// Process a triple quoted string, the leading """ of which has been seen, but
// not consumed
static token_t* triple_string(lexer_t* lexer)
{
consume_chars(lexer, 3); // Leading """
while(true)
{
if(is_eof(lexer))
return literal_doesnt_terminate(lexer);
char c = look(lexer);
if((c == '\"') && (lookn(lexer, 2) == '\"') && (lookn(lexer, 3) == '\"'))
{
consume_chars(lexer, 3);
// Triple strings can end with 3 or more "s. If there are more than 3
// the extra ones are part of the string contents
while(look(lexer) == '\"')
{
append_to_token(lexer, '\"');
consume_chars(lexer, 1);
}
normalise_string(lexer);
return make_token_with_text(lexer, TK_STRING);
}
consume_chars(lexer, 1);
append_to_token(lexer, c);
}
}
// Process a block comment the leading / * for which has been seen, but not
// consumed
static token_t* nested_comment(lexer_t* lexer)
{
consume_chars(lexer, 2); // Leading / *
size_t depth = 1;
while(depth > 0)
{
if(lexer->len <= 1)
{
lex_error(lexer, "Nested comment doesn't terminate");
lexer->ptr += lexer->len;
lexer->len = 0;
return make_token(lexer, TK_LEX_ERROR);
}
if(look(lexer) == '*' && lookn(lexer, 2) == '/')
{
consume_chars(lexer, 2);
depth--;
}
else if(look(lexer) == '/' && lookn(lexer, 2) == '*')
{
consume_chars(lexer, 2);
depth++;
}
else
{
consume_chars(lexer, 1);
}
}
lexer->newline = false;
return NULL;
}
// Process a slash, which has been seen, but not consumed
static token_t* slash(lexer_t* lexer)
{
if(lookn(lexer, 2) == '*')
return nested_comment(lexer);
if(lookn(lexer, 2) == '/')
return line_comment(lexer);
consume_chars(lexer, 1);
return make_token(lexer, TK_DIVIDE);
}
// Process a triple quoted string, the leading """ of which has been seen, but
// not consumed
static token_t* triple_string(lexer_t* lexer)
{
consume_chars(lexer, 3); // Leading """
while(true)
{
if(is_eof(lexer))
return literal_doesnt_terminate(lexer);
char c = look(lexer);
if((c == '\"') && (lookn(lexer, 2) == '\"') && (lookn(lexer, 3) == '\"'))
{
consume_chars(lexer, 3);
normalise_string(lexer);
return make_token_with_text(lexer, TK_STRING);
}
consume_chars(lexer, 1);
append_to_token(lexer, c);
}
}
// Process a string or character escape sequence, the leading \ of which has
// been seen but not consumed.
// Errors are reported at the start of the sequence (ie the \ ).
// Returns the escape value or <0 on error.
static int escape(lexer_t* lexer, bool unicode_allowed)
{
// Record the start position of the escape sequence for error reporting
const char* start = &lexer->source->m[lexer->ptr];
size_t line = lexer->line;
size_t pos = lexer->pos;
char c = lookn(lexer, 2);
consume_chars(lexer, 2);
int value = -2; // Default is 2 bad characters, \ and whatever follows it
int hex_digits = 0;
switch(c)
{
case 'a': value = 0x07; break;
case 'b': value = 0x08; break;
case 'e': value = 0x1B; break;
case 'f': value = 0x0C; break;
case 'n': value = 0x0A; break;
case 'r': value = 0x0D; break;
case 't': value = 0x09; break;
case 'v': value = 0x0B; break;
case '\"': value = 0x22; break;
case '\'': value = 0x27; break;
case '\\': value = 0x5C; break;
case '0': value = 0x00; break;
case 'x': hex_digits = 2; break;
case 'u':
if(unicode_allowed)
hex_digits = 4;
break;
case 'U':
if(unicode_allowed)
hex_digits = 6;
break;
}
if(hex_digits > 0)
{
value = read_hex_escape(lexer, hex_digits);
if(value < 0)
{
lex_error_at(lexer, line, pos,
"Invalid escape sequence \"%.*s\", %d hex digits required",
-value, start, hex_digits);
return -1;
}
if(value > 0x10FFFF)
{
lex_error_at(lexer, line, pos,
"Escape sequence \"%8s\" exceeds unicode range (0x10FFFF)", start);
return -1;
}
}
if(value < 0)
{
lex_error_at(lexer, line, pos, "Invalid escape sequence \"%.*s\"",
-value, start);
return -1;
}
return value;
}
