Function process_backslash_command

src/bin/pgbench/pgbench.c:4882–5089

* Parse a backslash command; return a Command struct, or NULL if comment * * At call, we have scanned only the initial backslash. */

 * At call, we have scanned only the initial backslash.
 */
static Command *
process_backslash_command(PsqlScanState sstate, const char *source)
{
	Command    *my_command;
	PQExpBufferData word_buf;
	int			word_offset;
	int			offsets[MAX_ARGS];	/* offsets of argument words */
	int			start_offset;
	int			lineno;
	int			j;

	initPQExpBuffer(&word_buf);

	/* Remember location of the backslash */
	start_offset = expr_scanner_offset(sstate) - 1;
	lineno = expr_scanner_get_lineno(sstate, start_offset);

	/* Collect first word of command */
	if (!expr_lex_one_word(sstate, &word_buf, &word_offset))
	{
		termPQExpBuffer(&word_buf);
		return NULL;
	}

	/* Allocate and initialize Command structure */
	my_command = (Command *) pg_malloc0(sizeof(Command));
	my_command->type = META_COMMAND;
	my_command->argc = 0;
	initSimpleStats(&my_command->stats);

	/* Save first word (command name) */
	j = 0;
	offsets[j] = word_offset;
	my_command->argv[j++] = pg_strdup(word_buf.data);
	my_command->argc++;

	/* ... and convert it to enum form */
	my_command->meta = getMetaCommand(my_command->argv[0]);

	if (my_command->meta == META_SET ||
		my_command->meta == META_IF ||
		my_command->meta == META_ELIF)
	{
		yyscan_t	yyscanner;

		/* For \set, collect var name */
		if (my_command->meta == META_SET)
		{
			if (!expr_lex_one_word(sstate, &word_buf, &word_offset))
				syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
							 "missing argument", NULL, -1);

			offsets[j] = word_offset;
			my_command->argv[j++] = pg_strdup(word_buf.data);
			my_command->argc++;
		}

		/* then for all parse the expression */