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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: Fri Dec 16 21:04:37 2005
Last update: Fri Dec 16 22:10:53 2005
</FONT></CENTER>
<P></P>
@@ -18,7 +18,7 @@ Last update: Fri Dec 16 21:04:37 2005
<UL>
<LI><A HREF="#toc2">Getting the GF program</A>
</UL>
<LI><A HREF="#toc3">My first grammar</A>
<LI><A HREF="#toc3">The ``.cf`` grammar format</A>
<UL>
<LI><A HREF="#toc4">Importing grammars and parsing strings</A>
<LI><A HREF="#toc5">Generating trees and strings</A>
@@ -28,25 +28,60 @@ Last update: Fri Dec 16 21:04:37 2005
<LI><A HREF="#toc9">More on pipes; tracing</A>
<LI><A HREF="#toc10">Writing and reading files</A>
<LI><A HREF="#toc11">Labelled context-free grammars</A>
<LI><A HREF="#toc12">The labelled context-free format</A>
</UL>
<LI><A HREF="#toc12">The GF grammar format</A>
<LI><A HREF="#toc13">The ``.gf`` grammar format</A>
<UL>
<LI><A HREF="#toc13">Abstract and concrete syntax</A>
<LI><A HREF="#toc14">Resource modules</A>
<LI><A HREF="#toc15">Opening a ``resource``</A>
<LI><A HREF="#toc14">Abstract and concrete syntax</A>
<LI><A HREF="#toc15">Judgement forms</A>
<LI><A HREF="#toc16">Module types</A>
<LI><A HREF="#toc17">Record types, records, and ``Str``s</A>
<LI><A HREF="#toc18">An abstract syntax example</A>
<LI><A HREF="#toc19">A concrete syntax example</A>
<LI><A HREF="#toc20">Modules and files</A>
</UL>
<LI><A HREF="#toc16">Topics still to be written</A>
<LI><A HREF="#toc21">Multilingual grammars and translation</A>
<UL>
<LI><A HREF="#toc17">Free variation</A>
<LI><A HREF="#toc18">Record extension, tuples</A>
<LI><A HREF="#toc19">Predefined types and operations</A>
<LI><A HREF="#toc20">Lexers and unlexers</A>
<LI><A HREF="#toc21">Grammars of formal languages</A>
<LI><A HREF="#toc22">Resource grammars and their reuse</A>
<LI><A HREF="#toc23">Embedded grammars in Haskell, Java, and Prolog</A>
<LI><A HREF="#toc24">Dependent types, variable bindings, semantic definitions</A>
<LI><A HREF="#toc25">Transfer modules</A>
<LI><A HREF="#toc26">Alternative input and output grammar formats</A>
<LI><A HREF="#toc22">An Italian concrete syntax</A>
<LI><A HREF="#toc23">Using a multilingual grammar</A>
<LI><A HREF="#toc24">Translation quiz</A>
<LI><A HREF="#toc25">The multilingual shell state</A>
</UL>
<LI><A HREF="#toc26">Grammar architecture</A>
<UL>
<LI><A HREF="#toc27">Extending a grammar</A>
<LI><A HREF="#toc28">Multiple inheritance</A>
<LI><A HREF="#toc29">Visualizing module structure</A>
<LI><A HREF="#toc30">The module structure of ``GathererEng``</A>
</UL>
<LI><A HREF="#toc31">Resource modules</A>
<UL>
<LI><A HREF="#toc32">Parameters and tables</A>
<LI><A HREF="#toc33">Inflection tables, paradigms, and ``oper`` definitions</A>
<LI><A HREF="#toc34">The ``resource`` module type</A>
<LI><A HREF="#toc35">Opening a ``resource``</A>
<LI><A HREF="#toc36">Worst-case macros and data abstraction</A>
<LI><A HREF="#toc37">A system of paradigms using ``Prelude`` operations</A>
<LI><A HREF="#toc38">An intelligent noun paradigm using ``case`` expressions</A>
<LI><A HREF="#toc39">Pattern matching</A>
<LI><A HREF="#toc40">Morphological analysis and morphology quiz</A>
<LI><A HREF="#toc41">Parametric vs. inherent features, agreement</A>
<LI><A HREF="#toc42">English concrete syntax with parameters</A>
<LI><A HREF="#toc43">Hierarchic parameter types</A>
<LI><A HREF="#toc44">Discontinuous constituents</A>
</UL>
<LI><A HREF="#toc45">Topics still to be written</A>
<UL>
<LI><A HREF="#toc46">Free variation</A>
<LI><A HREF="#toc47">Record extension, tuples</A>
<LI><A HREF="#toc48">Predefined types and operations</A>
<LI><A HREF="#toc49">Lexers and unlexers</A>
<LI><A HREF="#toc50">Grammars of formal languages</A>
<LI><A HREF="#toc51">Resource grammars and their reuse</A>
<LI><A HREF="#toc52">Embedded grammars in Haskell, Java, and Prolog</A>
<LI><A HREF="#toc53">Dependent types, variable bindings, semantic definitions</A>
<LI><A HREF="#toc54">Transfer modules</A>
<LI><A HREF="#toc55">Alternative input and output grammar formats</A>
</UL>
</UL>
@@ -109,7 +144,7 @@ To start the GF program, assuming you have installed it, just type
in the shell. You will see GF's welcome message and the prompt <CODE>&gt;</CODE>.
</P>
<A NAME="toc3"></A>
<H2>My first grammar</H2>
<H2>The ``.cf`` grammar format</H2>
<P>
Now you are ready to try out your first grammar.
We start with one that is not written in GF language, but
@@ -260,7 +295,7 @@ generate ten strings with one and the same command:
<A NAME="toc8"></A>
<H3>Systematic generation</H3>
<P>
To generate &lt;i&gt;all&lt;i&gt; sentence that a grammar
To generate <I>all</I> sentence that a grammar
can generate, use the command <CODE>generate_trees = gt</CODE>.
</P>
<PRE>
@@ -301,9 +336,10 @@ want to see:
</P>
<PRE>
&gt; gr -tr | l -tr | p
Mks_0 (Mks_7 Mks_10) (Mks_1 Mks_18)
a louse sleeps
Mks_0 (Mks_7 Mks_10) (Mks_1 Mks_18)
S_NP_VP (NP_the_CN CN_snake) (VP_V V_sleeps)
the snake sleeps
S_NP_VP (NP_the_CN CN_snake) (VP_V V_sleeps)
</PRE>
<P>
This facility is good for test purposes: for instance, you
@@ -324,7 +360,7 @@ You can read the file back to GF with the
<CODE>read_file = rf</CODE> command,
</P>
<PRE>
&gt; read_file exx.tmp | l -tr | p -lines
&gt; read_file exx.tmp | p -lines
</PRE>
<P>
Notice the flag <CODE>-lines</CODE> given to the parsing
@@ -338,45 +374,51 @@ a sentence but a sequence of ten sentences.
<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 <B>labels</B> of the EBNF rules. To see which label corresponds to
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):
</P>
<PRE>
&gt; print_grammar -printer=cf
Mks_10. CN ::= "louse" ;
Mks_11. CN ::= "snake" ;
Mks_12. CN ::= "worm" ;
Mks_8. CN ::= A CN ;
Mks_9. CN ::= "boy" ;
Mks_4. NP ::= "this" CN ;
Mks_15. A ::= "thick" ;
V_laughs. V ::= "laughs" ;
V_sleeps. V ::= "sleeps" ;
V_swims. V ::= "swims" ;
VP_TV_NP. VP ::= TV NP ;
VP_V. VP ::= V ;
VP_is_A. VP ::= "is" A ;
TV_eats. TV ::= "eats" ;
TV_kills. TV ::= "kills" ;
TV_washes. TV ::= "washes" ;
S_NP_VP. S ::= NP VP ;
NP_a_CN. NP ::= "a" ;
...
</PRE>
<P>
A syntax tree such as
</P>
<PRE>
Mks_4 (Mks_8 Mks_15 Mks_12)
NP_this_CN (CN_A_CN A_thick CN_worm)
this thick worm
</PRE>
<P>
encodes the sequence of grammar rules used for building the
expression. If you look at this tree, you will notice that <CODE>Mks_4</CODE>
is the label of the rule prefixing <CODE>this</CODE> to a common noun,
<CODE>Mks_15</CODE> is the label of the adjective <CODE>thick</CODE>,
and so on.
</P>
<P>
&lt;h4&gt;The labelled context-free format&lt;h4&gt;
expression. If you look at this tree, you will notice that <CODE>NP_this_CN</CODE>
is the label of the rule prefixing <CODE>this</CODE> to a common noun (<CODE>CN</CODE>),
thereby forming a noun phrase (<CODE>NP</CODE>).
<CODE>A_thick</CODE> is the label of the adjective <CODE>thick</CODE>,
and so on. These labels are formed automatically when the grammar
is compiled by GF.
</P>
<A NAME="toc12"></A>
<H3>The labelled context-free format</H3>
<P>
The <B>labelled context-free grammar</B> format permits user-defined
labels to each rule.
GF recognizes files of this format by the suffix
<CODE>.cf</CODE>. It is intermediate between EBNF and full GF format.
Let us include the following rules in the file
<CODE>paleolithic.cf</CODE>.
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.
</P>
<PRE>
PredVP. S ::= NP VP ;
@@ -403,25 +445,10 @@ Let us include the following rules in the file
Kill. TV ::= "kills"
Wash. TV ::= "washes" ;
</PRE>
<P></P>
<P>
&lt;h4&gt;Using the labelled context-free format&lt;h4&gt;
</P>
<P>
The GF commands for the <CODE>.cf</CODE> format are
exactly the same as for the <CODE>.ebnf</CODE> format.
Just the syntax trees become nicer to read and
to remember. Notice that before reading in
a new grammar in GF you often (but not always,
as we will see later) have first to give the
command (<CODE>empty = e</CODE>), which removes the
old grammar from the GF shell state.
With this grammar, the trees look as follows:
</P>
<PRE>
&gt; empty
&gt; i paleolithic.cf
&gt; p "the boy eats a snake"
PredVP (Def Boy) (ComplTV Eat (Indef Snake))
@@ -430,10 +457,10 @@ old grammar from the GF shell state.
a louse is thick
</PRE>
<P></P>
<A NAME="toc12"></A>
<H2>The GF grammar format</H2>
<A NAME="toc13"></A>
<H2>The ``.gf`` grammar format</H2>
<P>
To see what there really is in GF's shell state when a grammar
To see what there is in GF's shell state when a grammar
has been imported, you can give the plain command
<CODE>print_grammar = pg</CODE>.
</P>
@@ -446,15 +473,16 @@ you did not need to write the grammar in that notation, but that the
GF grammar compiler produced it.
</P>
<P>
However, we will now start to show how GF's own notation gives you
much more expressive power than the <CODE>.cf</CODE> and <CODE>.ebnf</CODE>
formats. We will introduce the <CODE>.gf</CODE> format by presenting
However, we will now start the demonstration
how GF's own notation gives you
much more expressive power than the <CODE>.cf</CODE>
format. We will introduce the <CODE>.gf</CODE> format by presenting
one more way of defining the same grammar as in
<CODE>paleolithic.cf</CODE> and <CODE>paleolithic.ebnf</CODE>.
<CODE>paleolithic.cf</CODE>.
Then we will show how the full GF grammar format enables you
to do things that are not possible in the weaker formats.
</P>
<A NAME="toc13"></A>
<A NAME="toc14"></A>
<H3>Abstract and concrete syntax</H3>
<P>
A GF grammar consists of two main parts:
@@ -482,16 +510,15 @@ is interpreted as the following pair of rules:
The former rule, with the keyword <CODE>fun</CODE>, belongs to the abstract syntax.
It defines the <B>function</B>
<CODE>PredVP</CODE> which constructs syntax trees of form
(<CODE>PredVP</CODE> &lt;i&gt;x&lt;i&gt; &lt;i&gt;y&lt;i&gt;).
(<CODE>PredVP</CODE> <I>x</I> <I>y</I>).
</P>
<P>
The latter rule, with the keyword <CODE>lin</CODE>, belongs to the concrete syntax.
It defines the <B>linearization function</B> for
syntax trees of form (<CODE>PredVP</CODE> &lt;i&gt;x&lt;i&gt; &lt;i&gt;y&lt;i&gt;).
</P>
<P>
&lt;h4&gt;Judgement forms&lt;h4&gt;
syntax trees of form (<CODE>PredVP</CODE> <I>x</I> <I>y</I>).
</P>
<A NAME="toc15"></A>
<H3>Judgement forms</H3>
<P>
Rules in a GF grammar are called <B>judgements</B>, and the keywords
<CODE>fun</CODE> and <CODE>lin</CODE> are used for distinguishing between two
@@ -543,27 +570,25 @@ 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 grammar <CODE>paleolithic.cf</CODE> is
show how the paleolithic grammar is
expressed by using modules and judgements.
</P>
<P>
&lt;h4&gt;Module types&lt;h4&gt;
</P>
<A NAME="toc16"></A>
<H3>Module types</H3>
<P>
A GF grammar consists of <B>modules</B>,
into which judgements are grouped. The most important
module forms are
</P>
<UL>
<LI><CODE>abstract</CODE> A = M``, abstract syntax A with judgements in
<LI><CODE>abstract</CODE> A <CODE>=</CODE> M, abstract syntax A with judgements in
the module body M.
<LI><CODE>concrete</CODE> C <CODE>of</CODE> A = M``, concrete syntax C of the
<LI><CODE>concrete</CODE> C <CODE>of</CODE> A <CODE>=</CODE> M, concrete syntax C of the
abstract syntax A, with judgements in the module body M.
</UL>
<P>
&lt;h4&gt;Record types, records, and <CODE>Str</CODE>s&lt;h4&gt;
</P>
<A NAME="toc17"></A>
<H3>Record types, records, and ``Str``s</H3>
<P>
The linearization type of a category is a <B>record type</B>, with
zero of more <B>fields</B> of different types. The simplest record
@@ -579,8 +604,8 @@ which has one field, with <B>label</B> <CODE>s</CODE> and type <CODE>Str</CODE>.
Examples of records of this type are
</P>
<PRE>
[s = "foo"}
[s = "hello" ++ "world"}
{s = "foo"}
{s = "hello" ++ "world"}
</PRE>
<P>
The type <CODE>Str</CODE> is really the type of <B>token lists</B>, but
@@ -589,18 +614,26 @@ denoted by string literals in double quotes.
</P>
<P>
Whenever a record <CODE>r</CODE> of type <CODE>{s : Str}</CODE> is given,
<CODE>r.s</CODE> is an object of type <CODE>Str</CODE>. This is of course
<CODE>r.s</CODE> is an object of type <CODE>Str</CODE>. This is
a special case of the <B>projection</B> rule, allowing the extraction
of fields from a record.
of fields from a record:
</P>
<UL>
<LI>if <I>r</I> : <CODE>{</CODE> ... <I>p</I> : <I>T</I> ... <CODE>}</CODE> then <I>r.p</I> : <I>T</I>
</UL>
<A NAME="toc18"></A>
<H3>An abstract syntax example</H3>
<P>
&lt;h4&gt;An abstract syntax example&lt;h4&gt;
</P>
<P>
Each nonterminal occurring in the grammar <CODE>paleolithic.cf</CODE> is
introduced by a <CODE>cat</CODE> judgement. Each
rule label is introduced by a <CODE>fun</CODE> judgement.
To express the abstract syntax of <CODE>paleolithic.cf</CODE> in
a file <CODE>Paleolithic.gf</CODE>, we write two kinds of judgements:
</P>
<UL>
<LI>Each category is introduced by a <CODE>cat</CODE> judgement.
<LI>Each rule label is introduced by a <CODE>fun</CODE> judgement,
with the type formed from the nonterminals of the rule.
</UL>
<PRE>
abstract Paleolithic = {
cat
@@ -623,9 +656,8 @@ Notice the use of shorthands permitting the sharing of
the keyword in subsequent judgements, and of the type
in subsequent <CODE>fun</CODE> judgements.
</P>
<P>
&lt;h4&gt;A concrete syntax example&lt;h4&gt;
</P>
<A NAME="toc19"></A>
<H3>A concrete syntax example</H3>
<P>
Each category introduced in <CODE>Paleolithic.gf</CODE> is
given a <CODE>lincat</CODE> rule, and each
@@ -663,9 +695,8 @@ apply as in <CODE>abstract</CODE> modules.
}
</PRE>
<P></P>
<P>
&lt;h4&gt;Modules and files&lt;h4&gt;
</P>
<A NAME="toc20"></A>
<H3>Modules and files</H3>
<P>
Module name + <CODE>.gf</CODE> = file name
</P>
@@ -691,9 +722,8 @@ GF source files. When reading a module, GF knows whether
to use an existing <CODE>.gfc</CODE> file or to generate
a new one, by looking at modification times.
</P>
<P>
&lt;h4&gt;Multilingual grammar&lt;h4&gt;
</P>
<A NAME="toc21"></A>
<H2>Multilingual grammars and translation</H2>
<P>
The main advantage of separating abstract from concrete syntax is that
one abstract syntax can be equipped with many concrete syntaxes.
@@ -705,9 +735,8 @@ translation. Let us buid an Italian concrete syntax for
<CODE>Paleolithic</CODE> and then test the resulting
multilingual grammar.
</P>
<P>
&lt;h4&gt;An Italian concrete syntax&lt;h4&gt;
</P>
<A NAME="toc22"></A>
<H3>An Italian concrete syntax</H3>
<PRE>
concrete PaleolithicIta of Paleolithic = {
lincat
@@ -739,9 +768,8 @@ multilingual grammar.
}
</PRE>
<P></P>
<P>
&lt;h4&gt;Using a multilingual grammar&lt;h4&gt;
</P>
<A NAME="toc23"></A>
<H3>Using a multilingual grammar</H3>
<P>
Import without first emptying
</P>
@@ -767,9 +795,8 @@ Translate by using a pipe:
il ragazzo mangia il serpente
</PRE>
<P></P>
<P>
&lt;h4&gt;Translation quiz&lt;h4&gt;
</P>
<A NAME="toc24"></A>
<H3>Translation quiz</H3>
<P>
This is a simple language exercise that can be automatically
generated from a multilingual grammar. The system generates a set of
@@ -802,9 +829,8 @@ file for later use, by the command <CODE>translation_list = tl</CODE>
<P>
The number flag gives the number of sentences generated.
</P>
<P>
&lt;h4&gt;The multilingual shell state&lt;h4&gt;
</P>
<A NAME="toc25"></A>
<H3>The multilingual shell state</H3>
<P>
A GF shell is at any time in a state, which
contains a multilingual grammar. One of the concrete
@@ -825,9 +851,10 @@ things), you can use the command
all concretes : PaleolithicIta PaleolithicEng
</PRE>
<P></P>
<P>
&lt;h4&gt;Extending a grammar&lt;h4&gt;
</P>
<A NAME="toc26"></A>
<H2>Grammar architecture</H2>
<A NAME="toc27"></A>
<H3>Extending a grammar</H3>
<P>
The module system of GF makes it possible to <B>extend</B> a
grammar in different ways. The syntax of extension is
@@ -856,9 +883,8 @@ be built for concrete syntaxes:
The effect of extension is that all of the contents of the extended
and extending module are put together.
</P>
<P>
&lt;h4&gt;Multiple inheritance&lt;h4&gt;
</P>
<A NAME="toc28"></A>
<H3>Multiple inheritance</H3>
<P>
Specialized vocabularies can be represented as small grammars that
only do "one thing" each, e.g.
@@ -887,9 +913,8 @@ same time:
}
</PRE>
<P></P>
<P>
&lt;h4&gt;Visualizing module structure&lt;h4&gt;
</P>
<A NAME="toc29"></A>
<H3>Visualizing module structure</H3>
<P>
When you have created all the abstract syntaxes and
one set of concrete syntaxes needed for <CODE>Gatherer</CODE>,
@@ -918,9 +943,8 @@ The command <CODE>print_multi = pm</CODE> is used for printing the current multi
grammar in various formats, of which the format <CODE>-printer=graph</CODE> just
shows the module dependencies.
</P>
<P>
&lt;h4&gt;The module structure of <CODE>GathererEng</CODE>&lt;h4&gt;
</P>
<A NAME="toc30"></A>
<H3>The module structure of ``GathererEng``</H3>
<P>
The graph uses
</P>
@@ -934,8 +958,8 @@ The graph uses
<P>
&lt;img src="Gatherer.gif"&gt;
</P>
<A NAME="toc14"></A>
<H3>Resource modules</H3>
<A NAME="toc31"></A>
<H2>Resource modules</H2>
<P>
Suppose we want to say, with the vocabulary included in
<CODE>Paleolithic.gf</CODE>, things like
@@ -946,7 +970,7 @@ Suppose we want to say, with the vocabulary included in
</PRE>
<P>
The new grammatical facility we need are the plural forms
of nouns and verbs (&lt;i&gt;boys, sleep&lt;i&gt;), as opposed to their
of nouns and verbs (<I>boys, sleep</I>), as opposed to their
singular forms.
</P>
<P>
@@ -969,9 +993,8 @@ To be able to do all this, we need two new judgement forms,
a new module form, and a generalizarion of linearization types
from strings to more complex types.
</P>
<P>
&lt;h4&gt;Parameters and tables&lt;h4&gt;
</P>
<A NAME="toc32"></A>
<H3>Parameters and tables</H3>
<P>
We define the <B>parameter type</B> of number in Englisn by
using a new form of judgement:
@@ -1011,13 +1034,12 @@ operator <CODE>!</CODE>. For instance,
<P>
is a selection, whose value is <CODE>"boys"</CODE>.
</P>
<P>
&lt;h4&gt;Inflection tables, paradigms, and <CODE>oper</CODE> definitions&lt;h4&gt;
</P>
<A NAME="toc33"></A>
<H3>Inflection tables, paradigms, and ``oper`` definitions</H3>
<P>
All English common nouns are inflected in number, most of them in the
same way: the plural form is formed from the singular form by adding the
ending &lt;i&gt;s&lt;i&gt;. This rule is an example of
ending <I>s</I>. This rule is an example of
a <B>paradigm</B> - a formula telling how the inflection
forms of a word are formed.
</P>
@@ -1046,9 +1068,8 @@ the function, and the <B>glueing</B> operator <CODE>+</CODE> telling that
the string held in the variable <CODE>x</CODE> and the ending <CODE>"s"</CODE>
are written together to form one <B>token</B>.
</P>
<P>
&lt;h4&gt;The <CODE>resource</CODE> module type&lt;h4&gt;
</P>
<A NAME="toc34"></A>
<H3>The ``resource`` module type</H3>
<P>
Parameter and operator definitions do not belong to the abstract syntax.
They can be used when defining concrete syntax - but they are not
@@ -1080,7 +1101,7 @@ Resource modules can extend other resource modules, in the
same way as modules of other types can extend modules of the
same type.
</P>
<A NAME="toc15"></A>
<A NAME="toc35"></A>
<H3>Opening a ``resource``</H3>
<P>
Any number of <CODE>resource</CODE> modules can be
@@ -1114,9 +1135,8 @@ available through resource grammars, whose users only need
to pick the right operations and not to know their implementation
details.
</P>
<P>
&lt;h4&gt;Worst-case macros and data abstraction&lt;h4&gt;
</P>
<A NAME="toc36"></A>
<H3>Worst-case macros and data abstraction</H3>
<P>
Some English nouns, such as <CODE>louse</CODE>, are so irregular that
it makes little sense to see them as instances of a paradigm. Even
@@ -1149,9 +1169,8 @@ interface (i.e. the system of type signatures) that makes it
correct to use these functions in concrete modules. In programming
terms, <CODE>Noun</CODE> is then treated as an <B>abstract datatype</B>.
</P>
<P>
&lt;h4&gt;A system of paradigms using <CODE>Prelude</CODE> operations&lt;h4&gt;
</P>
<A NAME="toc37"></A>
<H3>A system of paradigms using ``Prelude`` operations</H3>
<P>
The regular noun paradigm <CODE>regNoun</CODE> can - and should - of course be defined
by the worst-case macro <CODE>mkNoun</CODE>. In addition, some more noun paradigms
@@ -1162,8 +1181,8 @@ could be defined, for instance,
sNoun : Str -&gt; Noun = \kiss -&gt; mkNoun kiss (kiss + "es") ;
</PRE>
<P>
What about nouns like &lt;i&gt;fly&lt;i&gt;, with the plural &lt;i&gt;flies&lt;i&gt;? The already
available solution is to use the so-called "technical stem" &lt;i&gt;fl&lt;i&gt; as
What about nouns like <I>fly</I>, with the plural <I>flies</I>? The already
available solution is to use the so-called "technical stem" <I>fl</I> as
argument, and define
</P>
<PRE>
@@ -1183,9 +1202,8 @@ The operator <CODE>init</CODE> belongs to a set of operations in the
resource module <CODE>Prelude</CODE>, which therefore has to be
<CODE>open</CODE>ed so that <CODE>init</CODE> can be used.
</P>
<P>
&lt;h4&gt;An intelligent noun paradigm using <CODE>case</CODE> expressions&lt;h4&gt;
</P>
<A NAME="toc38"></A>
<H3>An intelligent noun paradigm using ``case`` expressions</H3>
<P>
It may be hard for the user of a resource morphology to pick the right
inflection paradigm. A way to help this is to define a more intelligent
@@ -1207,16 +1225,15 @@ these forms are explained in the following section.
</P>
<P>
The paradigms <CODE>regNoun</CODE> does not give the correct forms for
all nouns. For instance, &lt;i&gt;louse - lice&lt;i&gt; and
&lt;i&gt;fish - fish&lt;i&gt; must be given by using <CODE>mkNoun</CODE>.
Also the word &lt;i&gt;boy&lt;i&gt; would be inflected incorrectly; to prevent
all nouns. For instance, <I>louse - lice</I> and
<I>fish - fish</I> must be given by using <CODE>mkNoun</CODE>.
Also the word <I>boy</I> would be inflected incorrectly; to prevent
this, either use <CODE>mkNoun</CODE> or modify
<CODE>regNoun</CODE> so that the <CODE>"y"</CODE> case does not
apply if the second-last character is a vowel.
</P>
<P>
&lt;h4&gt;Pattern matching&lt;h4&gt;
</P>
<A NAME="toc39"></A>
<H3>Pattern matching</H3>
<P>
Expressions of the <CODE>table</CODE> form are built from lists of
argument-value pairs. These pairs are called the <B>branches</B>
@@ -1251,9 +1268,8 @@ programming languages are syntactic sugar for table selections:
case e of {...} === table {...} ! e
</PRE>
<P></P>
<P>
&lt;h4&gt;Morphological analysis and morphology quiz&lt;h4&gt;
</P>
<A NAME="toc40"></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
@@ -1292,14 +1308,13 @@ file for later use, by the command <CODE>morpho_list = ml</CODE>
<P>
The number flag gives the number of exercises generated.
</P>
<P>
&lt;h4&gt;Parametric vs. inherent features, agreement&lt;h4&gt;
</P>
<A NAME="toc41"></A>
<H3>Parametric vs. inherent features, agreement</H3>
<P>
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), in some sense
&lt;i&gt;has&lt;i&gt; a number, which it "sends" to the verb. The verb does not
<I>has</I> a number, which it "sends" to the verb. The verb does not
have a number, but must be able to receive whatever number the
subject has. This distinction is nicely represented by the
different linearization types of noun phrases and verb phrases:
@@ -1329,9 +1344,8 @@ regular only in the present tensse).
The reader is invited to inspect the way in which agreement works in
the formation of noun phrases and verb phrases.
</P>
<P>
&lt;h4&gt;English concrete syntax with parameters&lt;h4&gt;
</P>
<A NAME="toc42"></A>
<H3>English concrete syntax with parameters</H3>
<PRE>
concrete PaleolithicEng of Paleolithic = open MorphoEng in {
lincat
@@ -1358,9 +1372,8 @@ the formation of noun phrases and verb phrases.
}
</PRE>
<P></P>
<P>
&lt;h4&gt;Hierarchic parameter types&lt;h4&gt;
</P>
<A NAME="toc43"></A>
<H3>Hierarchic parameter types</H3>
<P>
The reader familiar with a functional programming language such as
&lt;a href="<A HREF="http://www.haskell.org">http://www.haskell.org</A>"&gt;Haskell&lt;a&gt; must have noticed the similarity
@@ -1401,15 +1414,14 @@ the adjectival paradigm in which the two singular forms are the same, can be def
}
</PRE>
<P></P>
<P>
&lt;h4&gt;Discontinuous constituents&lt;h4&gt;
</P>
<A NAME="toc44"></A>
<H3>Discontinuous constituents</H3>
<P>
A linearization type may contain more strings than one.
An example of where this is useful are English particle
verbs, such as &lt;i&gt;switch off&lt;i&gt;. The linearization of
verbs, such as <I>switch off</I>. The linearization of
a sentence may place the object between the verb and the particle:
&lt;i&gt;he switched it off&lt;i&gt;.
<I>he switched it off</I>.
</P>
<P>
The first of the following judgements defines transitive verbs as a
@@ -1427,27 +1439,27 @@ GF currently requires that all fields in linearization records that
have a table with value type <CODE>Str</CODE> have as labels
either <CODE>s</CODE> or <CODE>s</CODE> with an integer index.
</P>
<A NAME="toc16"></A>
<A NAME="toc45"></A>
<H2>Topics still to be written</H2>
<A NAME="toc17"></A>
<A NAME="toc46"></A>
<H3>Free variation</H3>
<A NAME="toc18"></A>
<A NAME="toc47"></A>
<H3>Record extension, tuples</H3>
<A NAME="toc19"></A>
<A NAME="toc48"></A>
<H3>Predefined types and operations</H3>
<A NAME="toc20"></A>
<A NAME="toc49"></A>
<H3>Lexers and unlexers</H3>
<A NAME="toc21"></A>
<A NAME="toc50"></A>
<H3>Grammars of formal languages</H3>
<A NAME="toc22"></A>
<A NAME="toc51"></A>
<H3>Resource grammars and their reuse</H3>
<A NAME="toc23"></A>
<A NAME="toc52"></A>
<H3>Embedded grammars in Haskell, Java, and Prolog</H3>
<A NAME="toc24"></A>
<A NAME="toc53"></A>
<H3>Dependent types, variable bindings, semantic definitions</H3>
<A NAME="toc25"></A>
<A NAME="toc54"></A>
<H3>Transfer modules</H3>
<A NAME="toc26"></A>
<A NAME="toc55"></A>
<H3>Alternative input and output grammar formats</H3>
<!-- html code generated by txt2tags 2.3 (http://txt2tags.sf.net) -->

125
doc/tutorial/gf-tutorial2.txt
View File

@@ -66,7 +66,7 @@ in the shell. You will see GF's welcome message and the prompt ``>``.
%--!
==My first grammar==
==The ``.cf`` grammar format==
Now you are ready to try out your first grammar.
We start with one that is not written in GF language, but
@@ -200,7 +200,7 @@ generate ten strings with one and the same command:
%--!
===Systematic generation===
To generate <i>all<i> sentence that a grammar
To generate //all// sentence that a grammar
can generate, use the command ``generate_trees = gt``.
```
> generate_trees | l
@@ -243,7 +243,7 @@ want to see:
S_NP_VP (NP_the_CN CN_snake) (VP_V V_sleeps)
the snake sleeps
S_NP_VP (NP_the_CN CN_snake) (VP_V V_sleeps)
```
This facility is good for test purposes: for instance, you
may want to see if a grammar is **ambiguous**, i.e.
contains strings that can be parsed in more than one way.
@@ -310,7 +310,7 @@ is compiled by GF.
%--!
<h4>The labelled context-free format<h4>
===The labelled context-free format===
The **labelled context-free grammar** format permits user-defined
labels to each rule.
@@ -355,9 +355,9 @@ With this grammar, the trees look as follows:
%--!
==The GF grammar format==
==The ``.gf`` grammar format==
To see what there really is in GF's shell state when a grammar
To see what there is in GF's shell state when a grammar
has been imported, you can give the plain command
``print_grammar = pg``.
```
@@ -402,17 +402,17 @@ is interpreted as the following pair of rules:
The former rule, with the keyword ``fun``, belongs to the abstract syntax.
It defines the **function**
``PredVP`` which constructs syntax trees of form
(``PredVP`` <i>x<i> <i>y<i>).
(``PredVP`` //x// //y//).
The latter rule, with the keyword ``lin``, belongs to the concrete syntax.
It defines the **linearization function** for
syntax trees of form (``PredVP`` <i>x<i> <i>y<i>).
syntax trees of form (``PredVP`` //x// //y//).
%--!
<h4>Judgement forms<h4>
===Judgement forms===
Rules in a GF grammar are called **judgements**, and the keywords
``fun`` and ``lin`` are used for distinguishing between two
@@ -435,26 +435,26 @@ judgement forms:
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 grammar ``paleolithic.cf`` is
show how the paleolithic grammar is
expressed by using modules and judgements.
%--!
<h4>Module types<h4>
===Module types===
A GF grammar consists of **modules**,
into which judgements are grouped. The most important
module forms are
- ``abstract`` A = M``, abstract syntax A with judgements in
- ``abstract`` A ``=`` M, abstract syntax A with judgements in
the module body M.
- ``concrete`` C ``of`` A = M``, concrete syntax C of the
- ``concrete`` C ``of`` A ``=`` M, concrete syntax C of the
abstract syntax A, with judgements in the module body M.
%--!
<h4>Record types, records, and ``Str``s<h4>
===Record types, records, and ``Str``s===
The linearization type of a category is a **record type**, with
zero of more **fields** of different types. The simplest record
@@ -468,8 +468,8 @@ which has one field, with **label** ``s`` and type ``Str``.
Examples of records of this type are
```
[s = "foo"}
[s = "hello" ++ "world"}
{s = "foo"}
{s = "hello" ++ "world"}
```
The type ``Str`` is really the type of **token lists**, but
most of the time one can conveniently think of it as the type of strings,
@@ -478,17 +478,24 @@ denoted by string literals in double quotes.
Whenever a record ``r`` of type ``{s : Str}`` is given,
``r.s`` is an object of type ``Str``. This is of course
``r.s`` is an object of type ``Str``. This is
a special case of the **projection** rule, allowing the extraction
of fields from a record.
of fields from a record:
- if //r// : ``{`` ... //p// : //T// ... ``}`` then //r.p// : //T//
%--!
<h4>An abstract syntax example<h4>
===An abstract syntax example===
To express the abstract syntax of ``paleolithic.cf`` in
a file ``Paleolithic.gf``, we write two kinds of judgements:
- Each category is introduced by a ``cat`` judgement.
- Each rule label is introduced by a ``fun`` judgement,
with the type formed from the nonterminals of the rule.
Each nonterminal occurring in the grammar ``paleolithic.cf`` is
introduced by a ``cat`` judgement. Each
rule label is introduced by a ``fun`` judgement.
```
abstract Paleolithic = {
cat
@@ -512,7 +519,7 @@ in subsequent ``fun`` judgements.
%--!
<h4>A concrete syntax example<h4>
===A concrete syntax example===
Each category introduced in ``Paleolithic.gf`` is
given a ``lincat`` rule, and each
@@ -551,7 +558,7 @@ lin
%--!
<h4>Modules and files<h4>
===Modules and files===
Module name + ``.gf`` = file name
@@ -581,7 +588,7 @@ a new one, by looking at modification times.
%--!
<h4>Multilingual grammar<h4>
==Multilingual grammars and translation==
The main advantage of separating abstract from concrete syntax is that
one abstract syntax can be equipped with many concrete syntaxes.
@@ -598,7 +605,7 @@ multilingual grammar.
%--!
<h4>An Italian concrete syntax<h4>
===An Italian concrete syntax===
```
concrete PaleolithicIta of Paleolithic = {
@@ -632,7 +639,7 @@ lin
```
%--!
<h4>Using a multilingual grammar<h4>
===Using a multilingual grammar===
Import without first emptying
```
@@ -656,7 +663,7 @@ Translate by using a pipe:
%--!
<h4>Translation quiz<h4>
===Translation quiz===
This is a simple language exercise that can be automatically
generated from a multilingual grammar. The system generates a set of
@@ -687,7 +694,7 @@ The number flag gives the number of sentences generated.
%--!
<h4>The multilingual shell state<h4>
===The multilingual shell state===
A GF shell is at any time in a state, which
contains a multilingual grammar. One of the concrete
@@ -710,7 +717,9 @@ things), you can use the command
%--!
<h4>Extending a grammar<h4>
==Grammar architecture==
===Extending a grammar===
The module system of GF makes it possible to **extend** a
grammar in different ways. The syntax of extension is
@@ -738,7 +747,7 @@ and extending module are put together.
%--!
<h4>Multiple inheritance<h4>
===Multiple inheritance===
Specialized vocabularies can be represented as small grammars that
only do "one thing" each, e.g.
@@ -767,7 +776,7 @@ same time:
%--!
<h4>Visualizing module structure<h4>
===Visualizing module structure===
When you have created all the abstract syntaxes and
one set of concrete syntaxes needed for ``Gatherer``,
@@ -795,7 +804,7 @@ shows the module dependencies.
%--!
<h4>The module structure of ``GathererEng``<h4>
===The module structure of ``GathererEng``===
The graph uses
@@ -811,7 +820,7 @@ The graph uses
%--!
===Resource modules===
==Resource modules==
Suppose we want to say, with the vocabulary included in
``Paleolithic.gf``, things like
@@ -820,7 +829,7 @@ Suppose we want to say, with the vocabulary included in
all boys sleep
```
The new grammatical facility we need are the plural forms
of nouns and verbs (<i>boys, sleep<i>), as opposed to their
of nouns and verbs (//boys, sleep//), as opposed to their
singular forms.
@@ -846,7 +855,7 @@ from strings to more complex types.
%--!
<h4>Parameters and tables<h4>
===Parameters and tables===
We define the **parameter type** of number in Englisn by
using a new form of judgement:
@@ -880,11 +889,11 @@ is a selection, whose value is ``"boys"``.
%--!
<h4>Inflection tables, paradigms, and ``oper`` definitions<h4>
===Inflection tables, paradigms, and ``oper`` definitions===
All English common nouns are inflected in number, most of them in the
same way: the plural form is formed from the singular form by adding the
ending <i>s<i>. This rule is an example of
ending //s//. This rule is an example of
a **paradigm** - a formula telling how the inflection
forms of a word are formed.
@@ -914,7 +923,7 @@ are written together to form one **token**.
%--!
<h4>The ``resource`` module type<h4>
===The ``resource`` module type===
Parameter and operator definitions do not belong to the abstract syntax.
They can be used when defining concrete syntax - but they are not
@@ -983,7 +992,7 @@ details.
%--!
<h4>Worst-case macros and data abstraction<h4>
===Worst-case macros and data abstraction===
Some English nouns, such as ``louse``, are so irregular that
it makes little sense to see them as instances of a paradigm. Even
@@ -1016,7 +1025,7 @@ terms, ``Noun`` is then treated as an **abstract datatype**.
%--!
<h4>A system of paradigms using ``Prelude`` operations<h4>
===A system of paradigms using ``Prelude`` operations===
The regular noun paradigm ``regNoun`` can - and should - of course be defined
by the worst-case macro ``mkNoun``. In addition, some more noun paradigms
@@ -1025,8 +1034,8 @@ could be defined, for instance,
regNoun : Str -> Noun = \snake -> mkNoun snake (snake + "s") ;
sNoun : Str -> Noun = \kiss -> mkNoun kiss (kiss + "es") ;
```
What about nouns like <i>fly<i>, with the plural <i>flies<i>? The already
available solution is to use the so-called "technical stem" <i>fl<i> as
What about nouns like //fly//, with the plural //flies//? The already
available solution is to use the so-called "technical stem" //fl// as
argument, and define
```
yNoun : Str -> Noun = \fl -> mkNoun (fl + "y") (fl + "ies") ;
@@ -1045,7 +1054,7 @@ resource module ``Prelude``, which therefore has to be
%--!
<h4>An intelligent noun paradigm using ``case`` expressions<h4>
===An intelligent noun paradigm using ``case`` expressions===
It may be hard for the user of a resource morphology to pick the right
inflection paradigm. A way to help this is to define a more intelligent
@@ -1066,9 +1075,9 @@ these forms are explained in the following section.
The paradigms ``regNoun`` does not give the correct forms for
all nouns. For instance, <i>louse - lice<i> and
<i>fish - fish<i> must be given by using ``mkNoun``.
Also the word <i>boy<i> would be inflected incorrectly; to prevent
all nouns. For instance, //louse - lice// and
//fish - fish// must be given by using ``mkNoun``.
Also the word //boy// would be inflected incorrectly; to prevent
this, either use ``mkNoun`` or modify
``regNoun`` so that the ``"y"`` case does not
apply if the second-last character is a vowel.
@@ -1076,7 +1085,7 @@ apply if the second-last character is a vowel.
%--!
<h4>Pattern matching<h4>
===Pattern matching===
Expressions of the ``table`` form are built from lists of
argument-value pairs. These pairs are called the **branches**
@@ -1111,7 +1120,7 @@ programming languages are syntactic sugar for table selections:
%--!
<h4>Morphological analysis and morphology quiz<h4>
===Morphological analysis and morphology quiz===
Even though in GF morphology
is mostly seen as an auxiliary of syntax, a morphology once defined
@@ -1147,12 +1156,12 @@ The number flag gives the number of exercises generated.
%--!
<h4>Parametric vs. inherent features, agreement<h4>
===Parametric vs. inherent features, agreement===
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), in some sense
<i>has<i> a number, which it "sends" to the verb. The verb does not
//has// a number, which it "sends" to the verb. The verb does not
have a number, but must be able to receive whatever number the
subject has. This distinction is nicely represented by the
different linearization types of noun phrases and verb phrases:
@@ -1182,7 +1191,7 @@ the formation of noun phrases and verb phrases.
%--!
<h4>English concrete syntax with parameters<h4>
===English concrete syntax with parameters===
```
concrete PaleolithicEng of Paleolithic = open MorphoEng in {
@@ -1213,7 +1222,7 @@ lin
%--!
<h4>Hierarchic parameter types<h4>
===Hierarchic parameter types===
The reader familiar with a functional programming language such as
<a href="http://www.haskell.org">Haskell<a> must have noticed the similarity
@@ -1255,13 +1264,13 @@ the adjectival paradigm in which the two singular forms are the same, can be def
%--!
<h4>Discontinuous constituents<h4>
===Discontinuous constituents===
A linearization type may contain more strings than one.
An example of where this is useful are English particle
verbs, such as <i>switch off<i>. The linearization of
verbs, such as //switch off//. The linearization of
a sentence may place the object between the verb and the particle:
<i>he switched it off<i>.
//he switched it off//.
@@ -1311,6 +1320,10 @@ either ``s`` or ``s`` with an integer index.
===Speech input and output===
===Embedded grammars in Haskell, Java, and Prolog===