as
<B>discontinuous constituents</B>, i.e. as having a linearization
type with two strings and not just one. The second judgement
type with two strings and not just one.
</P>
<PRE>
lincat TV = {s : Number =&gt; Str ; part : Str} ;
</PRE>
<P>
This linearization rule
shows how the constituents are separated by the object in complementization.
</P>
<PRE>
lincat TV = {s : Number =&gt; Str ; part : Str} ;
lin PredTV tv obj = {s = \\n =&gt; tv.s ! n ++ obj.s ++ tv.part} ;
</PRE>
<P>
There is no restriction in the number of discontinuous constituents
(or other fields) a <CODE>lincat</CODE> may contain. The only condition is that
the fields must be of finite types, i.e. built from records, tables,
parameters, and <CODE>Str</CODE>, and not functions. A mathematical result
parameters, and <CODE>Str</CODE>, and not functions.
</P>
<P>
A mathematical result
about parsing in GF says that the worst-case complexity of parsing
increases with the number of discontinuous constituents. Moreover,
the parsing and linearization commands only give reliable results
for categories whose linearization type has a unique <CODE>Str</CODE> valued
field labelled <CODE>s</CODE>.
increases with the number of discontinuous constituents. This is
potentially a reason to avoid discontinuous constituents.
Moreover, the parsing and linearization commands only give accurate
results for categories whose linearization type has a unique <CODE>Str</CODE>
valued field labelled <CODE>s</CODE>. Therefore, discontinuous constituents
are not a good idea in top-level categories accessed by the users
of a grammar application.
</P>
<A NAME="toc56"></A>
<H2>More constructs for concrete syntax</H2>
@@ -1953,8 +1973,25 @@ can be used e.g. if a word lacks a certain form.
In general, <CODE>variants</CODE> should be used cautiously. It is not
recommended for modules aimed to be libraries, because the
user of the library has no way to choose among the variants.
Moreover, even though <CODE>variants</CODE> admits lists of any type,
its semantics for complex types can cause surprises.
Moreover, <CODE>variants</CODE> is only defined for basic types (<CODE>Str</CODE>
and parameter types). The grammar compiler will admit
<CODE>variants</CODE> for any types, but it will push it to the
level of basic types in a way that may be unwanted.
For instance, German has two words meaning "car",
<I>Wagen</I>, which is Masculine, and <I>Auto</I>, which is Neuter.
However, if one writes
</P>
<PRE>
variants {{s = "Wagen" ; g = Masc} ; {s = "Auto" ; g = Neutr}}
</PRE>
<P>
this will compute to
</P>
<PRE>
{s = variants {"Wagen" ; "Auto"} ; g = variants {Masc ; Neutr}}
</PRE>
<P>
which will also accept erroneous combinations of strings and genders.
</P>
<A NAME="toc59"></A>
<H3>Record extension and subtyping</H3>
@@ -2039,9 +2076,6 @@ possible to write, slightly surprisingly,
<A NAME="toc62"></A>
<H3>Regular expression patterns</H3>
<P>
(New since 7 January 2006.)
</P>
<P>
To define string operations computed at compile time, such
as in morphology, it is handy to use regular expression patterns:
</P>
@@ -2076,7 +2110,6 @@ Another example: English noun plural formation.
x + "y" =&gt; x + "ies" ;
_ =&gt; w + "s"
} ;
</PRE>
<P>
Semantics: variables are always bound to the <B>first match</B>, which is the first
@@ -2085,8 +2118,10 @@ in the sequence of binding lists <CODE>Match p v</CODE> defined as follows. In t
</P>
<PRE>
Match (p1|p2) v = Match p1 v ++ Match p2 v
Match (p1+p2) s = [Match p1 s1 ++ Match p2 s2 | i &lt;- [0..length s], (s1,s2) = splitAt i s]
Match p* s = Match "" s ++ Match p s ++ Match (p + p) s ++ ...
Match (p1+p2) s = [Match p1 s1 ++ Match p2 s2 |
i &lt;- [0..length s], (s1,s2) = splitAt i s]
Match p* s = [[]] if Match "" s ++ Match p s ++ Match (p+p) s ++... /= []
Match -p v = [[]] if Match p v = []
Match c v = [[]] if c == v -- for constant and literal patterns c
Match x v = [[(x,v)]] -- for variable patterns x
Match x@p v = [[(x,v)]] + M if M = Match p v /= []
@@ -2097,14 +2132,18 @@ Examples:
</P>
<UL>
<LI><CODE>x + "e" + y</CODE> matches <CODE>"peter"</CODE> with <CODE>x = "p", y = "ter"</CODE>
<LI><CODE>x@("foo"*)</CODE> matches any token with <CODE>x = ""</CODE>
<LI><CODE>x + y@("er"*)</CODE> matches <CODE>"burgerer"</CODE> with <CODE>x = "burg", y = "erer"</CODE>
<LI><CODE>x + "er"*</CODE> matches <CODE>"burgerer"</CODE> with ``x = "burg"
</UL>
<A NAME="toc63"></A>
<H3>Prefix-dependent choices</H3>
<P>
The construct exemplified in
Sometimes a token has different forms depending on the token
that follows. An example is the English indefinite article,
which is <I>an</I> if a vowel follows, <I>a</I> otherwise.
Which form is chosen can only be decided at run time, i.e.
when a string is actually build. GF has a special construct for
such tokens, the <CODE>pre</CODE> construct exemplified in
</P>
<PRE>
oper artIndef : Str =
@@ -2152,22 +2191,61 @@ they can be used as arguments. For example:
-- e.g. (StreetAddress 10 "Downing Street") : Address
</PRE>
<P></P>
<P>
The linearization type is <CODE>{s : Str}</CODE> for all these categories.
</P>
<A NAME="toc65"></A>
<H2>More features of the module system</H2>
<H2>More concepts of abstract syntax</H2>
<A NAME="toc66"></A>
<H3>Interfaces, instances, and functors</H3>
<H3>GF as a logical framework</H3>
<P>
In this section, we will show how
to encode advanced semantic concepts in an abstract syntax.
We use concepts inherited from <B>type theory</B>. Type theory
is the basis of many systems known as <B>logical frameworks</B>, which are
used for representing mathematical theorems and their proofs on a computer.
In fact, GF has a logical framework as its proper part:
this part is the abstract syntax.
</P>
<P>
In a logical framework, the formalization of a mathematical theory
is a set of type and function declarations. The following is an example
of such a theory, represented as an <CODE>abstract</CODE> module in GF.
</P>
<PRE>
abstract Geometry = {
cat
Line ; Point ; Circle ; -- basic types of figures
Prop ; -- proposition
fun
Parallel : Line -&gt; Line -&gt; Prop ; -- x is parallel to y
Centre : Circle -&gt; Point ; -- the centre of c
}
</PRE>
<P></P>
<A NAME="toc67"></A>
<H3>Dependent types</H3>
<A NAME="toc68"></A>
<H3>Higher-order abstract syntax</H3>
<A NAME="toc69"></A>
<H3>Semantic definitions</H3>
<A NAME="toc70"></A>
<H3>List categories</H3>
<A NAME="toc71"></A>
<H2>More features of the module system</H2>
<A NAME="toc72"></A>
<H3>Interfaces, instances, and functors</H3>
<A NAME="toc73"></A>
<H3>Resource grammars and their reuse</H3>
<P>
A resource grammar is a grammar built on linguistic grounds,
to describe a language rather than a domain.
The GF resource grammar library contains resource grammars for
The GF resource grammar library, which contains resource grammars for
10 languages, is described more closely in the following
documents:
</P>
<UL>
<LI><A HREF="../../lib/resource/doc/gf-resource.html">Resource library API documentation</A>:
<LI><A HREF="../../lib/resource-1.0/doc/">Resource library API documentation</A>:
for application grammarians using the resource.
<LI><A HREF="../../lib/resource-1.0/doc/Resource-HOWTO.html">Resource writing HOWTO</A>:
for resource grammarians developing the resource.
@@ -2177,21 +2255,41 @@ documents:
However, to give a flavour of both using and writing resource grammars,
we have created a miniature resource, which resides in the
subdirectory <A HREF="resource"><CODE>resource</CODE></A>. Its API consists of the following
modules:
three modules:
</P>
<UL>
<LI><A HREF="resource/Syntax.gf">Syntax</A>: syntactic structures, language-independent
<LI><A HREF="resource/LexEng.gf">LexEng</A>: lexical paradigms, English
<LI><A HREF="resource/LexIta.gf">LexIta</A>: lexical paradigms, Italian
</UL>
<P>
<A HREF="resource/Syntax.gf">Syntax</A> - syntactic structures, language-independent:
</P>
<PRE>
</PRE>
<P>
<A HREF="resource/LexEng.gf">LexEng</A> - lexical paradigms, English:
</P>
<PRE>
</PRE>
<P>
<A HREF="resource/LexIta.gf">LexIta</A> - lexical paradigms, Italian:
</P>
<PRE>
</PRE>
<P></P>
<P>
Only these three modules should be <CODE>open</CODE>ed in applications.
The implementations of the resource are given in the following four modules:
</P>
<P>
<A HREF="resource/MorphoEng.gf">MorphoEng</A>,
</P>
<PRE>
</PRE>
<P>
<A HREF="resource/MorphoIta.gf">MorphoIta</A>: low-level morphology
</P>
<UL>
<LI><A HREF="resource/MorphoEng.gf">MorphoEng</A>,
<A HREF="resource/MorphoIta.gf">MorphoIta</A>: low-level morphology
<LI><A HREF="resource/SyntaxEng.gf">SyntaxEng</A>.
<A HREF="resource/SyntaxIta.gf">SyntaxIta</A>: definitions of syntactic structures
</UL>
@@ -2210,19 +2308,181 @@ The rest of the modules (black) come from the resource.
<P>
<IMG ALIGN="middle" SRC="Multi.png" BORDER="0" ALT="">
</P>
<A NAME="toc68"></A>
<H3>Restricted inheritance and qualified opening</H3>
<A NAME="toc69"></A>
<H2>More concepts of abstract syntax</H2>
<A NAME="toc70"></A>
<H3>Dependent types</H3>
<A NAME="toc71"></A>
<H3>Higher-order abstract syntax</H3>
<A NAME="toc72"></A>
<H3>Semantic definitions</H3>
<A NAME="toc73"></A>
<H3>List categories</H3>
<A NAME="toc74"></A>
<H3>Restricted inheritance and qualified opening</H3>
<A NAME="toc75"></A>
<H2>Using the standard resource library</H2>
<P>
The example files of this chapter can be found in
the directory <A HREF="./arithm"><CODE>arithm</CODE></A>.
</P>
<A NAME="toc76"></A>
<H3>The simplest way</H3>
<P>
The simplest way is to <CODE>open</CODE> a top-level <CODE>Lang</CODE> module
and a <CODE>Paradigms</CODE> module:
</P>
<PRE>
abstract Foo = ...
concrete FooEng = open LangEng, ParadigmsEng in ...
concrete FooSwe = open LangSwe, ParadigmsSwe in ...
</PRE>
<P>
Here is an example.
</P>
<PRE>
abstract Arithm = {
cat
Prop ;
Nat ;
fun
Zero : Nat ;
Succ : Nat -&gt; Nat ;
Even : Nat -&gt; Prop ;
And : Prop -&gt; Prop -&gt; Prop ;
}
--# -path=.:alltenses:prelude
concrete ArithmEng of Arithm = open LangEng, ParadigmsEng in {
lincat
Prop = S ;
Nat = NP ;
lin
Zero =
UsePN (regPN "zero" nonhuman) ;
Succ n =
DetCN (DetSg (SgQuant DefArt) NoOrd) (ComplN2 (regN2 "successor") n) ;
Even n =
UseCl TPres ASimul PPos
(PredVP n (UseComp (CompAP (PositA (regA "even"))))) ;
And x y =
ConjS and_Conj (BaseS x y) ;
}
--# -path=.:alltenses:prelude
concrete ArithmSwe of Arithm = open LangSwe, ParadigmsSwe in {
lincat
Prop = S ;
Nat = NP ;
lin
Zero =
UsePN (regPN "noll" neutrum) ;
Succ n =
DetCN (DetSg (SgQuant DefArt) NoOrd)
(ComplN2 (mkN2 (mk2N "efterföljare" "efterföljare")
(mkPreposition "till")) n) ;
Even n =
UseCl TPres ASimul PPos
(PredVP n (UseComp (CompAP (PositA (regA "jämn"))))) ;
And x y =
ConjS and_Conj (BaseS x y) ;
}
</PRE>
<P></P>
<A NAME="toc77"></A>
<H3>How to find resource functions</H3>
<P>
The definitions in this example were found by parsing:
</P>
<PRE>
&gt; i LangEng.gf
-- for Successor:
&gt; p -cat=NP -mcfg -parser=topdown "the mother of Paris"
-- for Even:
&gt; p -cat=S -mcfg -parser=topdown "Paris is old"
-- for And:
&gt; p -cat=S -mcfg -parser=topdown "Paris is old and I am old"
</PRE>
<P>
The use of parsing can be systematized by <B>example-based grammar writing</B>,
to which we will return later.
</P>
<A NAME="toc78"></A>
<H3>A functor implementation</H3>
<P>
The interesting thing now is that the
code in <CODE>ArithmSwe</CODE> is similar to the code in <CODE>ArithmEng</CODE>, except for
some lexical items ("noll" vs. "zero", "efterföljare" vs. "successor",
"jämn" vs. "even"). How can we exploit the similarities and
actually share code between the languages?
</P>
<P>
The solution is to use a functor: an <CODE>incomplete</CODE> module that opens
an <CODE>abstract</CODE> as an <CODE>interface</CODE>, and then instantiate it to different
languages that implement the interface. The structure is as follows:
</P>
<PRE>
abstract Foo ...
incomplete concrete FooI = open Lang, Lex in ...
concrete FooEng of Foo = FooI with (Lang=LangEng), (Lex=LexEng) ;
concrete FooSwe of Foo = FooI with (Lang=LangSwe), (Lex=LexSwe) ;
</PRE>
<P>
where <CODE>Lex</CODE> is an abstract lexicon that includes the vocabulary
specific to this application:
</P>
<PRE>
abstract Lex = Cat ** ...
concrete LexEng of Lex = CatEng ** open ParadigmsEng in ...
concrete LexSwe of Lex = CatSwe ** open ParadigmsSwe in ...
</PRE>
<P>
Here, again, a complete example (<CODE>abstract Arithm</CODE> is as above):
</P>
<PRE>
incomplete concrete ArithmI of Arithm = open Lang, Lex in {
lincat
Prop = S ;
Nat = NP ;
lin
Zero =
UsePN zero_PN ;
Succ n =
DetCN (DetSg (SgQuant DefArt) NoOrd) (ComplN2 successor_N2 n) ;
Even n =
UseCl TPres ASimul PPos
(PredVP n (UseComp (CompAP (PositA even_A)))) ;
And x y =
ConjS and_Conj (BaseS x y) ;
}
--# -path=.:alltenses:prelude
concrete ArithmEng of Arithm = ArithmI with
(Lang = LangEng),
(Lex = LexEng) ;
--# -path=.:alltenses:prelude
concrete ArithmSwe of Arithm = ArithmI with
(Lang = LangSwe),
(Lex = LexSwe) ;
abstract Lex = Cat ** {
fun
zero_PN : PN ;
successor_N2 : N2 ;
even_A : A ;
}
concrete LexSwe of Lex = CatSwe ** open ParadigmsSwe in {
lin
zero_PN = regPN "noll" neutrum ;
successor_N2 =
mkN2 (mk2N "efterföljare" "efterföljare") (mkPreposition "till") ;
even_A = regA "jämn" ;
}
</PRE>
<P></P>
<A NAME="toc79"></A>
<H2>Transfer modules</H2>
<P>
Transfer means noncompositional tree-transforming operations.
@@ -2241,9 +2501,9 @@ See the
<A HREF="../transfer.html">transfer language documentation</A>
for more information.
</P>
<A NAME="toc75"></A>
<A NAME="toc80"></A>
<H2>Practical issues</H2>
<A NAME="toc76"></A>
<A NAME="toc81"></A>
<H3>Lexers and unlexers</H3>
<P>
Lexers and unlexers can be chosen from
@@ -2279,7 +2539,7 @@ Given by <CODE>help -lexer</CODE>, <CODE>help -unlexer</CODE>:
</PRE>
<P></P>
<A NAME="toc77"></A>
<A NAME="toc82"></A>
<H3>Efficiency of grammars</H3>
<P>
Issues:
@@ -2290,7 +2550,7 @@ Issues:
<LI>parsing efficiency: <CODE>-mcfg</CODE> vs. others
</UL>
<A NAME="toc78"></A>
<A NAME="toc83"></A>
<H3>Speech input and output</H3>
<P>
The<CODE>speak_aloud = sa</CODE> command sends a string to the speech
@@ -2320,7 +2580,7 @@ The method words only for grammars of English.
Both Flite and ATK are freely available through the links
above, but they are not distributed together with GF.
</P>
<A NAME="toc79"></A>
<A NAME="toc84"></A>
<H3>Multilingual syntax editor</H3>
<P>
The
@@ -2337,12 +2597,12 @@ Here is a snapshot of the editor:
The grammars of the snapshot are from the
<A HREF="http://www.cs.chalmers.se/~aarne/GF/examples/letter">Letter grammar package</A>.
</P>
<A NAME="toc80"></A>
<A NAME="toc85"></A>
<H3>Interactive Development Environment (IDE)</H3>
<P>
Forthcoming.
</P>
<A NAME="toc81"></A>
<A NAME="toc86"></A>
<H3>Communicating with GF</H3>
<P>
Other processes can communicate with the GF command interpreter,
@@ -2359,7 +2619,7 @@ Thus the most silent way to invoke GF is
</PRE>
</UL>
<A NAME="toc82"></A>
<A NAME="toc87"></A>
<H3>Embedded grammars in Haskell, Java, and Prolog</H3>
<P>
GF grammars can be used as parts of programs written in the
@@ -2371,15 +2631,15 @@ following languages. The links give more documentation.
<LI><A HREF="http://www.cs.chalmers.se/~peb/software.html">Prolog</A>
</UL>
<A NAME="toc83"></A>
<A NAME="toc88"></A>
<H3>Alternative input and output grammar formats</H3>
<P>
A summary is given in the following chart of GF grammar compiler phases:
<IMG ALIGN="middle" SRC="../gf-compiler.png" BORDER="0" ALT="">
</P>
<A NAME="toc84"></A>
<A NAME="toc89"></A>
<H2>Case studies</H2>
<A NAME="toc85"></A>
<A NAME="toc90"></A>
<H3>Interfacing formal and natural languages</H3>
<P>
<A HREF="http://www.cs.chalmers.se/~krijo/thesis/thesisA4.pdf">Formal and Informal Software Specifications</A>,
@@ -2392,6 +2652,6 @@ English and German.
A simpler example will be explained here.
</P>
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