/// Consume whitespace and comments
void Input::eatWS()
{
// Until the end of the whitespace
for (;;)
{
// Consume whitespace characters
if (isspace(peekCh()))
{
readCh();
continue;
}
// If this is a single-line comment
if (matchStr("//"))
{
// Read until and end of line is reached
for (;;)
{
char ch = readCh();
if (ch == '\n' || ch == '\0')
break;
}
continue;
}
// If this is a multi-line comment
if (matchStr("/*"))
{
// Read until the end of the comment
for (;;)
{
char ch = readCh();
if (ch == '*' && matchCh('/'))
break;
}
continue;
}
// This isn't whitespace, stop
break;
}
}
/// Try and match a given character in the input
/// The character is consumed if matched
bool Input::matchCh(char ch)
{
if (peekCh() == ch)
{
readCh();
return true;
}
return false;
}
/// Try and match a given string in the input
/// The string is consumed if matched
bool Input::matchStr(const std::string& str)
{
if (peekStr(str))
{
for (size_t i = 0; i < str.length(); ++i)
readCh();
return true;
}
return false;
}
void LexicalAnalyzer::LexicalAnalyze(const string& srcCodeFilePath)
// an integrated automaton using if-else sentence
// according to current input symbol, a sub-automaton would be activated
{
FILE* fp = fopen("./test.cpp", "r");
char ch;
ch = fgetc(fp);
while(ch != EOF)
{
// cout << ch;
if(isalpha(ch) || ch == '_')
{
// cout << "will read id" << endl;
readID(fp, ch);
// cout << "read id ok" << endl;
}
else if(ch == '\'')
{
// cout << "will read character" << endl;
readCh(fp, ch);
// cout << "read character ok" << endl;
}
else if(ch == '\"')
{
// cout << "will read string" << endl;
readStr(fp, ch);
// cout << "read string ok" << endl;
}
else if(isdigit(ch))
{
// cout << "will read constant" << endl;
readConst(fp, ch);
// cout << "read constant ok" << endl;
}
else if(ch == ' ' || ch == '\t' || ch == '\n')
{
// cout << "will read space tab and newline" << endl;
readSpaceTabNewline(fp, ch);
// cout << "read space tab and newline ok" << endl;
}
else
{
// cout << "will read symbol" << endl;
readSymbol(fp, ch);
// cout << "read symbol ok" << endl;
}
}
// cout << endl;
fclose(fp);
}
