Lexer Class Reference

Lexer which turns a token stream into a stream of unambigous symbols to be used by a parser. More...

#include <SelectionExprParser.h>

Collaboration diagram for Lexer:

Classes
struct	Symbol
	Struct grouping together the type and original string representation of a symbol. More...

Public Types
enum	Type {   AND = 0 , OR , LEFT , RIGHT ,   NOT , TRUE_LITERAL , FALSE_LITERAL , VAR ,   END }
	Enum over the possible symbols that can be extracted from the token stream. More...

Public Member Functions
	Lexer (const std::string &s)
	Constructor from a strig.
	Lexer (const Lexer &)=delete
	Disable copying of this class.
	Lexer (Lexer &&)=default
	Default move-constructor behaviour.
Symbol	nextSymbol ()
	Generate a new symbol from the token sequence.

Private Attributes
std::string	m_string
Tokenizer	m_tokenizer
Tokenizer::iterator	m_iterator

Detailed Description

Lexer which turns a token stream into a stream of unambigous symbols to be used by a parser.

Definition at line 38 of file SelectionExprParser.h.

Member Enumeration Documentation

Type

enum CP::DetailSelectionExprParser::Lexer::Type

Enum over the possible symbols that can be extracted from the token stream.

Enumerator
AND
OR
LEFT
RIGHT
NOT
TRUE_LITERAL
FALSE_LITERAL
VAR
END

Definition at line 50 of file SelectionExprParser.h.

            {
    AND = 0,
    OR,
    LEFT,
    RIGHT,
    NOT,
    TRUE_LITERAL,
    FALSE_LITERAL,
    VAR,
    END
  };

Constructor & Destructor Documentation

Lexer() [1/3]

CP::DetailSelectionExprParser::Lexer::Lexer

(

const std::string &

s

)

Constructor from a strig.

Definition at line 48 of file SelectionExprParser.cxx.

                               : m_string(s), m_tokenizer(m_string, {}) {
  m_iterator = m_tokenizer.begin();
}

Lexer() [2/3]

CP::DetailSelectionExprParser::Lexer::Lexer ( const Lexer & )

delete

Disable copying of this class.

Lexer() [3/3]

CP::DetailSelectionExprParser::Lexer::Lexer ( Lexer && )

default

Default move-constructor behaviour.

Member Function Documentation

nextSymbol()

auto CP::DetailSelectionExprParser::Lexer::nextSymbol

(

)

Generate a new symbol from the token sequence.

Definition at line 52 of file SelectionExprParser.cxx.

                                 {
  if (m_iterator == m_tokenizer.end()) {
    return Symbol{END, ""};
  }
  std::string t = *m_iterator;
  Type type;
  if (t == "&&")
    type = AND;
  else if (t == "||")
    type = OR;
  else if (t == "(")
    type = LEFT;
  else if (t == ")")
    type = RIGHT;
  else if (t == "!")
    type = NOT;
  else if (t == "true")
    type = TRUE_LITERAL;
  else if (t == "false")
    type = FALSE_LITERAL;
  else {
    // check if variable is valid
    const std::regex base_regex("^([^|()&! ]*)$");
    std::smatch base_match;
 
    if (!std::regex_match(t, base_match, base_regex)) {
      throw std::runtime_error("illegal variable encountered");
    } else {
      type = VAR;
    }
  }
 
  ++m_iterator;
  return Symbol{type, std::move(t)};
}

Member Data Documentation

m_iterator

Tokenizer::iterator CP::DetailSelectionExprParser::Lexer::m_iterator

private

Definition at line 75 of file SelectionExprParser.h.

m_string

std::string CP::DetailSelectionExprParser::Lexer::m_string

private

Definition at line 73 of file SelectionExprParser.h.

m_tokenizer

Tokenizer CP::DetailSelectionExprParser::Lexer::m_tokenizer

private

Definition at line 74 of file SelectionExprParser.h.

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The documentation for this class was generated from the following files:

• SelectionExprParser.h
• SelectionExprParser.cxx