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Syntax-directed Translation
Syntax-directed translation refers to a method of compiler implementation where the source language translation is completely driven by the parser. A common method of syntax-directed translation is translating a string into a sequence of actions by attaching one such action to each rule of a grammar. Thus, parsing a string of the grammar produces a sequence of rule applications. SDT provides a simple way to attach semantics to any such syntax. Overview Syntax-directed translation fundamentally works by adding actions to the productions in a context-free grammar, resulting in a Syntax-Directed Definition (SDD).Aho, Alfred V. Compilers: Principles, Techniques, & Tools. Boston: Pearson/Addison Wesley, 2007. Actions are steps or procedures that will be carried out when that production is used in a derivation. A grammar specification embedded with actions to be performed is called a ''syntax-directed translation scheme'' (sometimes simply called a 'translation scheme'.) Each symbol i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compiler
In computing, a compiler is a computer program that Translator (computing), translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a lower level language, low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program.Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A ''cross-compiler'' produces code for a different Central processing unit, CPU or operating system than the one on which the cross-compiler itself runs. A ''bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parser
Parsing, syntax analysis, or syntactic analysis is a process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar by breaking it into parts. The term ''parsing'' comes from Latin ''pars'' (''orationis''), meaning part (of speech). The term has slightly different meanings in different branches of linguistics and computer science. Traditional sentence parsing is often performed as a method of understanding the exact meaning of a sentence or word, sometimes with the aid of devices such as sentence diagrams. It usually emphasizes the importance of grammatical divisions such as subject and predicate. Within computational linguistics the term is used to refer to the formal analysis by a computer of a sentence or other string of words into its constituents, resulting in a parse tree showing their syntactic relation to each other, which may also contain semantic information. Some parsing a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grammar
In linguistics, grammar is the set of rules for how a natural language is structured, as demonstrated by its speakers or writers. Grammar rules may concern the use of clauses, phrases, and words. The term may also refer to the study of such rules, a subject that includes phonology, morphology (linguistics), morphology, and syntax, together with phonetics, semantics, and pragmatics. There are, broadly speaking, two different ways to study grammar: traditional grammar and #Theoretical frameworks, theoretical grammar. Fluency in a particular language variety involves a speaker internalizing these rules, many or most of which are language acquisition, acquired by observing other speakers, as opposed to intentional study or language teaching, instruction. Much of this internalization occurs during early childhood; learning a language later in life usually involves more direct instruction. The term ''grammar'' can also describe the linguistic behaviour of groups of speakers and writer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semantics
Semantics is the study of linguistic Meaning (philosophy), meaning. It examines what meaning is, how words get their meaning, and how the meaning of a complex expression depends on its parts. Part of this process involves the distinction between sense and reference. Sense is given by the ideas and concepts associated with an expression while reference is the object to which an expression points. Semantics contrasts with syntax, which studies the rules that dictate how to create grammatically correct sentences, and pragmatics, which investigates how people use language in communication. Lexical semantics is the branch of semantics that studies word meaning. It examines whether words have one or several meanings and in what lexical relations they stand to one another. Phrasal semantics studies the meaning of sentences by exploring the phenomenon of compositionality or how new meanings can be created by arranging words. Formal semantics (natural language), Formal semantics relies o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syntax
In linguistics, syntax ( ) is the study of how words and morphemes combine to form larger units such as phrases and sentences. Central concerns of syntax include word order, grammatical relations, hierarchical sentence structure (constituency), agreement, the nature of crosslinguistic variation, and the relationship between form and meaning (semantics). Diverse approaches, such as generative grammar and functional grammar, offer unique perspectives on syntax, reflecting its complexity and centrality to understanding human language. Etymology The word ''syntax'' comes from the ancient Greek word , meaning an orderly or systematic arrangement, which consists of (''syn-'', "together" or "alike"), and (''táxis'', "arrangement"). In Hellenistic Greek, this also specifically developed a use referring to the grammatical order of words, with a slightly altered spelling: . The English term, which first appeared in 1548, is partly borrowed from Latin () and Greek, though the L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Context-free Grammar
In formal language theory, a context-free grammar (CFG) is a formal grammar whose production rules can be applied to a nonterminal symbol regardless of its context. In particular, in a context-free grammar, each production rule is of the form : A\ \to\ \alpha with A a ''single'' nonterminal symbol, and \alpha a string of terminals and/or nonterminals (\alpha can be empty). Regardless of which symbols surround it, the single nonterminal A on the left hand side can always be replaced by \alpha on the right hand side. This distinguishes it from a context-sensitive grammar, which can have production rules in the form \alpha A \beta \rightarrow \alpha \gamma \beta with A a nonterminal symbol and \alpha, \beta, and \gamma strings of terminal and/or nonterminal symbols. A formal grammar is essentially a set of production rules that describe all possible strings in a given formal language. Production rules are simple replacements. For example, the first rule in the picture, : \lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaprogramming
Metaprogramming is a computer programming technique in which computer programs have the ability to treat other programs as their data. It means that a program can be designed to read, generate, analyse, or transform other programs, and even modify itself, while running. In some cases, this allows programmers to minimize the number of lines of code to express a solution, in turn reducing development time. It also allows programs more flexibility to efficiently handle new situations with no recompiling. Metaprogramming can be used to move computations from runtime to compile time, to generate code using compile time computations, and to enable self-modifying code. The ability of a programming language to be its own metalanguage allows reflective programming, and is termed ''reflection''. Reflection is a valuable language feature to facilitate metaprogramming. Metaprogramming was popular in the 1970s and 1980s using list processing languages such as Lisp. Lisp machine hardware ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacompiler
In computer science, a compiler-compiler or compiler generator is a programming tool that creates a parser, interpreter, or compiler from some form of formal description of a programming language and machine. The most common type of compiler-compiler is called a parser generator. It handles only syntactic analysis. A formal description of a language is usually a grammar used as an input to a parser generator. It often resembles Backus–Naur form (BNF), extended Backus–Naur form (EBNF), or has its own syntax. Grammar files describe a syntax of a generated compiler's target programming language and actions that should be taken against its specific constructs. Source code for a parser of the programming language is returned as the parser generator's output. This source code can then be compiled into a parser, which may be either standalone or embedded. The compiled parser then accepts the source code of the target programming language as an input and performs an action or ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
META II
META II is a Domain-specific language, domain-specific programming language for writing compilers. It was created in 1963–1964 by Dewey Val Schorre at University of California, Los Angeles (UCLA). META II uses what Schorre called ''Syntax (programming languages), syntax equations''. Its operation is simply explained as: Each ''syntax equation'' is translated into a recursive Function (computer programming), subroutine which tests the input string for a particular phrase structure, and deletes it if found. Meta II programs are compiled into an Interpreter (computing), interpreted byte code language. VALGOL and SMALGOL compilers illustrating its capabilities were written in the META II language, VALGOL is a simple algebraic language designed for the purpose of illustrating META II. SMALGOL was a fairly large subset of ALGOL 60. Notation META II was first written in META I, a hand-compiled version of META II. The history is unclear as to whether META I was a full implementation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TREE-META
The TREE-META (or Tree Meta, TREEMETA) Translator Writing System is a compiler-compiler system for context-free languages originally developed in the 1960s. Parsing statements of the metalanguage resemble augmented Backus–Naur form with embedded tree-building directives. Unparsing rules include extensive tree-scanning and code-generation constructs. History TREE-META was instrumental in the development of NLS (oN-Line System) and was ported to many systems including the UNIVAC 1108, GE 645, SDS 940, ICL 1906A, PERQ, and UCSD p-System. Example This is a complete example of a TREE-META program extracted (and untested) from the more complete (declarations, conditionals, and blocks) example in Appendix 6 of the ICL 1900 TREE-META manual. That document also has a definition of TREE-META in TREE-META in Appendix 3. This program is not only a recognizer, but also outputs the assembly language for the input. It demonstrates one of the key features of TREE-META, which is tree pat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attribute Grammar
An attribute grammar is a formal way to supplement a formal grammar with semantic information processing. Semantic information is stored in attributes associated with terminal and nonterminal symbols of the grammar. The values of attributes are the result of attribute evaluation rules associated with productions of the grammar. Attributes allow the transfer of information from anywhere in the abstract syntax tree to anywhere else, in a controlled and formal way. Each semantic function deals with attributes of symbols occurring only in one production rule: both semantic function parameters and its result are attributes of symbols from one particular rule. When a semantic function defines the value of an attribute of the symbol on the left hand side of the rule, the attribute is called ''synthesized''; otherwise it is called ''inherited''. Thus, synthesized attributes serve to pass semantic information up the parse tree, while inherited attributes allow values to be passed from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
