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Diffstat (limited to 'doc/tutorial/gf-tutorial2.txt')
| -rw-r--r-- | doc/tutorial/gf-tutorial2.txt | 125 |
1 files changed, 69 insertions, 56 deletions
diff --git a/doc/tutorial/gf-tutorial2.txt b/doc/tutorial/gf-tutorial2.txt index 3286cfcc9..68a31bd45 100644 --- a/doc/tutorial/gf-tutorial2.txt +++ b/doc/tutorial/gf-tutorial2.txt @@ -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=== |