ALGOL 68+(ID:4351/alg024)

Superlanguage of ALGOL 68 

Superlanguage of ALGOL 68

"The main difference between this grammar and an underlying context free grammar of ALGOL 68 + is that (a) symbols represented by the same mark are distinguished, and (b) various symbols are inserted in the grammar. "

Meertens, and  van Vliet. Mathematisch Centrum, Amsterdam

People:
Related languages
ALGOL 68 => ALGOL 68+   Superset
References:
  • L G. L T. Meertens, and J. C. van Vliet. "Underlying Context-Free Grammar of ALGOL 68+" Mathematisch Centrum, Amsterdam (Netherlands). Jui 81, 23p MC-IW-171/81 view details Abstract: ALGOL 68+ is a superianguage of ALGOL 68 which is powerful enough to describe the standard-prelude. In the defining documents, ALGOL 68 is defined using a two-level grammar. This type of grammar is not well suited for standard parsing techniques. The present report describes the construction of an underlying context-free grammar for ALGOL 68+ . The differences introduced by this transition are discussed. Finally, the resulting context-free grammar is given.
  • L G. L. T. Meertens, and J. C. Vanvliet. "Making ALGOL 68 + Texts Conform to an Operator-Priority Grammar" Mathematisch Centrum, Amsterdam (Netherlands). Oct 81 MC-IW-180/8 view details Abstract: A superlanguage of ALGOL 68, ALGOL 68+ which is powerful enough to describe the standard prelude is discussed. An operator precedence grammar can, through a simple right-to-left transduction scheme, be made to be of type LL(1). if, in addition, the grammar is an operator-priority grammar, an easy and consistent error recovery mechanism can be applied. An operator-priority grammar of ALGOL 68+ is cited. The main difference between this grammar and an underlying context free grammar of ALGOL 68+ is that (a) symbols represented by the same mark are distinguished, and (b) various symbols are inserted in the grammar. How these changes can be taken care of during the first phases of an ALGOL 68+ implementation is explained.
  • L G. L. T. Meertens, and J. C. Vanvliet. "On Top-down Parsing of ALGOL 68+" Mathematisch Centrum, Amsterdam (Netherlands). Nov 81, MC-IW-182/81 view details Abstract: A superlanguage of ALGOL 68, ALGOL 68+ , which is powerful enough to describe the standard prelude is considered. If a grammar is of type LL(1), this easily leads to a parsing method for that grammar implemented by a set of mutually recursive routines, one for each nonterminal of the grammar. An operator precedence grammar for ALGOL 68 + can, through a simple right-to-left transduction scheme, be made to be of type LL(1). If, in addition, the grammar is an operator-priority grammar, an easy and consistent error recovery mechanism can be applied. Both the algorithm for the transduction scheme and the subsequent top-down syntax analysis are discussed with emphasis on the treatment of incorrect input texts. The LL(1) grammar for ALGOL 68+ is given as well.
  • L. G. L T. Meertens, and J. C. van Vliet. "Operator-Priority Grammar for ALGOL 68+" Mathematisch Centrum, Amsterdam (Netherlands). Aug 81, 26p MC-IW-1 73/81 view details Abstract: If a grammar is of type LL(1), this easily leads to a parsing
    method for that grammar, implemented by a set of mutually recursive routines, one for each non-terminal of the grammar. ALGOL 68+ is a superlanguage of ALGOL 68 which is powerful enough to describe the standard-prelude. An operator-precedence grammar for ALGOL 68+ can, through a simple right-to-ieft transduction scheme, be made to be of type LL(1). If, in addition, the grammar is an operator-priority grammar, an easy and consistent error-recovery mechanism can be applied. In this report, such an operator-priority grammar for ALGOL 68+ is given. An account of the differences between the language generated by that grammar, and ALGOL 68+ , insofar as these are due to the transition to an operator-priority grammar, is given as well. These differences somehow have to be catered for during the parsing process.