Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: Notesfiles $Revision: 1.6.2.16 $; site ima.UUCP Path: utzoo!decvax!cca!ima!compilers From: compilers@ima.UUCP Newsgroups: mod.compilers Subject: Re: Attribute Grammars used in compi Message-ID: <136300021@ima.UUCP> Date: Mon, 6-Jan-86 22:13:00 EST Article-I.D.: ima.136300021 Posted: Mon Jan 6 22:13:00 1986 Date-Received: Wed, 8-Jan-86 02:43:37 EST Lines: 25 Approved: compilers@ima.uucp Nf-ID: #N:ima:136300021:000:1171 Nf-From: ima!compilers Jan 6 22:13:00 1986 [from Eduardo Krell ] In article <2287@burdvax.UUCP> wpl@burdvax.UUCP (William P Loftus) writes: >Since A is copying attributes i and k from a child and also calculating >attribute j from the same attributes, is it better to get the values (that >j is calculated) from the children nodes or to calculate them from attributes >in the same node? You might want to read the following paper: Martin, David and Chirica Laurian, ``An Order-Algebraic Definition of Knuthian Systems'', Math. Systems Theory No. 13 (1979). In this paper the authors prove that any AG with both synthesized and inherited attributes can be transformed into an equivalent AG with only synthesized attributes. They also show how to do it. The price you pay for doing this is that some attributes are now in the functional domain (i.e. some attributes are functions, not just plain values). The payoffs, however, are tremendous since now you can process your AG in a strictly top-down, syntax-directed scheme. -- Eduardo Krell UCLA Computer Science Department ekrell@ucla-locus.arpa ..!{sdcrdcf,ihnp4,trwspp,ucbvax}!ucla-cs!ekrell --------