LispVal* parse_string(FILE* f)
{
int length = 0;
char data[4096];
char c = peek(f);
if (c != '"')
return NULL;
c = get_peek(f);
while ((c != '"') && (!feof(f))) {
data[length] = c;
length++;
c = get_peek(f);
}
fgetc(f);
return lisp_val_string(length, data);
}
LispVal* parse_atom(FILE* f)
{
int length = 0;
char data[100];
char c = peek(f);
while (isalpha(c) && (!feof(f))) {
data[length] = c;
length++;
c = get_peek(f);
}
return lisp_val_atom(length, data);
}
LispVal* parse_number(FILE* f)
{
int num = 0;
char c = peek(f);
if (!isdigit(c))
return NULL;
while (isdigit(c)) {
num = (num*10) + (c-'0');
c = get_peek(f);
}
return lisp_val_num(num);
}
void eat_space(FILE* f)
{
char c = peek(f);
while (isspace(c))
c = get_peek(f);
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// class CTokenizer next_var_token method
// get a var token, and return it's type
// Input:
// none
// Output:
// none
// Return:
// enum var_token_type
//
int CTokenizer::next_var_token( bool is_key )
{
signed char ch;
int len = 0;
// skim over space if exist
if ( !m_nPrevChar )
{
skim_over_space(ch);
}
else
{
ch = m_nPrevChar;
m_nPrevChar = 0;
}
if ( ch == '[' )return VT_LSQR;
if ( ch == ':' )return VT_COLON;
if ( ch == ']' )return VT_RSQR;
// is this a decimal number, begin with 1~9
// sequence of digits
if ( ch <= '9' && ch >= '0')
{
do
{
put_char( ch, len );
ch = get_char();
if ( ch <= ' ' || ch == ':' || ch == ']') // the legal postfix of decimal number
{
m_nPrevChar = ch > ' ' ? ch : 0; // record the character as prev char in next var token
m_strTokenWord[len] = 0; // put end character into token word
m_nTokenLen = len; // get the length of token
return VT_DECIMAL;
}
}
while ( ch <= '9' && ch >= '0' );
return VT_NONE; // illegal postfix of decimal number
}
// is this an identifier or keyword,
// begin with letters or underscore characters(_)
// any sequence of letters, digits, dollars($) and underscore characters(_)
signed char ch2;
do
{
put_char( ch, len );
if ( (ch2 = get_peek()) == '[' )
{
m_nPrevChar = get_char();
break;
}
else
ch = get_char();
} while ( ch > ' ' );
m_strTokenWord[len] = 0;
if ( !is_key )
{
m_nTokenLen = len;
return VT_IDENTIFER;
}
int index = map_var_tokens( m_strTokenWord );
return index < NUM_VAR_TOKENS ? index : VT_NONE;
}
