From 14defedc653f50d11a52cecba13632688d1ec811 Mon Sep 17 00:00:00 2001 From: aarne Date: Sat, 17 Dec 2005 20:44:20 +0000 Subject: tutorial; mkMorpho bug fix --- doc/tutorial/gf-tutorial2.html | 247 +++++++++++++++++++++++++++++++++-------- 1 file changed, 200 insertions(+), 47 deletions(-) (limited to 'doc/tutorial/gf-tutorial2.html') diff --git a/doc/tutorial/gf-tutorial2.html b/doc/tutorial/gf-tutorial2.html index 9d82a7f3d..9730526e2 100644 --- a/doc/tutorial/gf-tutorial2.html +++ b/doc/tutorial/gf-tutorial2.html @@ -7,7 +7,7 @@

Grammatical Framework Tutorial

Author: Aarne Ranta <aarne (at) cs.chalmers.se>
-Last update: Sat Dec 17 13:32:10 2005 +Last update: Sat Dec 17 21:42:39 2005

@@ -80,20 +80,35 @@ Last update: Sat Dec 17 13:32:10 2005
  • Morphological analysis and morphology quiz
  • Discontinuous constituents -
  • Topics still to be written +
  • More constructs for concrete syntax +
  • More features of the module system + +
  • More concepts of abstract syntax + +
  • Transfer modules +
  • Practical issues + @@ -619,11 +634,7 @@ Examples of records of this type are {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, -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 @@ -634,6 +645,35 @@ of fields from a record:

  • if r : { ... p : T ... } then r.p : T +

    +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, +denoted by string literals in double quotes. +

    +

    +Notice that +

    +
    +   "hello world"
+
    +

    +is not recommended as an expression of type Str. It denotes +a token with a space in it, and will usually +not work with the lexical analysis that precedes parsing. A shorthand +exemplified by +

    +
    +   ["hello world and people"]  === "hello" ++ "world" ++ "and" ++ "people"
+
    +

    +can be used for lists of tokens. The expression +

    +
    +   []
+
    +

    +denotes the empty token list. +

    An abstract syntax example

    @@ -1498,28 +1538,33 @@ the formation of noun phrases and verb phrases.

    English concrete syntax with parameters

    -  concrete PaleolithicEng of Paleolithic = open MorphoEng in {
+  concrete PaleolithicEng of Paleolithic = open Prelude, MorphoEng in {
   lincat 
-    S, A          = {s : Str} ; 
+    S, A          = SS ; 
     VP, CN, V, TV = {s : Number => Str} ; 
     NP            = {s : Str ; n : Number} ; 
   lin
-    PredVP np vp  = {s = np.s ++ vp.s ! np.n} ;
+    PredVP np vp  = ss (np.s ++ vp.s ! np.n) ;
     UseV   v      = v ;
     ComplTV tv np = {s = \\n => tv.s ! n ++ np.s} ;
-    UseA   a   = {s = \\n => case n of {Sg => "is" ; Pl => "are"} ++ a.s} ;
-    This  cn   = {s = "this" ++ cn.s ! Sg } ; 
-    Indef cn   = {s = "a" ++ cn.s ! Sg} ; 
-    All   cn   = {s = "all" ++ cn.s ! Pl} ; 
-    Two   cn   = {s = "two" ++ cn.s ! Pl} ; 
+    UseA a   = {s = \\n => case n of {Sg => "is" ; Pl => "are"} ++ a.s} ;
+    This     = det Sg "this" ;
+    Indef    = det Sg "a" ;
+    All      = det Pl "all" ;
+    Two      = det Pl "two" ;
     ModA  a cn = {s = \\n => a.s ++ cn.s ! n} ;
     Louse  = mkNoun "louse" "lice" ;
     Snake  = regNoun "snake" ;
-    Green  = {s = "green"} ;
-    Warm   = {s = "warm"} ;
+    Green  = ss "green" ;
+    Warm   = ss "warm" ;
     Laugh  = regVerb "laugh" ;
     Sleep  = regVerb "sleep" ;
     Kill   = regVerb "kill" ;
+  oper
+    det : Number -> Str -> Noun -> {s : Str ; n : Number} = \n,d,cn -> {
+      s = d ++ n.s ! n ;
+      n = n
+      } ;
   }

    @@ -1527,19 +1572,19 @@ the formation of noun phrases and verb phrases.

    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 -between parameter types in GF and algebraic datatypes (data definitions +Haskell must have noticed the similarity +between parameter types in GF and algebraic datatypes (data definitions in Haskell). The GF parameter types are actually a special case of algebraic datatypes: the main restriction is that in GF, these types must be finite. -(This restriction makes it possible to invert linearization rules into +(It is this restriction that makes it possible to invert linearization rules into parsing methods.)

    However, finite is not the same thing as enumerated. Even in GF, parameter constructors can take arguments, provided these arguments are from other -parameter types (recursion is forbidden). Such parameter types impose a -hierarchic order among parameters. They are often useful to define -linguistically accurate parameter systems. +parameter types - only recursion is forbidden. Such parameter types impose a +hierarchic order among parameters. They are often needed to define +the linguistically most accurate parameter systems.

    To give an example, Swedish adjectives @@ -1603,7 +1648,7 @@ file for later use, by the command morpho_list = ml > morpho_list -number=25 -cat=V

    -The number flag gives the number of exercises generated. +The number flag gives the number of exercises generated.

    Discontinuous constituents

    @@ -1615,7 +1660,7 @@ a sentence may place the object between the verb and the particle: he switched it off.

    -The first of the following judgements defines transitive verbs as a +The first of the following judgements defines transitive verbs as discontinuous constituents, i.e. as having a linearization type with two strings and not just one. The second judgement shows how the constituents are separated by the object in complementization. @@ -1624,37 +1669,145 @@ shows how the constituents are separated by the object in complementization. lincat TV = {s : Number => Str ; s2 : Str} ; lin ComplTV tv obj = {s = \\n => tv.s ! n ++ obj.s ++ tv.s2} ; -

    -GF currently requires that all fields in linearization records that -have a table with value type Str have as labels -either s or s with an integer index. +There is no restriction in the number of discontinuous constituents +(or other fields) a lincat may contain. The only condition is that +the fields must be of finite types, i.e. built from records, tables, +parameters, and Str, and not functions. 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 Str valued +field labelled s.

    -

    Topics still to be written

    +

    More constructs for concrete syntax

    Free variation

    +

    +Sometimes there are many alternative ways to define a concrete syntax. +For instance, the verb negation in English can be expressed both by +does not and doesn't. In linguistic terms, these expressions +are in free variation. The variants construct of GF can +be used to give a list of strings in free variation. For example, +

    +
    +    NegVerb verb = {s = variants {["does not"] ; "doesn't} ++ verb.s} ;
+
    +

    +An empty variant list +

    +
    +    variants {}
+
    +

    +can be used e.g. if a word lacks a certain form. +

    +

    +In general, variants 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 variants admits lists of any type, +its semantics for complex types can cause surprises. +

    -

    Record extension, tuples

    +

    Record extension and subtyping

    +

    +Record types and records can be extended with new fields. For instance, +in German it is natural to see transitive verbs as verbs with a case. +The symbol ** is used for both constructs. +

    +
    +    lincat TV = Verb ** {c : Case} ;
+  
+    lin Follow = regVerb "folgen" ** {c = Dative} ; 
+
    +

    +To extend a record type or a record with a field whose label it +already has is a type error. +

    +

    +A record type T is a subtype of another one R, if T has +all the fields of R and possibly other fields. For instance, +an extension of a record type is always a subtype of it. +

    +

    +If T is a subtype of R, an object of T can be used whenever +an object of R is required. For instance, a transitive verb can +be used whenever a verb is required. +

    +

    +Contravariance means that a function taking an R as argument +can also be applied to any object of a subtype T. +

    -

    Predefined types and operations

    +

    Tuples and product types

    +

    +Product types and tuples are syntactic sugar for record types and records: +

    +
    +    T1 * ... * Tn   ===   {p1 : T1 ; ... ; pn : Tn}
+    <t1, ...,  tn>  ===   {p1 = T1 ; ... ; pn = Tn}
+
    +

    +Thus the labels p1, p2,...` are hard-coded. +

    -

    Lexers and unlexers

    +

    Predefined types and operations

    +

    +GF has the following predefined categories in abstract syntax: +

    +
    +    cat Int ;     -- integers, e.g. 0, 5, 743145151019
+    cat Float ;   -- floats, e.g.   0.0, 3.1415926
+    cat String ;  -- strings, e.g.  "", "foo", "123"
+
    +

    +The objects of each of these categories are literals +as indicated in the comments above. No fun definition +can have a predefined category as its value type, but +they can be used as arguments. For example: +

    +
    +    fun StreetAddress : Int -> String -> Address ;
+    lin StreetAddress number street = {s = number.s ++ street.s} ;
+  
+    -- e.g. (StreetAddress 10 "Downing Street") : Address
+
    +

    -

    Grammars of formal languages

    +

    More features of the module system

    Resource grammars and their reuse

    Interfaces, instances, and functors

    -

    Speech input and output

    +

    Restricted inheritance and qualified opening

    -

    Embedded grammars in Haskell, Java, and Prolog

    +

    More concepts of abstract syntax

    -

    Dependent types, variable bindings, semantic definitions

    +

    Dependent types

    -

    Transfer modules

    +

    Higher-order abstract syntax

    +

    Semantic definitions

    + +

    Case study: grammars of formal languages

    + +

    Transfer modules

    + +

    Practical issues

    + +

    Lexers and unlexers

    + +

    Efficiency of grammars

    + +

    Speech input and output

    + +

    Communicating with GF

    + +

    Embedded grammars in Haskell, Java, and Prolog

    +

    Alternative input and output grammar formats

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