ECLR-attributed Grammar

	ECLR-attributed Grammar ECLR-attributed grammars are a special type of attribute grammars. They are a variant of LR-attributed grammar LR-attributed grammars are a special type of attribute grammars. They allow the attributes to be evaluated on LR parsing. As a result, attribute evaluation in LR-attributed grammars can be incorporated conveniently in bottom-up parsing. zyacc is ba ...s where an equivalence relation on inherited attributes is used to optimize attribute evaluation. EC stands for equivalence class. Rie is based on ECLR-attributed grammars. External links * http://www.is.titech.ac.jp/~sassa/lab/rie-e.html * M. Sassa, H. Ishizuka and I. Nakata: ECLR-attributed grammars: a practical class of LR-attributed grammars. ''Inf. Process. Lett.'' 24 (1987), 31–41. * M. Sassa, H. Ishizuka and I. NakataRie, a Compiler Generator Based on a One-pass-type Attribute Grammar ''Software—practice and experience'' 25:3 (March 1995), 229–250. Formal languages Compiler construction ... [...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 result of attribute evaluation rules associated with productions of the grammar. Attributes allow to transfer 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 parent node ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	LR-attributed Grammar LR-attributed grammars are a special type of attribute grammars. They allow the attributes to be evaluated on LR parsing. As a result, attribute evaluation in LR-attributed grammars can be incorporated conveniently in bottom-up parsing. zyacc is based on LR-attributed grammars. They are a subset of the L-attributed grammars, where the attributes can be evaluated in one left-to-right traversal of the abstract syntax tree. They are a superset of the S-attributed grammars, which allow only synthesized attributes. In yacc, a common hack is to use global variables to simulate some kind of inherited attributes and thus LR-attribution. External links * http://www.cs.binghamton.edu/~zdu/zyacc/doc/zyacc_4.html * Reinhard Wilhelm Reinhard Wilhelm (born June 5, 1946) is a German computer scientist. Life and work Wilhelm was born in , today part of the municipality of Finnentrop, Westphalia. He studied math, physics and mathematical logic at University of Münster and ...: LL- and LR ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Formal Languages In logic, mathematics, computer science, and linguistics, a formal language consists of string (computer science), words whose symbol (formal), letters are taken from an alphabet (formal languages), alphabet and are well-formedness, well-formed according to a specific set of rules. The alphabet of a formal language consists of symbols, letters, or tokens that concatenate into strings of the language. Each string concatenated from symbols of this alphabet is called a word, and the words that belong to a particular formal language are sometimes called ''well-formed words'' or ''well-formed formulas''. A formal language is often defined by means of a formal grammar such as a regular grammar or context-free grammar, which consists of its formation rules. In computer science, formal languages are used among others as the basis for defining the grammar of programming languages and formalized versions of subsets of natural languages in which the words of the language represent concepts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]