parser.hpp (cpp-lecture/lambda/parser.hpp)

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#ifndef PARSER_HPP
#define PARSER_HPP

#include <exception>
#include <list>
#include "lex.hpp"
#include "symbol-table.hpp"
#include "types.hpp"

namespace LambdaCalc {

   /*
      Parser for simple expressions:

      expr --> identifier
      expr --> integer
      expr --> '(' expr expr ')'
      expr --> '(' lambda identifier expr ')'
      expr --> '(' define identifier expr ')'
      expr --> '(' if expr expr expr')'
   */

   class Parser {
      public:
     class Exception: public std::exception {
        public:
        Exceptionsp; Exception(conTokenpan> Token& token, const std::string& message);
           virtu~Exceptionnbsp;~Exception() throw();
           virtual const chawhatpan>* what() const throw();
        private:
           std::string msg;
     };

  Parser ParsLexLex& leSymbolTableble& symtab);

  FunctionPtr; FunctionPgetFunctionion() throw(Exception);

      private:
  Lexsp; Lex& lex; // input channel
  SymbolTable; SymbolTable& symtab; // used for macros

  Token; Token token; // current token
     bool tokenConsumed; // true, if we need to fetch the next token

     std::list<std::string> bindings; // lexically scoped bindings

     vonextToken nextToken();
  Token; TokgetTokenken();
     unsigned ifindBindingbsp;findBinding(const std::string& varname);
  FunctionPtr; FunctionPparseExpressionion() throw(Exception);
   };

} // namespace LambdaCalc

#endif