cmp-lg/9709014 24 Sep 1997 op ed niques implementation and volves work frameworks Structure terpretation Kaplan The turity Haddo ck malisms ceedings in Linguistics ence ing useful This the y z Introduction esp ecially RANLP Supp orted ories constraints HPSG cessing Contemporary such fore development ed stract However or mars grammars for tion for grammars gardless by tion Supp orted In September p opularity comments Programming in Technion A a the the for of R the parsing have pap er shuly sfs nphil uni tuebin gen de A compiler e cient program suitable which The structures wide Recent don t such designed Mitkov machine Grammar interpreter malia inverted HPSG abstract and et of are Seminar of Bresnan applying practical of compiled led grammars by for whether fo cuses by al their on the declarative sp ectrum usually to as system grammars platform We HPSG inverts a Advances for pp the of N Universit at a linguistic p ermissible to under instructions parsing grant exist version Kl Fund machine that are Lexical form Languages Abstract b oth Shuly thank mathematical using Nicolov contemporary Minerva implementations HPSG the grammars f ur T ubingen the supp ort on di erent that Wilhelmstr to input A from for such more accepts grammars for or parsing one We grammar in one in and of b e development Sprachwissenschaft a an We theories language the includes Uni ed and developing Natural nature the Functional computational Wintner Head Driven grammars Categorial implementation structures Stip endien present theories control computed suitable For Tzigov anonymous extreme Induced generation and thus bidirectional Pollard Promotion are T ubingen Israeli N metho ds and as parsing in an then is Germany Nikolov obtain a Language and they The strategy input Chark the of a can generation compiler linguistic for are interpreter particular Ministry Computational reversible designed grammar such executed Komitee is not y original formal Platform genera genera sp ecify reviewer of Gram to of Grammar Grammar a there b e direct for eds Sag pro a how uni the Bulgaria Phrase Research this ab various Process re frame of gram devel of tech their ma Pro for Sci in in for Evgeniy Lab oratory Technion f sulting Prolog Carp enter piled run compile time into bach preter Prolog the erated tions ale A mechanisms programming mentation the gramming stract mars the use Further Kaci self way ated semantic ciency tical ably mar oretical to tegration where for gabr francez malia In From 1 Pollard the 1 new Recently of Computer implementation same time the and this grammars asp ects directly directly for Parsing We and A Gabrilovich some The machine Wintner for co de grammar programming representation Podelski from However of along infra structure the abstract slightly includes a the pap er sp ectrum emphasize formula of Israel as the ale for Systems technique parsing language earliest string high level such p oint Penn for parsing rules we to into of type uni cation into languages Computational abstract this Franz sp eci cally executes Science we increase techniques g without the more p erforming Institute show Haifa machine and cs technion ac il ale Prolog and a from For Prolog of Francez HPSG with language line advocate such Parts technique compiler We in system e g was and for and view parses also uni cation based compiles of elab orate generation b elow this instructions lies which has Department Generation ale prop ose Israel the the sp ecifying co de as most were proved generation of parsers feature relational language compile using designed of Nissim Prolog were of Java pap er compilation ale b een e ciency uni cation co de the the a grammars fo cusing Technology of grammar used it of a rather notably further Wintner Linguistics are grammar Prolog s improves designed input technique phrase string A Carp enter uni cations useful e g presented the e g structures that for or grammars malia the the p erformed and for Francez extensions than This implementing LIFE more as of Pro t on step input grammars grammar Prolog according executing was logic for engineer Prudian consider is an of the descrip internal its This the in the into an imple gener gram is many inter along prac A t com else gen Er pro a the into this is re z ab the in At ef it at a is a
ing the abstract machine approach has an ad the WAM that gave the language not only a go o d
ditional advantage Amalia s compiler incorp o e cient compiler but p erhaps more imp ortantly
rates an algorithm based on Samuelsson for an elegant op erational semantics
inverting grammars designed for parsing into a
The WAM immediately b ecame the starting
form more suitable for generation The compiler
p oint for many compiler designs for Prolog The
then pro duces co de for the inverted grammar us
techniques it delineates serve not only for Pro
ing exactly the same machine language Thus
log prop er but also for constructing compilers
the same grammar can b e compiled to two di er
for related languages parallel Prolog compilers
ent ob ject programs for the two di erent tasks
variants of Prolog that use di erent resolution
The interpreter executes b oth kinds of programs
metho ds extend Prolog with types or with record
in the same way only the initialization of the
structures etc An additional advantage of ab
machine s state and the format of the nal re
stract machines is that they are a useful to ol in
sults di er We thus obtain a uniform platform
formally verifying the correctness of compilers
for developing grammars serving b oth for parsing
Inverting grammars for generation
and for generation
We discuss the use of abstract machine tech
One of the attractions of declarative linguistic
niques for compilation in the next section and
theories such as HPSG is that a single grammar
sketch the algorithm that inverts a grammar for
formulated in the theory can b e used b oth for
generation in Section Section explains the
parsing and for generation While this is true in
dual op eration of the abstract machine and Sec
theory not many practical implementations of lin
tion lists some implementation details
guistic formalisms supp ort bidirectional grammar
pro cessing Many advantages of bidirectional nat
Why abstract machines
ural language systems are listed in Strzalkowski
where three options for reversibility are con
High level programming languages with dynamic
sidered pp xiii xxi A grammar is compiled
structures have always b een hard to develop com
into two separate programs parser and generator
pilers for A common technique for overcoming
requiring a di erent evaluation strategy The
the problems involves the notion of an abstract
parser and the generator are separate programs
machine It is a machine that on one hand
executed using the same evaluation strategy
captures the essentials of the high level language
The parser and the generator are one program
in its architecture and instruction set such that
and the evaluation strategy can handle it b eing
compiling from the source language to the ab
run in either direction Our solution falls into the
stract machine language b ecomes relatively sim
second category there is only one input grammar
ple On the other hand the architecture must
which is compiled into two di erent abstract ma
b e simple enough for the abstract machine lan
chine ob ject programs these two programs are
guage to b e easily interpretable on common ma
executed using exactly the same mechanism the
chines This technique also facilitates p ortable
interpreter and hence employ the same strategy
front ends for compilers as the machine language
This guarantees b oth ease of grammar develop
is abstract it can b e easily interpreted on di er
ment and maintenance and no loss of e ciency
ent concrete machines platforms
Grammars are usually oriented towards the
Abstract machines were used for various pro
analysis of a string and not towards generation
cedural and functional languages but they b e
from a usually nested semantic form In other
came prominent for logical programming lan
words rules re ect the phrase structure and not
guages since the introduction of the Warren Ab
the predicate argument structure It is therefore
stract Machine WAM Warren A t Kaci
desirable to transform the grammar in order to
for Prolog While Prolog has gained a recogni
enable systematic re ection of any given logical
tion as a practical implementation of the idea of
form in the pro ductions To this end we apply
programming in logic a metho d for interpreting
2
an inversion pro cedure based up on Samuelsson
the declarative logical statements was needed for
such an implementation to b e well founded Even
2
Samuelsson s inversion algorithm was developed for
though there were prior attempts to construct
de nite clause grammars Pereira Warren We
p orted it to a typed feature structure framework b oth interpreters and compilers for Prolog it was
grammar is inherently suitable for generation to render the rules with the nested predicate
argument structure corresp onding to that of in
Grammar inversion is p erformed as part of the
put logical forms Once the grammar is inverted
compilation The given grammar is enhanced in
the generation pro cess can b e directed by the in
a way that will ultimately enable to reconstruct
put semantic form elements of the input are con
the words spanned by the semantic forms To
sumed during generation just like words are con
achieve this aim each rule constituent is extended
sumed during parsing
by an additional sp ecial purp ose feature str in
the example grammar The value of this feature Figure depicts a simple example grammar in
3
for the rule s head is set to the concatenation of ale format prd stands for predicate a for ar
gument var for variable rst for restriction and
its values in the b o dy constituents to re ect the
conn for connective The rst rule creates a sen
original phrase structure of the rule
tence S out of a noun phrase NP and a verb
Among the other advantages of the abstract
phrase VP The semantics of the S denoted by
machine approach mentioned ab ove this tech
the variable R is obtained by applying the se
nique gives an express solution for the termina
mantics of the NP R R to that of the VP In
tion problem It is usually di cult to de ne when
the same way the second rule combining a deter
generation terminates but once the query is given
miner DET with a noun N to obtain an NP
as a sequence of semantic comp onents they are
applies the meaning of the DET to that of the N
consumed in a linear manner While generation
to obtain after two reductions that are incor
just like parsing is not guaranteed to terminate
p orated into the rule the meaning of the NP The
the termination criteria of parsing apply for our
lexical entries of three words are shown as well
generation scheme In other words generation in
Figure depicts part of the same grammar
our system can b e viewed as parsing consum
after inversion The inverted grammar re ects
ing input sequences of meaning comp onents
the semantic argument structure not the phrase
Uni ed parsing and generation
structure For example the rst rule creates
a sentence whose sem feature corresp onds to
Amalia employs a b ottom up chart based con
R R R R R from three comp o
trol unit where rules are evaluated from left to
nents an N R a VP R and a semantic
right The chart is used for storing active and
head R The string generated by the S en
complete edges The latter are represented as
co ded as the value of the str feature see b elow
p ointers to feature structures the former con
is the concatenation of the strings generated by
sist of a sequence of such p ointers for the part
the head the N and the VP For such rules to
of the edge prior to the dot and a p ointer to
b e applicable the lexicon has to b e inverted to o
the compiled co de for the part succeeding the
the words of the inverted grammar are atomic
dot For parsing edges span a sub sequence of
semantic formulae The last three rules add syn
the input string assigning it some structure For
tactic information to the semantics enco ded in the
generation edges span a sub form of the input
primitives In addition to these inverted rules a
semantic form also assigning it a structure that
semantic know ledge base is generated asso ciat
eventually determines a phrase whose meaning is
ing semantic primitives with words It is used in
that sub form It must b e noted that at run time
the nal stage of the generation when the actual
there is no notion of the particular task pars
words are generated
ing generation p erformed by the machine and
Grammars must satisfy certain requirements in
the e ect of the machine instructions is the same
order for them to b e invertible However the re
for b oth tasks
quirements are not overly restrictive and allow en
Amalia s op eration for generation di ers from
co ding of a variety of natural language grammars
parsing only in initialization and interpretation
In particular the semantics must b e enco ded by
of the results For parsing the input is a string
predicate argument structures What the inver
of words Each word is lo oked up in the lexi
sion in fact achieves is restructuring of a gram
con and its asso ciated feature structure or fea
mar this enables e ective treatment of the nested
ture structures in case the word is ambiguous
structure of logical forms so that the resulting
is entered in the main diagonal of the chart as
3
The signature is omitted for lack of space a complete edge Thus for the example gram
phrase syn syn cat s sem R sem
cat phrase syn syn cat np sem lambda var R rst R funct head
cat phrase syn syn cat vp sem lambda var R rst R funct
phrase syn syn cat np sem R sem
cat phrase syn syn cat det sem lambda var R rst R funct head
cat phrase syn syn cat n sem lambda var R rst R funct
every
word syn syn cat det
sem lambda var R
rst lambda var R
rst prd forall var R form bool conn if
wff R a R
wff R a R
a R a R
boy
word syn syn cat n sem lambda var R rst prd boy a R
sleeps
word syn syn cat vp sem lambda var R rst prd sleep a R
Figure A simple grammar
phrase syn syn cat s str R R R
sem R prd forall var R form conn if
wff R a R
wff R a R
a R a R
phrase syn cat n sem lambda rst R str R
phrase syn cat vp sem lambda rst R str R
lambda var R rst lambda var R rst R
word syn cat n sem R str R
R lambda var R rst R prd noun a R
word syn cat vp sem R str R
R lambda var R rst R prd v intrans a R
word syn cat det sem R str R
R lambda var R a R
rst lambda var R a R
rst R prd forall var R form conn if wff R wff R
a R a R
Figure The inverted grammar partial
mar and the input every b oy sleeps the items the entries of the chart are as
in the entries of the chart are as depicted in Figure The rst item enco des
depicted in Figure x boy x the second x sl eep x and the third
P Q x P x Q x
For generation the input is a semantic form
represented as an ale description of a feature It must b e clear that there do esn t have to b e
structure The chart is initialized with com a corresp ondence b etween the initial states
plete edges that corresp ond to elements in the of the chart in b oth tasks The semantic input is
input semantic form rather than to words For scanned and its elements are recursively selected
example if the input is a feature structure en in a pre de ned order that is induced by the re
co ding of x boy x sleep x the items in structuring of the grammar rules in particular
3 2
3 2
word
syn
sem
v ar
7 6
7 6
" #
sy n
7 6
7 det 6
arg cat
7 6
5 4
2 3
b oy
pr d
7 6
r st
" #
7 6
arg
7 6
a
6 7
7 6
prd
pr d
v ar
6 7
7 6
2 3
6 7
7 6
a
6 7
2 7 6 3
sem
v ar
6 7
7 6
6 7
" #
" #
6 7
7 6
atom
6 7 arg
6 7
6 7
7 6
4 5
6 7
prd
pr d
sleep
pr d
6 7
7 6
v ar
r st
6 7
6 7
7 6
6 7
a
a
6 7
7 6
6 7
3 2
6 7
7 6
arg
6 7
6 7
sem
7 6
3 2
3 2
6 7
6 7
7 6
" #
6 7
7 6
6 7
7 6
arg
sem
v ar
6 7
7 6
6 7
7 7 6 6
7 6
r st
2 3
6 7
7 6
sem
pr d
6 7
7 7 6 6
b o ol
v ar
7 6
6 7
7 6
6 7
7 7 6 6
7 6
pr d
6 7
7 6
if
conn
sem
a
6 7
7 7 6 6
7 6
6 7
r st
3 2
6 7
7 6
6 7
form
7 6
5 4
7 6
4 5
6 7
7 6
w
6 7
7 6
" #
7 6
6 7
7 6
arg
6 7
7 6
7 6
7 6
6 w 7
7 6
6 7
7 6
7 6
sem
pr d
7 6
4 5
v ar
5 4
4 5
5 4
7 6
7 6
a
7 6
a
7 6
7 6
3 2
a
7 6
arg
7 6
7 6
2 3
7 6
2 3
7 6
7 6
7 6
word
7 6
v ar
7 6
7 6
7 6
6 7
3 2
r st
syn
7 6
7 6
6 7
7 6
6 7 b o ol
sy n
7 6
7 6
6 7
7 6
6 7
n
cat
pr d
7 6
if
conn
7 6
6 7
7 6
6 7
7 6
2 3 r st
7 6
7 6
6 7
form
7 6
4 5
5 4
7 6
w
7 6
6 7
7 6
7 6
7 6
6 7 sem
v ar
7 6
6 7
7 w 6
" #
7 6
6 7
7 6
6 7 atom
5 4
sem
6 7
5 4
5 4
a
4 5
4 5
b oy
pr d
r st
a
a
3 2
word
syn
7 6
sy n
Figure Initial chart entries generation
7 6
vp
cat
7 6
3 2
7 6
7 6
7 6
sem
v ar
7 6
" #
7 6
7 6
atom
in The compiled co de of the second rule
sem
7 6
5 4
5 4
sleep
pr d
r st
is executed on every some trivial uni cations
a
take place but the more interesting ones bind R
of the rule to the value of the tag in the lexical
entry and R to the value of the path sem rst
Figure Initial chart entries parsing
A new active edge is created with these bindings
recorded and entered in The part of the
edge following the dot p oints to the second cate
arguments precede the predicate
gory in the b o dy of this rule Assume further that
Once the chart is initialized the same pro cess
this edge is combined with the complete edge
ing strategy is applied indep endently of the task
that is the lexical entry of b oy Several trivial
the compiled program is executed on the input
uni cations take place but the interesting ones
The basic op eration p erformed by the ob ject pro
in b oy and R bind R in the rule to the tag
grams is uni cation which is needed for b oth
of the rule to the value of sem rst in b oy Due
tasks Uni cation implements the dot movement
to reentrancies among the rule s constituents the
op eration that lies in the heart of chart based
obtained complete edge spanning whose
parsing and generation However dot movement
sem feature indeed enco des the semantics of ev
is interpreted di erently for b oth tasks since the
ery b oy Q x boy x Q x is as depicted
compiled grammar rules are di erent for pars
in Figure
ing dot movement go es over a sub part of the
input phrase for generation it covers a part of
Next we give a scenario of a generation pro cess
the input logical form
It is easy to see how the last three rules of the in
verted grammar are applicable to the three lexical Consider the e ect of dot movement for pars
entries of Figure resp ectively Assume an ac ing assume that an active edge corresp onding to
tive edge corresp onding to the rst rule is present the second rule with the dot in the initial p osition
in with the dot in the initial p osition Two is applied to the lexical entry of every present
3 2
3 2
phrase phrase
syn syn
7 6
7 6
sy n sy n
7 6
s np
cat cat
7 6
7 6
7 6
2 3
3 2
7 6
arg
7 6
3 2
" #
7 6
7 6
arg
7 6
7 6
6 7
7 6
7 6
sem
pr d
7 v ar 6
6 7
7 6
v ar
7 6
7 6
7 6
3 2
6 7
7 6
7 6
b o ol
7 6
a 7 6
6 7
7 6
7 6
7 6
2 7 6 3
6 7
7 if 6
conn
7 6
arg
7 6
7 6
7 6
6 7 " #
7 6
2 3
7 6
7 arg 6
7 6
7 6
6 7
7 6
7 6
7 6
6 7
7 6
7 6
6 7
pr d
7 6
7 6
b oy
pr d
v ar
w
7 6
6 7
7 6
7 6
6 7
7 6
6 7
7 6
sem
2 3
form
7 6
6 7 7 6
7 6
b o ol
6 7
7 6
6 7
7 6
a
7 6
6 7 7 6 sem
7 6
6 7
7 6
6 7
" #
7 6
if
conn
7 6
6 7
7 6
7 6
6 7 arg
7 6
6 7
7 6 6 7
" #
7 6
6 7
7 6
pr d 5 4
6 7
7 6
6 7
6 7
arg
5 4
sleep
pr d
7 6
6 7
7 6
w
6 7
7 6
6 7
r st
6 7
form
7 6
6 7
7 6
b oy
6 7 pr d
7 6
6 7
6 7
w
a
7 6
6 7
7 6
6 7
7 6
4 5
4 5
7 6
6 7
7 6
a
4 5
7 6
a
7 6
6 7
7 6
7 6
5 4
6 7
w
7 6
7 6
a
4 5
5 4
5 4
a
str h i
a
Figure Generation result
Figure Parsing intermediate result
in the example Figure the value of this feature
dot movements over the rst two elements in the
is not a list of words but rather a list of feature
b o dy of this rule bind R to the value of rst in
structures each of which corresp onds to i e is
the lexical entry of x boy x and R to the
subsumed by a lexical entry in the inverted gram
value of rst in x sl eep x An active edge with
mar A nal p ost pro cessing stage generates all
the dot in the p enultimate p osition is obtained in
the p ossible strings using this list and the seman
The next dot movement applies the co de
tic knowledge base
that was generated for the last b o dy element of
the rule to the lexical entry residing in R
Implementation
of the rule is uni ed with the value of the tag
This section describ es the input language for
in this entry since R was b ound by previous uni
Amalia grammars and touches on some imple
cations the value of prd is set to boy R of the
mentation details In particular it discusses the
rule is uni ed with the value of and the sec
di erences b etween Amalia and ale in terms of
ond predicate is set to sleep Finally R is uni ed
expressiveness and e ciency
with the value of rst rst in the lexical entry the
Amalia supp orts the same type hierarchies as
complete edge created spanning the entire input
ale do es with exactly the same sp eci cation syn
is depicted in Figure
tax This means that the user can sp ecify any
The chart algorithm ends up with a p ossibly
b ounded complete partial order as the type hi
empty set of feature structures spanning the en
erarchy Only immediate sub types are sp eci ed
tire input these are all the complete edges deriv
and the re exive transitive closure of the sub type
able from the input and the grammar rules there
relation is computed automatically by the com
is no notion of an initial symbol Of course if the
piler The sp ecial type bot must b e declared as
grammar is such that an in nite number of deriva
the unique most general type
tions can b e pro duced computations might not
Appropriateness to o is sp eci ed using ale s
terminate Amalia do es not incorp orate a sub
syntax by listing features at the type they are in
sumption check to test for spurious ambiguity
tro duced by The feature introduction condition
For parsing the results depict di erent structures
must b e ob eyed every feature must b e introduced
of the input string Ideally they contain some
by some most general type and is appropriate for
representation of the string s semantics This is
all its sub types However Amalia allows ap
also true for generation with a slight di erence
4
propriateness lo ops in the type hierarchy Type
according to the grammar inversion algorithm
constraints are not supp orted by Amalia
each resultant structure is guaranteed to have a
4
feature namely str that enco des a list of words
Appropriateness lo ops are handled by employing lazy
evaluation techniques at run time comprising the phrase generated As can b e seen
Amalia uses a subset of ale s syntax for de are supp orted by Amalia Lexical rules are not
scribing feature structures As a rule whenever supp orted in this version of Amalia Amalia s
Amalia supp orts ale s functionality it uses the syntax for phrase structure rules is similar to
same syntax In general Amalia supp orts to ale s with the exception of the cats sp eci
tally well typed p ossibly cyclic non disjunctive cation p ermitting a list of categories in the b o dy
feature structures Set values as in ale are of a rule which is not supp orted
not supp orted but list values are Amalia do es
The design details of the abstract machine are
not resp ect the distinction b etween intensional
outside the scop e of this pap er the reader is re
and extensional types Carp enter b Chapter
ferred to Wintner Francez Wintner
Also feature structures cannot incorp orate
for more information on the machine itself and
inequality constraints
to Gabrilovich for a detailed description of
The semantics of the logical descriptions as
the grammar inversion A practical description of
well as the op erator precedence follow ale As
Amalia its deviations from ale and a complete
in ale partial descriptions are expanded at com
user s guide are given in Wintner et al
pilation time Amalia s compiler p erforms type
Amalia is implemented in C augmented by
inference on partial descriptions rep orts any in
yacc lex and Tcl Tk Ousterhout It was
consistencies and then creates co de for the ex
tested on various Unix platforms and on IBM
panded structures To avoid in nite pro cessing in
PCs Two versions of Amalia exist an inter
the face of appropriateness lo ops where no nite
active easy to use graphically interfaced system
totally well typed structure that satis es the de
and a text oriented non interactive one The for
scription might exist the compiler stops expand
mer is intended for developing prototype gram
ing a structure if it is the most general structure
mars the latter is far more e cient but less user
of its type
friendly and is intended to b e used for batch
ale includes a built in de nite logic program
pro cessing In addition the system functions as
ming language Amalia do es not The entire
a graphical development framework for grammar
p ower of de nite clause sp eci cations is missing in
engineers by providing some tracing and debug
Amalia However a few common functions that
ging options The user can direct the system to
are external to the feature structure formalism
execute a program in its entirety to break at a
were added to the system and grammar sp eci
certain instruction or to pro ceed in steps stop
cations can use them These features are referred
ping after each executed instruction Throughout
to as goals although it must b e remembered that
the pro cess of grammar execution the abstract
they are far weaker than ale s goals
machine s internal state is displayed for the user
to insp ect The main data structure up on which
Amalia preserves ale s syntax in describing
feature structures are b eing built the heap is dis
lexical entries Multiple lexical entries may b e
played along with the machine s general purp ose
provided for each word separated by semicolons
and sp ecial purp ose registers Moreover the con
It also keeps ale s syntax in the de nition of
tents of the chart can b e graphically displayed at
empty categories or rules In contrast to ale
any time and the derived structure can b e recov
Amalia pro cesses empty categories at compile
ered Grammar development b ecomes an easier
time Each empty category is matched by the
simpler pro cess
compiler against each element in the b o dy of ev
ery rule if the uni cation succeeds a new rule is
The system was tested with a wide variety of
added to the grammar based up on the original
grammars mostly adaptations of existing ale
rule with the matched element removed Some
grammars While most of the example grammars
limitations apply for this pro cess which in the
are rather small we b elieve that the system can
general case is not guaranteed to terminate and
handle real scale grammar quite e ciently how
therefore the resulting grammar might not b e
ever to accommo date large type hierarchies some
equivalent to the original one
ma jor space optimizations must b e introduced
Amalia supp orts macros in a similar way to It is imp ortant to emphasize that Amalia do es
ale The syntax is the same and macros can have not provide the wealth of input sp eci cations ale
parameters or call other macros though not re do es On the other hand development of gram
cursively of course ale s sp ecial macros for lists mars in Amalia is made easier due to the GUI
and the improved p erformance over ale The July August
supp ort of generation is unique to our system
A t Kaci Hassan A t Kaci Warren s Abstract Machine A
Tutorial Reconstruction Logic Programming The MIT Press
To compare Amalia with ale we have used a
Cambridge Massachusetts
few b enchmark grammars The rst is an early
Carp enter Penn Bob Carp enter and Gerald Penn Compil
ing typed attribute value logic grammars In Harry Bunt and
version of an HPSG based Hebrew grammar de
Masaru Tomita editors Current Issues in Parsing Technolo
gies volume Kluwer
scrib ed in Wintner It consists of rules and
Carp enter a Bob Carp enter ALE the attribute logic engine
one empty category the type hierarchy contains
User s guide Technical rep ort Lab oratory for Computational
Linguistics Philosophy Department Carnegie Mellon University
types and features and the lexicon contains
Pittsburgh PA December
words The second is an HPSG based gram
Carp enter b Bob Carp enter The Logic of Typed Feature Struc
mar for a subset emphasizing relative clauses of
tures Cambridge Tracts in Theoretical Computer Science Cam
bridge University Press
the Russian language describ ed in Gabrilovich
Erbach Gregor Erbach ProFIT Prolog with features in
Estrin It consists of rules and lexical en
heritance and templates CLAUS Rep ort Computerlinguis
tik Universit atdes Saarlandes D Saarbr ucken Germany
tries the type hierarchy contains types and
July
features The third example is a simple grammar
Franz Alex Franz A parser for HPSG Rep ort CMU LCL
n n
Lab oratory for Computational Linguistics Department of
generating the language fa b j n g Both
Philosophy Carnegie Mellon University Pittsburgh PA
July
systems were used to compile the same grammar
and to parse the same strings The results of a
Gabrilovich Estrin Evgeniy Gabrilovich and Arkady Estrin
An HPSG grammar for the Russian language To app ear as a
p erformance comparison of Amalia and ale are
technical rep ort Lab oratory for Computational Linguistics the
Technion
listed in Figure all times are in seconds n in
Gabrilovich Evgeniy Gabrilovich Natural language generation
dicates the input string s length and r the num
by abstract machine M Sc thesis Technion Israel Institute of
Technology Haifa Israel In preparation
b er of results While the execution times for the
Haddo ck et al Nicholas Haddo ck Ewan Klein and Glyn Mo
last grammar are less impressing the di erences
rill editors Categorial Grammar Uni cation and Parsing
volume of Working Papers in Cognitive Science University
in compilation time indicate a ma jor advantage
of Edinburgh Center for Cognitive Science
in using Amalia for instructional purp oses in
Kaplan Bresnan R Kaplan and J Bresnan Lexical func
such cases grammars are compiled over and over
tional grammar A formal system for grammatical represen
tation In J Bresnan editor The Mental Representation of
again while they are usually executed only a few
Grammatical Relations pages MIT Press Cambridge
Mass
times Limited exp eriments we have conducted
Ousterhout John K Ousterhout Tcl and the Tk Toolkit
reveal that generation as well as compilation for
Addison Wesley Professional Computing Series Addison Wesley
generation is slower than parsing we
Pereira Warren Fernando C N Pereira and David H D War
do not know of go o d b enchmarks for generation
ren De nite clause grammars for language analysis a survey
of the formalism and a comparison with augmented transition
networks Arti cial Intel ligence
task ale Amalia
Grammar
Pollard Sag Carl Pollard and Ivan A Sag Head Driven
Compilation
Phrase Structure Grammar University of Chicago Press and
CSLI Publications
Parsing n r
Parsing n r
Prudian Pollard Derek Prudian and Carl Pollard Pars
ing head driven phrase structure grammar In Proceedings of
Parsing n r
the rd Annual Meeting of the Association for Computational
Grammar
Linguistics Chicago IL University of Chicago
Compilation
Samuelsson Christer Samuelsson An e cient algorithm for
Parsing n r
surface generation In Proceedings of the International Joint
Parsing n r
Conference on Arti cial Intel ligence
Parsing n r
Strzalkowski Tomek Strzalkowski editor Reversible Gram
Parsing n r
mar in Natural Language Processing The Kluwer International
Series in Engineering and Computer Science Kluwer Academic
Parsing n r
Publishers
Grammar
Warren David H D Warren An abstract Prolog instruction
Compilation
set Technical Note SRI International Menlo Park CA
Parsing n
August
Parsing n
Wintner Francez Shuly Wintner and Nissim Francez An
Parsing n
abstract machine for typed feature structures In Proceedings
Parsing n
of the th Workshop on Natural Language Understanding and
Logic Programming pages Lisb on May
Figure Performance comparison of ale and
Wintner Shuly Wintner An Abstract Machine for Uni cation
Grammars PhD thesis Technion Israel Institute of Technol
Amalia
ogy Haifa Israel January
Wintner et al Shuly Wintner Evgeniy Gabrilovich and Nis
sim Francez AMALIA Abstract MAchine for LIinguistic Ap
plications user s guide Lab oratory for Computational Linguis
References
tics Computer Science Deparmtent Technion Israel Institute of
Technology Haifa Israel January
A t Kaci Podelski Hassan A t Kaci and Andreas Podelski
Towards a meaning of LIFE Journal of Logic Programming