org.stekikun.dolmen.syntax

Class PGrammars

java.lang.Object

org.stekikun.dolmen.syntax.PGrammars

public abstract class PGrammars
extends Object

Static utilities about PGrammars

Author:

Stéphane Lescuyer

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PGrammars.Args Enumeration representing the different constraints which can exist on the arguments of a symbol in a grammar: arguments can either be mandatory, forbidden, or there may be no constraint at all.
static class	PGrammars.Dependencies Represents the dependencies between the various non-terminals in some grammar.
static class	PGrammars.Sort This enumeration describes the various sorts which can characterize the kind of terminals or non-terminals (or more generally actual expressions) that can stand for some formal parameter in a parametric grammar.

Method Summary

Modifier and Type	Method and Description
static Map<String,List<PGrammars.Sort>>	analyseGrammar(PGrammar grammar, @Nullable PGrammars.Dependencies dependencies_, Reporter reporter) This analyses various rule applications in the parametric grammar grammar by inferring sorts for all the rules' formal parameters and checking that effective parameters in all applications are abiding by the constraints expressed by the sorts.
static PGrammars.Dependencies	dependencies(Map<String,PGrammarRule> rules) Computes the map of dependencies between the non-terminals of the given grammar rules, i.e. associates to every non-terminal in rules the set of non-terminals which appear in the right-hand side of productions for this non-terminal.
static void	findUnusedSymbols(PGrammar grammar, PGrammars.Dependencies deps, Reporter reporter) Analyses the grammar's dependencies deps to determine non-terminals and terminals which are not really being used in this grammar description.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

dependencies

public static PGrammars.Dependencies dependencies(Map<String,PGrammarRule> rules)

Computes the map of dependencies between the non-terminals of the given grammar rules, i.e. associates to every non-terminal in rules the set of non-terminals which appear in the right-hand side of productions for this non-terminal.

Parameters:

rules -

Returns:

the map of dependencies

findUnusedSymbols

public static void findUnusedSymbols(PGrammar grammar,
                                     PGrammars.Dependencies deps,
                                     Reporter reporter)

Analyses the grammar's dependencies deps to determine non-terminals and terminals which are not really being used in this grammar description.

For terminals, this amounts to not being used in any production, whereas for non-terminals, it means not being used transitively by a public non-terminal (in particular blocks of mutually recursive private non-terminals dot not "justify" each other, nor does continuation in a given non-terminal of course).

The problems found, if any, are reported into reporter.

Parameters:

grammar -

deps -

reporter -

analyseGrammar

public static Map<String,List<PGrammars.Sort>> analyseGrammar(PGrammar grammar,
                                                              @Nullable PGrammars.Dependencies dependencies_,
                                                              Reporter reporter)

This analyses various rule applications in the parametric grammar grammar by inferring sorts for all the rules' formal parameters and checking that effective parameters in all applications are abiding by the constraints expressed by the sorts.

All problems found are reported in reporter.

Parameters:

grammar -

dependencies_ - the dependencies between non-terminals in grammar, or null if the dependencies should be computed by the method

reporter -

Returns:

the map associating every non-terminal in grammar (even non-parametric ones) to the list of sorts that have been inferred for its formal parameters