A. V. Aho and J. D. Ullman. The Theory of Parsing, Translation and Compiling, Vol. I: Parsing. Prentice-Hall, Englewood Cliffs, N.J., 1972.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....computational scheme. This can be rectified by refreshing the CR, i.e. by reinitializing the value of components periodically. If the refreshing is done over the regular number of points, we find that this is analogous to a well known program optimizing transformation, called loop unrolling [1]. In the general case we will use multidimensional loop unrolling [9] but here we start with a two dimensional one as an example. Given F (i) which has to be evaluated for i = 0; n, assuming that n 1 = m Delta q, we can compute the required values using inner unrolling F (j Delta q ....

Aho, A., and Ullman, J. The Theory of Parsing, Translation and Compiling, Vol.2. Englewood Cliffs, N.J.: Prentice-Hall, 1972.

....how the actor alters its output concepts based on its input concepts. 5 . STATE TRANSITION DIAGRAMS This section illustrates the process of obtaining an R Spec Graph from a state transition diagram. We take the definition of state transition diagrams (STD) based on input tokens as described in [24]. We will translate state transition diagrams into conceptual graphs by using instances of the concept STATE to represent each state, a demon to represent each transition, and instances of DATA to represent each input and output token. The demon s semantics are described in [25] they are somewhat ....

....directed from process a k towards process a i in R Spec. Mark c. preserve intermediate flows. end loop end Algorithm 2b. This concludes the translation scheme for data flow diagrams. State Transition Translation Scheme We use the standard definition of state transitions based on input symbols [24], although we may be able to generalize our definition to include any event as an input symbol or output symbol. In the standard definition, each event therefore means the arrival of an input symbol or the creation of an output symbol. We will translate state transition diagrams into conceptual ....

A.V. Aho, The Theory of Parsing, Translation and Compiling, Prentice-Hall, Vol. I, Englewood Cliffs, New Jersey 1972.

....not consider complexity results at all, neither of recognition by various classes of sequential or parallel Turing machines nor of succinctness (see e.g. 52] that is a measure of the size of the description of a language. We have chosen to present material which is not available in textbooks [17, 29, 1, 47, 28, 4, 30, 32, 2] (more precisely not available in more than one textbook) because it is on the borderline between classical stuff and advanced topics. However, we feel that a succinct exposition of these results may give some insight in the theory of context free languages for advanced beginners, and also provide ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling., volume 1. Prentice-Hall, 1973.

....can lead to the definition of complex systems is given in the following. In [Seki et al., 1989] a tabular method has been presented for the recognition of general LCFR languages as a generalization of the well known CYK algorithm for the recognition of CFG s (see for in stance [Younger, 1967] and [Aho and Ullman, 1972]) In the following we will apply such a general method to the recognition of LCFRS(2) with the aim of hav ing an intuitive understanding of why it might be difficult to parse unrestricted crossing configurations. Let w be an input string of length n. In Figure 2, the case of a production p : A ....

A. V. Aho and J. D. Ull- man. The Theory of Parsing, Translation and Compiling, volume 1. Prentice-Hall, Englewood Cliffs, N J, 1972.

....that the parser does not maintain a chart as in chart ilarsing. Our method also prr)vides an elegant solution to the problem of multi part of.speech words such as that . The MLR parser and its parsing table generator have been implemented at Carnegie Mellon University, I Introduction LR parsers [1, 2] have been developed originally for programming language of compilers. An LR parser is a shift reduce parser which is deterministically guMed by a parsirg table indicating whal action should be taken next. The parsing table can be obtained automatically from a context free phrase structure ....

Aho, A. V. and Ullman, J.D. The Theory of Parsing, Translation and Compiling. Prentice-Hall, Englewood Cliffs, N.J., 1972.

....of offline parsable grammars which we will call here the class of explicitly offiine parsable grammars is the class of DCGs whose context free skeleton is a proper context free grammar. that is, a grammar without rules of the type A [ empty productions) or of the type A B (chain rules) [1]. This subclass is much less problematic to parse than the full class of offline parsable DCGs (for insumce a leA comar parsing algorithm will work) However, it is an easy consequence of the GGNF result that, for any offiine parsable DCG, there exists an explicitly offiine parsable DCG equivalent ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling, volume 1: Parsing. Prentice-Hall, Englewood Cliffs, NJ, 1972.

....symbol. Moreover, the number of automaton states is reduced. Our timings show that, especially for highly ambiguous grammars, the parser is significantly faster than a standard GLR parsertl 2 Definitions 2. 1 Languages, Grammars, Recursion We use standard notation as defined in texts such as [2], 10] or [21] Let an alphabet be a finite set of symbols. A lansuase over an alphabet T is a set of strings over T. The notation T denotes the set of all strings over T including the empty string, denoted by c. Set T is defined as T = T c . Similarly for string a 6 T , the notation a ....

....table, which the parser is driven by. The initial configuration is the triple (#, w t, c) where # is the initial stack symbol and cvp(#) c. The final, accepting configuration is (# [ Z t , r) where (#, w t, # [ Z t, 7r) cvp(# [ Z t ) S t, and r is a right parse of w. [2], 20] 25] and [26] provide further information on GLR parsing. 3 Reductions between Shifts of Two Adjacent Symbols Grammars without right and hidden left recursions have a property which proves to be useful in the context of GLR parsing. Namely, after shifting an input symbol, the number of ....

Aho, A.V., Ullman, J.D. The Theory of Parsing, Translation and Compiling. Vol. 1: Parsing, Vol. 2: Compiling, Prentice-Hall, New York, 1972.

....the use of language generators, called grammars. The translation of a language into one understandable by a machine is carried out by compilers, which are also built using grammars and associated rules of translation. A prevalent method is the so called semantic attribute method due to Irons [1], 26] 27] An automation of this process for particular grammars has been done with the very wellknown programs LEX and YACC which are available free by FTP on an INTERNET site. These programs are heavily used by people interested in compilers or friendly interfaces. In addition to having ....

....implemented in the software package CalICo [16] 12] which we are developing in Bordeaux. 2 Definitions and notation This section summarizes briefly the notions needed for understanding this paper. A more complete background can be acquired from Berstel [3] Ginsburg [23] Aho and Ullmann [1]. Let X be a nonempty set called alphabet. The elements of X are called letters. A word is a finite sequence of letters from X. The empty word is usually denoted by e. Let u and v be two words on X, u=u 1 . u p and v=v 1 . v q . We define the concatenation of two words to be uv=u 1 . u p v 1 ....

A. Aho, J. Ullman, The theory of parsing, translation and compiling, Prentice Hall, Englewood Cliffs, NJ, 1973.

....has many good properties of context free grammars, for example being closed under union, concatenation, homomorphisms, being semilinear, etc. Also, there exist polynomial parsing algorithms for this class [9, 6] There exist several well known pumping lemmas for context free languages (see e.g. [1]) which state some necessary conditions for a language to be contextfree. One of these lemmas has been proven by W. Ogden [7] In the current paper we prove that coupled context free languages must satisfy some conditions that are similar to those in Ogden s lemma, actually Ogden s result is a ....

A. V. Aho, J. D. Ullman. The Theory of Parsing, Translation and Compiling. Vol. 1: Parsing. Prentice-Hall, Inc. Englewood Clis, N. J. 1972.

....where a less general but faster algorithm would be more appealing. In addition, the requirement for a grammar to be in the binary normal form is also a very inconvenient constrain. There exist numerous linear time parsing algorithms for various subclasses of the context free grammars; the LL(k) [1, 4] and LR(k) 1, 2] algorithms and some of their variations are the most widely used among them. It turns out that the SLL(k) strong LL(k) context free parsing method can be effectively extended for the case of conjunctive grammars. The construction and explanation of the resulting algorithm is ....

....but faster algorithm would be more appealing. In addition, the requirement for a grammar to be in the binary normal form is also a very inconvenient constrain. There exist numerous linear time parsing algorithms for various subclasses of the context free grammars; the LL(k) 1, 4] and LR(k) [1, 2] algorithms and some of their variations are the most widely used among them. It turns out that the SLL(k) strong LL(k) context free parsing method can be effectively extended for the case of conjunctive grammars. The construction and explanation of the resulting algorithm is the main concern of ....

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A. V. Aho and J. D. Ullman, The Theory of Parsing, Translation and Compiling, Vol. I: Parsing, Prentice-Hall, 1972.

....symbol (only in the qualisign class) or a relational need r = t; y) where t C and y is a nite set (of syntactic properties) The logical type of r is de ned by the function as follows: t; y) A if t = and B, otherwise. Nondeterminism is assumed to be implemented by backtracking ([1]) In the de nition of we will allow a reference to the current value of the evaluation mode, forward( f ) or backward( b ) via the function mode . Finally, we will make use of a graph G = C; E) where E= E d [ E h , and E d ; E h C C are, respectively, the set of directed edges and ....

Aho, A.V., Ullman, J.D.: Parsing, volume 1 of The Theory of Parsing, Translation and Compiling. Prentice-Hall, (1972)

....relations producing single symbols is output delimited. 4 Testing SXMDG (Weak) output distinguishability and (strong) memory completeness as well as their more relaxed counterparts are addressed in this section. Output distinguishability will take place for SXMDG having a LL(1) like property [1]. For a string x; first 1 (x) denotes the set fa j a 2 A; 9r 1; x = r ayg; r 2 DM: Lemma 1. Any SXMDG X d ; d 2 DM 0 with the property that for any two rules S x 1 2 P i ; S x 2 2 P j ; i 6= j it follows first 1 (x 1 ) first 1 (x 2 ) then X d is output distinguishable. Proof. If ....

A. Aho, J. Ullman, The Theory of Parsing, Translation and Compiling, Vol. I: Parsing, Prentice-Hall, Englewood Clis, N.J, 1972.

....W. Lauridsen Mikkel Thorup Abstract A linear time algorithm is presented for nding dominators in control ow graphs. 1 Introduction Finding the dominator tree for a control ow graph is one of the most fundamental problems in the area of global ow analysis and program optimization [2, 3, 4, 5, 10, 15]. The problem was rst raised in 1969 by Lowry and Medlock [15] where an O(n 4 ) algorithm for the problem was proposed (as usual, n is the number of nodes and m the number of edges in a graph) The result has been improved several times (see e.g. 1, 2, 17, 20] and in 1979 an O(m (m;n) ....

.... and program optimization [2, 3, 4, 5, 10, 15] The problem was rst raised in 1969 by Lowry and Medlock [15] where an O(n 4 ) algorithm for the problem was proposed (as usual, n is the number of nodes and m the number of edges in a graph) The result has been improved several times (see e.g. [1, 2, 17, 20]) and in 1979 an O(m (m;n) algorithm was found by Lengauer and Tarjan [14] Finally, at STOC 85, Dov Harel [11] announced a linear time algorithm. Assuming Harel s result, linear time algorithms have been found for many other problems (see e.g. 4, 5, 10] However, Harel never produced the ....

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A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling, volume II. Prentice-Hall, Englewood Clis, N.J., 1972.

....in control ow graphs. Key words. Control ow analysis, dominators, algorithms AMS subject classi cations. 68Q25, 68N20 1. Introduction. Finding the dominator tree for a control ow graph is one of the most fundamental problems in the area of global ow analysis and program optimization [2, 3, 4, 6, 12, 17]. The problem was rst raised in 1969 by Lowry and Medlock [17] where an O(n 4 ) algorithm for the problem was proposed (as usual, n is the number of nodes and m the number of edges in a graph) The result has been improved several times (see e.g. 1, 2, 19, 22] and in 1979 an O(m (m;n) ....

.... and program optimization [2, 3, 4, 6, 12, 17] The problem was rst raised in 1969 by Lowry and Medlock [17] where an O(n 4 ) algorithm for the problem was proposed (as usual, n is the number of nodes and m the number of edges in a graph) The result has been improved several times (see e.g. [1, 2, 19, 22]) and in 1979 an O(m (m;n) algorithm was found by Lengauer and Tarjan [16] Here is the inverse Ackermann s function. Finally, at STOC 85, Dov Harel [13] announced a linear time algorithm. Based on Harel s result, linear time algorithms have been found for many other problems (see e.g. 4, 6, ....

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A. Aho and J. Ullman, The Theory of Parsing, Translation and Compiling, vol. II, PrenticeHall, Englewood Clis, N.J., 1972.

.... recursive relation: M b (u) i] 8 : Pr(H i u) juj = 1; max 0 t juj;h;l f Pr(H i H h H l ) M b (u (t) P ) h] M b (u (juj Gammat) S ) l] g; juj 1: This relation is implemented by a probabilistic version of the Kasami Younger Cocke (CYK) parser (see [7] and [1]) in analogy with the Viterbi algorithm (see also [4] Prefix and suffix upper bounds Let u = w 1 : wn be a string in Sigma n . We define an jNj Theta 1 array M p (u) as follows: M p (u) i] Pr(max : H i hu Sigma i) We will present some relations to compute M p (u) Let f M p ....

A. V. Aho and J. D. Ullman. The Theory of Parsing, Translation and Compiling, volume 1. Prentice-Hall, Englewood Cliffs, NJ, 1972.

....in a formal sense the class sdFun. The work of this author has been supported by the Deutsche Forschungsgemeinschaft (DFG) 1 1 Introduction In many situations it is appropriate, to describe the semantics of strings that are generated by some context free grammar, in a syntax directed way [Iro61, AU71, AU73, Knu68] (for short: sd way) Then, the meaning of a string is expressed in terms of the meanings of its substrings. For example, the translation of a high level language program into machine code is often described in a syntax directed way [Ind79] Then, the translation of a program construct, e.g. an if ....

....e.g. an if then else statement, is described in terms of the translation of its constituents, i.e. the condition and the two alternatives of the if then else statement. Up to now there exists various formalizations of the concept of sd translation: ffl generalized sd translation schemes [AU73] ffl attribute grammars [Knu68] ffl denotational semantics [SS71, Gor79] ffl affix grammars [Kos71] ffl total deterministic macro tree to string transducers [CF82, Eng81, EV86] ffl context free hypergraph grammar based syntax directed translation schemes [EH89] In this paper we start from ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling, Vol. I and Vol. II. Prentice-Hall, 1973.

....stochastic k Testable Automata (k TA) which are equivalent to k Grams [3, 4, 8, 15] A set of 50100 input output paired (text) sentences (for each of the 3 different output languages) was obtained using a semi automatic procedure. This procedure was driven by a Syntax Directed Translation Scheme [1] governed by English context free grammars for the basic and extended MLA tasks, along with the associated grammars for Spanish and German [5] From this set, 100 input output sentences were randomly selected for speech input testing purposes. The remaining 50000 pairs were used to automatically ....

A. Aho, J. Ullman: The Theory of Parsing, Translation and Compiling, 1, Prentice Hall, 1972

....C DFA and C NFA denote respectively the deterministic and non deterministic C FSA. Theorem 1 For each C FSA M , there exists a C DFA MD accepting the same languages, i.e. such that L(M) L(MD ) Proof: The proof is given in [3] It consists in adapting to C DFA the NFA determinization algorithm [2]. Definition 6. Given a C tuple of languages L, the canonical C FSA of L, denoted by M(L) is the minimal C DFA accepting exactly L. 2.3. Derived C FSA Definition 7. For any set S, a partition is a set of pairwise disjoint nonempty subsets of S whose union is S. Let s denote an element of S ....

....may be used. This operation consists in merging the states giving rise to non determinism. It allows to obtain the lowest deterministic upper bound of the current C FSA in the lattice which is eventually more general. This operation should not be confused with the classical determinization process [2] which produces an equivalent deterministic machine, but eventually outside the lattice. Definition 11. Let M = Q; q s ; Sigma; Gamma; ffi; be a C FSA. The deterministic merge operation may be stated as follows: while (9q 2 Q; 9a 2 Sigma; 9q 1 ; q 2 2 ffi(q; a) q 1 6= q 2 ) merge(M, q 1 ....

A. Aho and J. Ullman. The Theory of Parsing, Translation and compiling, Vol 1 : Parsing. Englewood Cliffs, Prentice-Hall, 1972.

....i.e. trees that satisfy a certain property. Can we derive an algorithm that constructs a heap from its inorder (and preorder) traversal Such an algorithm would correspond directly to an algorithm for precedence parsing: a parsing method for a restricted type of grammars (cf. Swier] Floyd] [Aho]) In this chapter we explore these problems in the spec calculus. In section 5.2 we introduce the labeled binary trees and de ne the inorder traversal, it , of such a tree. In section 5.3 we construct the reverse of it using the compositional method of chapter 4. Sections 5.4, 5.5 and 5.6 show ....

....made that an algorithm like the one we constructed above, corresponds directly to a precedence parsing algorithm. To investigate this claim we take a look at the theory of precedence parsing. A precedence parsing algorithm is one of the simplest instances of a shift reduce parsing algorithm (cf. [Aho]) and its origins can be found in [Floyd] Precedence oriented parsing techniques were among the rst techniques to be used in the construction of parsers for programming languages and a number of variants of precedence parsing have appeared in the literature. The grammars that can be parsed by ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling. Vol I: Parsing. Prentice-Hall, Englewood Clis, NJ, 1972.

....no counterpart in this set up of a Combinatory Categorial Grammar. 2 A simple parsing method In order to give a taste how parsing with Lambek categorial grammars works, we first describe a simple, non deterministic bottom up style parser which is based on the idea of shift reduce parsing (cf. [2]) 2.1 Basic categorial grammars A bottom up parser (i.e. a parser which works from the categories of the input string towards the goal category) for a basic categorial grammar is a backward chaining theorem prover which implements the calculus BS in definition 5. The parser operates on ....

.... which corresponds to the root of a BN derivation for the substring between positions i and j is represented by a chart item: x i j 8 The following definition is nothing more than the categorial grammar variant of the table based bottom up algorithm by Cocke Kasami Younger (CKY algorithm, cf. [2]) Definition 8 (Chart parser BC for basic categorial grammars) Only the relevant pieces of information are mentioned. Everything else is thought to be left unchanged. w i word; s goal category; l length of sentence. w 1 ; w l ( x 1 0 1 : x l l Gamma 1 l x i 2 L(w i ) ....

Alfred V. Aho and Jeffrey D. Ullman. The Theory of Parsing, Translation and Compiling. Prentice Hall, Englewood Cliffs, N.J., 1972.

....not consider complexity results at all, neither of recognition by various classes of sequential or parallel Turing machines nor of succinctness (see e.g. 52] that is a measure of the size of the description of a language. We have chosen to present material which is not available in textbooks [17, 29, 1, 47, 28, 4, 30, 32, 2] (more precisely not available in more than one textbook) because it is on the borderline between classical stuff and advanced topics. However, we feel that a succinct exposition of these results may give some insight in the theory of context free languages for advanced beginners, and also provide ....

....the family of contextfree languages by briefly presenting the two most usual subfamilies appearing in syntactical analysis. Given a word w over the alphabet A, define F irst k (w) as the prefix of length k of w; if jwj k, F irst k (w) is equal to w. We may now define LL grammars Definition 6.3. [1, 38] A context free grammar G = V; P ) over the terminal alphabet A is a LL(k) grammar if S Gamma uXm Gamma uffm Gamma uv S Gamma uXm 0 Gamma uff 0 m 0 Gamma uv 0 62 Jean Michel Autebert, Jean Berstel, and Luc Boasson (with u; v; v 0 2 A and ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling., volume 1. Prentice-Hall, 1973.

....such lookaheads are named LR(k) parsers, and the grammars that may be parsed by them are called LR(k) grammars. A detailed description of the theory behind the various LR parsing techniques, along with formal proofs of the the correctness of the algorithms presented, may be found in Aho and Ullman [AU72]. A more practical description of LR parsers appears in Aho and Ullman [AU77] and Aho, Sethi and Ullman [ASU86] and a general survey of LR parsing can be found in Aho and Johnson [AJ74] Substring recognizers have been considered in several works on recovery from syntax errors. Richter [Ric85] ....

....In this paper we show that the substring recognition problem for LR(k) grammars is not any harder than the full string recognition problem. We present an algorithm for the LR(k) substring recognition problem that runs in linear time, the same time complexity as the original LR parsing algorithm [AU72]. While previous substring parsing algorithms such as Cormack s [Cor89] modified the LR parsing tables to accommodate for substring recognition, our algorithm modifies the parsing algorithm itself, while leaving the original LR parsing tables intact 1 . We use a data structure, the Forest ....

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A. V. Aho and J. D. Ullman. The Theory of Parsing, Translation and Compiling, Vol. I: Parsing. Prentice-Hall, Englewood Cliffs, N.J., 1972.

....In this paper we show that the substring recognition problem for LR(k) grammars is not any harder than the full string recognition problem. We present an algorithm for the LR(k) substring recognition problem that runs in linear time, which is similar to that of the original LR parsing algorithm [AU72]. While previous substring parsing algorithms such as Cormack s [Cor89] modified the LR parsing tables to accommodate for substring recognition, our algorithm modifies the parsing algorithm itself, while leaving the original LR parsing tables intact. We introduce a data structure, the Forest ....

....7 2 1 8 11 8 ) Fig. 2a Fig. 2b Fig. 2c Fig. 2d Fig. 2e Fig. 2f = Figure 2: Structure of the FSS throughout the execution of algorithm SSR on the example In Proceedings of POPL 92 3 Correctness Now we sketch the correctness of SSR. The reader is referred to Aho and Ullman [AU72] for a comprehensive proof of correctness of the original LR parsing algorithm LRP. In our proof, we rely on the correctness of LRP, namely that given an LR grammar G, and an input string x, LRP accepts x if and only if x 2 L(G) We therefore concentrate on proving the following theorem : ....

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A. V. Aho and J. D. Ullman. The Theory of Parsing, Translation and Compiling, Vol. I: Parsing. Prentice-Hall, Englewood Cliffs, N.J., 1972. In Proceedings of POPL-92

....trees of the input sequence. The complexity of parsing words according to context free grammars is usually considered as having theoretically two parameters: the length of the input sequence and the size of the grammar, namely the number of rules or the sum of the lengths of rule bodies (see e.g. [AU72, AU73] for a survey) In practice, one tends to consider the size of the grammar as a constant. This approximation is acceptable if the size of the grammar is of a reasonable order of magnitude. As a matter of fact, existing parsers are usually applied to context free grammars with at most a few ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling. Vol. II : Compiling. Prentice-Hall, Englewoof Cliffs, N.J., 1973.

....trees of the input sequence. The complexity of parsing words according to context free grammars is usually considered as having theoretically two parameters: the length of the input sequence and the size of the grammar, namely the number of rules or the sum of the lengths of rule bodies (see e.g. [AU72, AU73] for a survey) In practice, one tends to consider the size of the grammar as a constant. This approximation is acceptable if the size of the grammar is of a reasonable order of magnitude. As a matter of fact, existing parsers are usually applied to context free grammars with at most a few ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling. Vol. I : Parsing. Prentice-Hall, Englewoof Cliffs, N.J., 1972.

....L P;k , and then to use this automaton to scan the text in linear time. This approach has been considered, for exemple, by Ukkonen [Ukk85] One way is to start by considering a non deterministic automaton (NDFA) recognizing L P;k and to construct an equivalent DFA by the standard algorithm [AU72]. This takes a time exponential in the number of the NDFA s states. A well known such NDFA, recalled by Melichar [Mel95] has O(km) states. Another way is to directly construct a DFA recognizing L P;k . Ukkonen [Ukk85] has computed a DFA for approximate string matching (with insertions, deletions ....

A. Aho and J. Ullman. The Theory of Parsing, Translation and Compiling, volume 1: Parsing. Prentice Hall, Englewood Cliffs, New York, 1972.

....processing. 1 Introduction LR parsing, one of the strongest and most efficient class of parsing strategies for context free grammars (CFGs) is a two fold process: first, the grammar is compiled into a finite state machine called LR automaton, which has two associated tables of actions and goto s [1]; second, a push down automata with the LR automaton as finite state engine is used to parse strings according to the grammar. The efficiency of the parsing relies on the implementation of this run time phase, which is the center of our discussion in this paper. The class of grammars that can be ....

....LR(0) D Shift LR(0) D P red LR(0) D Reduce LR(0) F LR(0) FEarley 2. 3 LR parsing with lookahead In order to obtain a parsing schemata for LR(1) we must introduce the notion of lookahead into items, as is done in the classical construction of finite state control for LR(1) parsers [1]. The items in LR parsing schemata can be obtained by item refinement of LR(0) items if we consider that in Earley and LR(0) parsing schemata, each item represents a set of items having the same dotted rule and indexes but probably different lookahead: ILR = f[A ff:fi; b; i; j]g 1 In LR(0) ....

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A. V. Aho and J. D. Ullman. The Theory of Parsing, Translation and Compiling, volume 1--2. Prentice Hall, 1972.

....of the gesture where the structure was implemented by an equivalent of a finite state machine with no learning involved. Syntactic pattern recognition is based on the advances of the formal language theory and computational linguistics. The most definitive text on these topics still remains [1]. The authors present a thorough and broad treatment of the parsing concepts and mechanisms. A vast amount of work in syntactic pattern recognition has been devoted to the areas of image and speech recognition. A review of syntactic pattern recognition and related methods can be found in [27] ....

A. V. Aho and Ullman J. D. The Theory of Parsing, Translation and Compiling. Volume 1: Parsing. Prentice Hall, Englewoods Cliffs, N.J., 1972.

....as elimination of left recursion, elimination of empty derivation, unfolding and factorization. Finally, the technique is applied to DCGs and a Prolog implementation of the abstract form and of the transforms is described. 1 Introduction Text books (e.g. the Dragon book [1] and others [2, 3]) are rich and precise when dealing with the manipulations (analysis, transformation) of pure Context Free Grammars (CFGs) They also present parsing techniques for Attributed CFGs (ACFGs) and specialized analysis for ACFGs like the detection of circular dependencies. However, they are ....

.... itself, and one for its derivative (remember that the derivatives of some functions are built using both their subparts and the derivatives of their subparts) A similar example is used by Aho and Ullman for illustrating the formalism of Generalized Syntax Directed Translation Scheme (GSDTS, [3], 9.3.1, p. 758) The application is described by the following DCG grammar. axiom(Drv) exp(Exp, Drv) exp(Exp PExp, Drv PDrv) exp(Exp, Drv) 0 ] prod(PExp, PDrv) exp(Exp, Drv) prod(Exp, Drv) prod(PExp PrExp, PExp PrDrv) PDrv PrExp) prod(PExp, PDrv) 0 ] ....

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A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling, Vol. II: Compiling. Prentice-Hall, 1973.

....as elimination of left recursion, elimination of empty derivation, unfolding and factorization. Finally, the technique is applied to DCGs and a Prolog implementation of the abstract form and of the transforms is described. 1 Introduction Text books (e.g. the Dragon book [1] and others [2, 3]) are rich and precise when dealing with the manipulations (analysis, transformation) of pure Context Free Grammars (CFGs) They also present parsing techniques for Attributed CFGs (ACFGs) and specialized analysis for ACFGs like the detection of circular dependencies. However, they are ....

A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling, Vol. I: Parsing. Prentice-Hall, 1972.

....different techniques of the Web wrapper implementation, we introduce here one important aspect common for all of them, namely the wrapper reliability. We explain the problem for the example of the rule based parsing. It concerns the fundamental difference between the standard use of parsers [AhUl72] and our use for html parsing. In the standard use, a grammar based parser is invoked to scan input files of a highly rigorous structure with well defined syntax and as free of inconsistencies as any program is. If such a program contains a syntax error, an error message is generated and no ....

A. V. Aho, J. D. Ullman: The Theory of Parsing, Translation and Compiling, 2 volumes, Prentice-Hall, 1972.

....in control flow graphs. Key words. Control flow analysis, dominators, algorithms. AMS subject classifications. 68Q25, 68N20. 1 Introduction Finding the dominator tree for a control flow graph is one of the most fundamental problems in the area of global flow analysis and program optimization [2, 3, 4, 5, 10, 15]. The problem was first raised in 1969 by Lowry and Medlock [15] where an O(n 4 ) algorithm for the problem was proposed (as usual, n is the number of nodes and m the number of edges in a graph) The result has been improved several times (see e.g. 1, 2, 17, 20] and in 1979 an O(mff(m; n) ....

.... and program optimization [2, 3, 4, 5, 10, 15] The problem was first raised in 1969 by Lowry and Medlock [15] where an O(n 4 ) algorithm for the problem was proposed (as usual, n is the number of nodes and m the number of edges in a graph) The result has been improved several times (see e.g. [1, 2, 17, 20]) and in 1979 an O(mff(m; n) algorithm was found by Lengauer and Tarjan [14] Finally, at STOC 85, Dov Harel [11] announced a linear time algorithm. Based on Harel s result, linear time algorithms have been found for many other problems (see e.g. 4, 5, 10] Harel s description was, however, ....

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A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling, volume II. PrenticeHall, Englewood Cliffs, N.J., 1972.

....how the actor alters its output concepts based on its input concepts. 5. STATE TRANSITION DIAGRAMS This section illustrates the process of obtaining an R Spec Graph from a state transition diagram. We take the definition of state transition diagrams (STD) based on input tokens as described in [24]. We will translate state transition diagrams into conceptual graphs by using instances of the concept STATE to represent each state, a demon to represent each transition, and instances of DATA to represent each input and output token. The demon s semantics are described in [25] they are somewhat ....

....from process a k towards process a i in R Spec. Mark c. preserve intermediate flows. end if end loop end Algorithm 2b. This concludes the translation scheme for data flow diagrams. State Transition Translation Scheme We use the standard definition of state transitions based on input symbols [24], although we may be able to generalize our definition to include any event as an input symbol or output symbol. In the standard definition, each event therefore means the arrival of an input symbol or the creation of an output symbol. We will translate state transition diagrams into conceptual ....

A.V. Aho, The Theory of Parsing, Translation and Compiling, Prentice-Hall, Vol. I, Englewood Cliffs, New Jersey 1972.

....nonterminal A is the set fXjA Af Xg. single generating A nonterminal A is said to single generate nonterminal B if A B. In the starters, enders, and followers we also include some nonterminals. The reason we do this, contrary to standard terminology (cf. FIRST 1 and FOLLOW 1 in [1]) is that nonterminals often give more information than the terminals alone, because they capture a number of terminals in one name. For this reason, nonterminals which are predicates are not included. On the other hand, there is a class of terminals which are not relevant for most purposes and ....

A.V. Aho and J.D. Ullman. Parsing, volume 1 of The Theory of Parsing, Translation and Compiling. Prentice-Hall, 1972.

....for associating semantic meaning with the input[2] and if the input is invalid, give an explanation of why and where the input is not valid. There is a well established theory and practice for developing parsers, either by hand or using a parser generator, that verify the validity of input [3, 1]. Unfortunately, the other tasks of a parser are less well supported[2] Systems using a parser perform actions based on the meaning of the input which is derived from its syntactic structure. For example, a parser in a compiler may be annotated with actions that directly translate the source to a ....

....Declaration found when statement expected E Declaration found when statement expected Breadth First Parser Error: begin, line 1, column 9, appears out of place deleting token. Figure 5. Second error handling example. 7 Related Work The field of parsing is very well established[3, 1]. Traditional parsing is based on the assumption of examining the input in a left to right manner, examining each token only once. Lookahead parsers (LL(k) 9, 10] and LR(k) 11] for k 1) allow more than just the next token to be used to guide the parse. Back tracking parsers[12] allow a token to ....

A. Aho and J. Ullman, Theory of parsing, translation and compiling, volume 1, Prentice-Hall, Englewood Cliffs, New Jersey, 1972.

....items. LR PARSING FOR LIG The class of LR parsing strategies constitutes one of the strongest and most efficient class of parsing strategies for Context free Grammars. The class of grammars that can be deterministically analyzed using LR parsing with k lookahead symbols are called LR(k) grammars [2]. They are useful for describing programming languages, but they are very limited when they are used for other purposes, for example parsing of natural languages. If we consider LR parsing tables in which each entry can contain several actions, we obtain non deterministic LR parsing, often known ....

....and therefore there will be more conflicts in the run time phase of the algorithm. These conflicts could be avoided by including that kind of contextual information during the compilation of the LR automaton. In order to do that, we need to change the definition of the functions first and follow [2]: Definition 2 The function first( Gamma) with Gamma 2 V T [ VN [V I ] is defined as follows: 1. If Gamma = a 2 V T first(a) fag. 2. If Gamma then 2 first( Gamma) 3. If Gamma 0 Gamma 1 : Gamma i : Gamma n oe = mgu( Gamma; Gamma 0 ) then first( Gamma 1 oe) ....

[Article contains additional citation context not shown here]

Aho, Alfred V. and Ullman, Jeffrey D., The Theory of Parsing, Translation and Compiling, Prentice Hall, 1972.

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A. V. Aho and J. D. Ullman. The Theory of Parsing, Translation and Compiling, Vol. I: Parsing. Prentice-Hall, Englewood Cliffs, N.J., 1972.

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Alfred V. Aho and Je#rey D. Ullman. The Theory of Parsing, Translation and Compiling, volume II.: Compiling. Prentice-Hall, Englewood Cli#s, N.J., 1973.

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Alfred V. Aho and Je#rey D. Ullman. The Theory of Parsing, Translation and Compiling, volume I.: Parsing. Prentice-Hall, Englewood Cli#s, N.J., 1972.

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A. V. Aho, J. D. Ullman: The Theory of Parsing, Translation and Compiling. Vol. 1: Parsing. Prentice Hall (1972).

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Alfred. V. Aho and Je#rey D. Ullman. The Theory of Parsing, Translation and Compiling, volume 1. Prentice-Hall, Englewood Cli#s, NJ, 1972.

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Aho, A. V. and Ullman, J. D., The Theory of Parsing, Translation and Compiling, Prentice Hall, Englewood Cliffs, New Jersey, 1973.

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Alfred V. Aho and Jeffrey D. Ullman. The Theory of Parsing, Translation and Compiling. Prentice-Hall, Englewood Cliffs, NJ, 1973. I and II.

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A. Aho and J.Ullman. The Theory of Parsing,Translation and Compiling. Prentice-Hall, 1972.

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A.V. Aho and J.D. Ullman. The Theory of Parsing, Translation and Compiling, volume 1-2. Prentice-Hall, Englewood Cli, New Jersey, U.S.A., 1973.

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Aho, A.V., Ullman, J.D.: The Theory of Parsing, Translation and Compiling, Vol.

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Alfred V. Aho, and Jeffrey D. Ullman, The Theory of Parsing, Translation and Compiling, Vol. 1, Prentice-Hall, Englewood Cliffs, NJ, 1972.

No context found.

A. V. Aho and J. D. Ullman, The Theory of Parsing, Translation and Compiling, Volume 1, PrenticeHall, Englewood Cliffs, New Jersey, 1972.

No context found.

Alfred V. Aho and Jerey D. Ullman. The Theory of Parsing, Translation and Compiling. Prentice Hall, 1972.

No context found.

Alfred V. Aho and Jeffrey D. Ullman. The Theory of Parsing, Translation and Compiling, volume 1. Prentice-Hall, 1972.

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