I tried to rewrite the example given in the page
http://www.fifi.org/doc/libgtk1.2-doc/faq-html/gtkfaq-8.html
so that it can read from a file, but its not.
The code that i tried is:
#include <glib.h>
/* some test text to be fed into the scanner */
/*static const gchar *test_text =
( "ping = 5;\n"
"/ * slide in some \n"
" * comments, just for the\n"
" * fun of it \n"
" * /\n"
"zonk = 0.7;\n"
"pong = -6; \n"
"\n"
"# the next value is a float\n"
"# redefine ping\n"
"ping = - 0.5;\n" );
*/
/* define enumeration values to be returned for specific symbols */
enum {
SYMBOL_PING = G_TOKEN_LAST + 1,
SYMBOL_PONG = G_TOKEN_LAST + 2,
SYMBOL_ZONK = G_TOKEN_LAST + 3
};
/* symbol array */
static const struct {
gchar *symbol_name;
guint symbol_token;
} symbols[] = {
{ "Author", SYMBOL_PING, },
{ "Title", SYMBOL_PONG, },
{ "zonk", SYMBOL_ZONK, },
{ NULL, 0, },
}, *symbol_p = symbols;
static gfloat ping = 0;
static gfloat pong = 0;
static gfloat zonk = 0;
static guint
parse_symbol (GScanner *scanner)
{
guint symbol;
gboolean negate = FALSE;
/* expect a valid symbol */
g_scanner_get_next_token (scanner);
symbol = scanner->token;
if (symbol < SYMBOL_PING ||
symbol > SYMBOL_ZONK)
return G_TOKEN_SYMBOL;
/* expect '=' */
g_scanner_get_next_token (scanner);
if (scanner->token != '=')
return '=';
/* feature optional '-' */
g_scanner_peek_next_token (scanner);
if (scanner->next_token == '-')
{
g_scanner_get_next_token (scanner);
negate = !negate;
}
/* expect a float (ints are converted to floats on the fly) */
g_scanner_get_next_token (scanner);
if (scanner->token != G_TOKEN_FLOAT)
return G_TOKEN_FLOAT;
/* make sure the next token is a ';' */
if (g_scanner_peek_next_token (scanner) != ';')
{
/* not so, eat up the non-semicolon and error out */
g_scanner_get_next_token (scanner);
return ';';
}
/* assign value, eat the semicolon and exit successfully */
switch (symbol)
{
case SYMBOL_PING:
ping = negate ? - scanner->value.v_float : scanner->value.v_float;
break;
case SYMBOL_PONG:
pong = negate ? - scanner->value.v_float : scanner->value.v_float;
break;
case SYMBOL_ZONK:
zonk = negate ? - scanner->value.v_float : scanner->value.v_float;
break;
}
g_scanner_get_next_token (scanner);
return G_TOKEN_NONE;
}
int
main (int argc, char *argv[])
{
GScanner *scanner;
guint expected_token;
scanner = g_scanner_new (NULL);
/* adjust lexing behaviour to suit our needs
*/
/* convert non-floats (octal values, hex values...) to G_TOKEN_INT */
scanner->config->numbers_2_int = TRUE;
/* convert G_TOKEN_INT to G_TOKEN_FLOAT */
scanner->config->int_2_float = TRUE;
/* don't return G_TOKEN_SYMBOL, but the symbol's value */
scanner->config->symbol_2_token = TRUE;
/* load symbols into the scanner */
while (symbol_p->symbol_name)
{
g_scanner_add_symbol (scanner,
symbol_p->symbol_name,
GINT_TO_POINTER (symbol_p->symbol_token));
symbol_p++;
}
gint file=1;
file=g_open("trial.bib", "r");
/* feed in the text */
g_scanner_input_file (scanner, file);
/* give the error handler an idea on how the input is named */
// scanner->input_name = "test text";
/* scanning loop, we parse the input until its end is reached,
* the scanner encountered a lexing error, or our sub routine came
* across invalid syntax
*/
do
{
expected_token = parse_symbol (scanner);
g_scanner_peek_next_token (scanner);
}
while (expected_token == G_TOKEN_NONE &&
scanner->next_token != G_TOKEN_EOF &&
scanner->next_token != G_TOKEN_ERROR);
/* give an error message upon syntax errors */
// if (expected_token != G_TOKEN_NONE)
// g_scanner_unexp_token (scanner, expected_token, NULL, "symbol",
NULL, NULL, TRUE);
/* finsish parsing */
g_scanner_destroy (scanner);
/* print results */
g_print ("ping: %s\n", ping);
g_print ("pong: %s\n", pong);
g_print ("zonk: %f\n", zonk);
return 0;
}
what is error in it?
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