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/* -*- C++ -*- */
// $Id$
// ========================================================================
//
// = LIBRARY
// orbsvcs
//
// = FILENAME
// Interpreter.h
//
// = AUTHOR
// Seth Widoff <sbw1@cs.wustl.edu>
//
// ========================================================================
#ifndef TAO_TCL_INTERPRETER_H
#define TAO_TCL_INTERPRETER_H
#include "Constraint_Nodes.h"
#include "Constraint_Visitors.h"
class TAO_Constraint_Evaluator;
class TAO_Constraint_Validator;
class TAO_Interpreter
{
// = TITLE
// TAO_Interpreter is the superclass for all interpreters. Its
// build tree method invokes the yacc parser to parse a constraint
// or preference string.
protected:
// = Initialization and termination methods.
TAO_Interpreter (void);
// Constructor.
~TAO_Interpreter (void);
// Destructor.
int build_tree (const char* preferences);
// Using the Yacc generated parser, construct an expression tree
// representing <constraints> from the tokens returned by it.
static int is_empty_string (const char* str);
TAO_Constraint* root_;
// The root of the expression tree, not equal to null if build_tree
// successfully builds a tree from the constraints.
private:
static ACE_SYNCH_MUTEX parserMutex__;
// This mutex protects the <build_tree> method from reentrance.
};
// Functions we need for parsing.
extern int yyparse (void);
extern void yyrestart (FILE*);
extern int yylex (void);
// Have yylex read from the constraint string, not from stdin.
#undef YY_INPUT
#define YY_INPUT(b, r, ms) (r = TAO_Lex_String_Input::copy_into(b, ms))
#undef yyerror
#define yyerror(x)
class TAO_Lex_String_Input
{
// = TITLE
// Have Lex read from a string and not from stdin. Essentially,
// the interpreter needs to call yylex() until EOF, and call
// TAO_Lex_String_Input::reset() with the new string, prior to
// calling yyparse.
public:
static void reset (char* input_string);
// Reset the lex input.
static int copy_into (char* buf, int max_size);
// Method lex will call to read from the input string.
private:
static char* string_;
static char* current_;
static char* end_;
// Pointers to keep track of the input string.
};
// The union used by lex and yacc to build the Abstract Syntax Tree.
typedef union
{
TAO_Constraint* constraint_;
} YYSTYPE;
extern YYSTYPE yylval;
extern YYSTYPE yyval;
#endif /* TAO_TCL_INTERPRETER_H */
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