static enum token
t_lex(char *s)
{
int num;
if (s == NULL) {
return EOI;
}
num = find_op(s);
if (((TOKEN_TYPE(num) == UNOP || TOKEN_TYPE(num) == BUNOP)
&& isunopoperand()) ||
(num == LPAREN && islparenoperand()) ||
(num == RPAREN && isrparenoperand()))
return OPERAND;
return num;
}
static int
primary(enum token n)
{
enum token nn;
int res;
if (n == EOI)
return 0; /* missing expression */
if (n == LPAREN) {
parenlevel++;
if ((nn = t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL)) ==
RPAREN) {
parenlevel--;
return 0; /* missing expression */
}
res = oexpr(nn);
if (t_lex(nargc > 0 ? (--nargc, *++t_wp) : NULL) != RPAREN)
syntax(NULL, "closing paren expected");
parenlevel--;
return res;
}
if (TOKEN_TYPE(n) == UNOP) {
/* unary expression */
if (--nargc == 0)
syntax(NULL, "argument expected"); /* impossible */
switch (n) {
case STREZ:
return strlen(*++t_wp) == 0;
case STRNZ:
return strlen(*++t_wp) != 0;
case FILTT:
return isatty(getn(*++t_wp));
default:
return filstat(*++t_wp, n);
}
}
nn = t_lex(nargc > 0 ? t_wp[1] : NULL);
if (TOKEN_TYPE(nn) == BINOP)
return binop(nn);
return strlen(*t_wp) > 0;
}
static int
islparenoperand(void)
{
char *s;
int num;
if (nargc == 1)
return 1;
s = *(t_wp + 1);
if (nargc == 2)
return parenlevel == 1 && strcmp(s, ")") == 0;
if (nargc != 3)
return 0;
num = find_op(s);
return TOKEN_TYPE(num) == BINOP;
}
static int
isunopoperand(void)
{
char *s;
char *t;
int num;
if (nargc == 1)
return 1;
s = *(t_wp + 1);
if (nargc == 2)
return parenlevel == 1 && strcmp(s, ")") == 0;
t = *(t_wp + 2);
num = find_op(s);
return TOKEN_TYPE(num) == BINOP &&
(parenlevel == 0 || t[0] != ')' || t[1] != '\0');
}
void CSGScanner :: ReadNext ()
{
char ch;
// scan whitespaces
do
{
scanin->get(ch);
//if (ch == '\n')
// linenum++;
// end of file reached
if (scanin->eof())
{
token = TOK_END;
return;
}
if (ch == '\n')
linenum++;
// skip comment line
if (ch == '#')
{
while (ch != '\n')
{
scanin->get(ch);
if (scanin->eof())
{
token = TOK_END;
return;
}
}
linenum++;
}
}
while (isspace(ch));
switch (ch)
{
case '(': case ')':
case '[': case ']':
case '-':
case '=': case ',': case ';':
{
token = TOKEN_TYPE (ch);
break;
}
default:
{
if (isdigit (ch) || ch == '.')
{
scanin->putback (ch);
(*scanin) >> num_value;
token = TOK_NUM;
return;
}
if (isalpha (ch))
{
string_value = string (1, ch);
scanin->get(ch);
while (isalnum(ch) || ch == '_')
{
string_value += ch;
scanin->get(ch);
}
scanin->putback (ch);
}
int nr = 0;
while (defkw[nr].kw)
{
if (string_value == defkw[nr].name)
{
token = defkw[nr].kw;
return;
}
nr++;
}
nr = 0;
while (defprim[nr].kw)
{
if (string_value == defprim[nr].name)
{
token = TOK_PRIMITIVE;
prim_token = defprim[nr].kw;
return;
}
nr++;
}
token = TOK_STRING;
}
}
