* * It has evolved out of the first-cut grammar for a minimal * "human-readable" syntax, which is described in the proposal submitted * to the W3C Working Group on the Rule Interchange Format (RIF) by * Harold Boley et al., on April 23, 2006. It is meant to be able * to express the abstract syntax form taken by conditions of the * rules that appear to be common to a reasonably large variety of * families of rule languages. The proposal in question is available * from the public RIF WG mail archive: * [RIF] Extensible Design. This Jacc grammar specification is a * literal transcription of the BNF rules given in the above reference. * *
* * This version of the RCL grammar is annotated for simple XML serialization. * *
* * We give below the Jacc grammar rules for RCL. Note that the grammar * their combination defines is LALR(1). * *
* * This HTML file is the root of a hyperlinked documentation allowing one * to explore the grammar via navigation through its elements - rules, * terminal and non-terminal symbols. The comments accompanying some rules * come from the original documents. It also contains the pure Yacc rules. * The documentation is generated by Jacc from the Jacc grammar specified * in file RCL.grm. Along with this Jacc * grammar file, there are other supporting source * files. * *
* * Essentially, the rule format is that of Yacc. As in Yacc, Jacc rules may * be annotated with semantic actions, in the form of code involving the * rule's RHS constituents (denoted by $1, $2, * ..., $n - the so-called pseudo-variables where the index * n in $n refers to the order of RHS * constituents. Such actions appear between curly braces ('{' and * '}') wherever a symbol may appear in a rule's RHS. * * Jacc also allows an additional form of annotation in the RHS of a rule * to indicate the XML serialization pattern of the abstract syntactic * tree (AST) node corresponding to a derivation with this rule. This XML * serialization meta-annotation comes between square brackets * ('[' and ']') and is of the form: * *
* [ XmlTag n_1 ... n_k ] ** * where
XmlTag is an identifier to use as XML tag for this
* node in the XML serialization of the AST, and the n_k's
* are a sequence of numbers denoting positions of symbols in the RHS of
* the rule (as for pseudo-variables but without '$'). The
* number sequence indicates the order in which subnodes are to be
* serialized. For example, the annotated rule:
*
*
* QUANTIF
* : 'Exists' Var_plus '(' CONDIT ')'
* [ Exists 2 4 ]
* ;
*
*
* means that an AST node for this rule will be serialized thus:
*
* * <Exists> * (Xml serialization of Var_plus) * (Xml serialization of CONDIT) * </Exists> ** * Rules without XML serialization annotation follow a default behavior: * the serialization is the concatenation of those of its RHS's * constituents, eliminating punctuation tokens (i.e., empty nodes * and literal tokens - namely, tokens that do not carry a value). * *
* * For example, see the two test files Test.rcl * and Test2.rcl. * Running the command rcl on them produces the * output shown in Test.run. */ //////////////////////////////////////////////////////////////////////// %package ilog.rif; %include keywords.grm // RCL language reserved keywords %include ParserCode.grm // Code for setting params and showing xml serialization %token Name Fun Rel Value Var // NB: Var is a token (i.e., the '?' is part of it) %start RCL %% RCL : CONDIT { showXml(); } /** * This rule is just a root for the non-terminal symbol denoting * having recognized an RCL construct. For now, it recognizes a RIF * condition (a $CONDIT$) as defined in * [RIF] Extensible Design. Its semantic action amounts to print * out the XML serialization of the parsed $CONDIT$ construct on the * standard output. */ ; %include RCL_basis.grm %include RCL_valobj.grm // %include RCL_constant.grm %include RCL_forall.grm %include RCL_neg.grm %include RCL_naf.grm %include RCL_nafneg.grm %%