uscript::Scanner Class Reference

#include <scanner.h>

Public Member Functions
	Scanner ()
void	SetSource (const char *_start)
Token	ScanToken ()
Token	MakeToken (TokenType type) const
Token	ErrorToken (const char *message) const
bool	IsAtEnd () const
char	Advance ()
bool	Match (char c)
void	SkipWhitespace ()
Token	String ()
Token	Number ()
Token	Identifier ()
TokenType	IdentifierType () const

Private Attributes
const char *	start
const char *	current

Detailed Description

Definition at line 44 of file scanner.h.

Constructor & Destructor Documentation

uscript::Scanner::Scanner

(

)

Definition at line 6 of file scanner.cc.

                       :
  start(NULL),
  current(NULL)
{}

Member Function Documentation

char uscript::Scanner::Advance

(

)

Definition at line 99 of file scanner.cc.

                             {
  current++;
  return current[-1];
}

uscript::Token uscript::Scanner::ErrorToken

(

const char *

message

)

const

Definition at line 175 of file scanner.cc.

                                                                 {
  uscript::Token token;
  token.type = uscript::TOKEN_ERROR; 
  token.start = message;
  token.length = (int)strlen(message);
  return token;
}

uscript::Token uscript::Scanner::Identifier

(

)

Definition at line 169 of file scanner.cc.

                                        {
  while (isAlpha(*current) || isDigit(*current)) Advance();

  return MakeToken(IdentifierType());
}

uscript::TokenType uscript::Scanner::IdentifierType

(

)

const

Definition at line 140 of file scanner.cc.

                                                      {
  static const std::vector<std::string> keywords {"and", "or", "if", "else", "for", "while", "return", "true", "false", "fun", "nil", "var", "print", "length", "fields"};
  static const std::vector<uscript::TokenType> keyword_types {
    uscript::TOKEN_AND,
    uscript::TOKEN_OR,
    uscript::TOKEN_IF,
    uscript::TOKEN_ELSE,
    uscript::TOKEN_FOR,
    uscript::TOKEN_WHILE,
    uscript::TOKEN_RETURN,
    uscript::TOKEN_TRUE,
    uscript::TOKEN_FALSE,
    uscript::TOKEN_FUN,
    uscript::TOKEN_NIL,
    uscript::TOKEN_VAR,
    uscript::TOKEN_PRINT,
    uscript::TOKEN_LENGTH,
    uscript::TOKEN_FIELDS
  };
  std::string comp = std::string(start, current);
  for (unsigned i = 0; i < keywords.size(); i++) {
    if (strcmp(comp.c_str(), keywords[i].c_str()) == 0) {
      return keyword_types[i];
    }
  }

  return uscript::TOKEN_IDENTIFIER;
}

bool uscript::Scanner::IsAtEnd

(

)

const

Definition at line 104 of file scanner.cc.

                                   {
  return *current == '\0';
}

uscript::Token uscript::Scanner::MakeToken

(

uscript::TokenType

type

)

const

Definition at line 108 of file scanner.cc.

                                                                  {
  uscript::Token token;
  token.type = type; 
  token.start = start;
  token.length = current - start;
  return token;
}

bool uscript::Scanner::Match

(

char

c

)

Definition at line 91 of file scanner.cc.

                                 {
  if (IsAtEnd()) return false;
  if (*current != c) return false;

  current ++;
  return true;
}

uscript::Token uscript::Scanner::Number

(

)

Definition at line 127 of file scanner.cc.

                                    {
  while (isDigit(*current)) Advance();

  if (*current == '.') { // && isDigit(current[1])) {
    // consume the '.'
    Advance();

    while (isDigit(*current)) Advance();
  }

  return MakeToken(uscript::TOKEN_NUMBER);
}

uscript::Token uscript::Scanner::ScanToken

(

)

Definition at line 48 of file scanner.cc.

                                       {
  SkipWhitespace();

  start = current;

  if (IsAtEnd()) {
    return MakeToken(uscript::TOKEN_EOF);
  }

  char c = Advance();

  if (isDigit(c)) return Number();
  if (isAlpha(c)) return Identifier();

  switch (c) {
    case '(': return MakeToken(uscript::TOKEN_LEFT_PAREN);
    case ')': return MakeToken(uscript::TOKEN_RIGHT_PAREN);
    case '{': return MakeToken(uscript::TOKEN_LEFT_BRACE);
    case '}': return MakeToken(uscript::TOKEN_RIGHT_BRACE);
    case ']': return MakeToken(uscript::TOKEN_RIGHT_BRACKET);
    case '[': return MakeToken(uscript::TOKEN_LEFT_BRACKET);
    case ';': return MakeToken(uscript::TOKEN_SEMICOLON);
    case ',': return MakeToken(uscript::TOKEN_COMMA);
    case '.': return MakeToken(uscript::TOKEN_DOT);
    case '-': return MakeToken(uscript::TOKEN_MINUS);
    case '+': return MakeToken(uscript::TOKEN_PLUS);
    case '/': return MakeToken(uscript::TOKEN_SLASH);
    case '*': return MakeToken(uscript::TOKEN_STAR);
    case '!':
      return MakeToken(Match('=') ? TOKEN_BANG_EQUAL : TOKEN_BANG);
    case '=':
      return MakeToken(Match('=') ? TOKEN_EQUAL_EQUAL : TOKEN_EQUAL);
    case '<':
      return MakeToken(Match('=') ? TOKEN_LESS_EQUAL : TOKEN_LESS);
    case '>':
      return MakeToken(Match('=') ?
                       TOKEN_GREATER_EQUAL : TOKEN_GREATER);
    case '"': return String();
  }

  return ErrorToken("Unexpected character.");
}

void uscript::Scanner::SetSource

(

const char *

_start

)

Definition at line 11 of file scanner.cc.

                                                 {
  start = _start;
  current = _start;
}

void uscript::Scanner::SkipWhitespace

(

)

Definition at line 16 of file scanner.cc.

                                    {
  while (1) {
    char c = *current;
    switch (c) {
      case '/': // comments
        if (current[1] == '/') {
          while (*current != '\n' && !IsAtEnd()) Advance();
        }
        else return;
        break;
      case '\n':
      case ' ':
      case '\r':
      case '\t':
        Advance();
        break;
      default:
        return;
    }
  }
}

uscript::Token uscript::Scanner::String

(

)

Definition at line 116 of file scanner.cc.

                                    {
  while (*current != '"' && !IsAtEnd()) {
    Advance();
  }

  if (IsAtEnd()) return ErrorToken("Unterminated string.");

  Advance();
  return MakeToken(uscript::TOKEN_STRING);
}

Member Data Documentation

const char* uscript::Scanner::current

private

Definition at line 46 of file scanner.h.

const char* uscript::Scanner::start

private

Definition at line 45 of file scanner.h.

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

• scanner.h
• scanner.cc