Function valid_variable_name

src/bin/psql/variables.c:21–41

* Check whether a variable's name is allowed. * * We allow any non-ASCII character, as well as ASCII letters, digits, and * underscore. Keep this in sync with the definition of variable_char in * psqlscan.l and psqlscanslash.l. */

 * psqlscan.l and psqlscanslash.l.
 */
static bool
valid_variable_name(const char *name)
{
	const unsigned char *ptr = (const unsigned char *) name;

	/* Mustn't be zero-length */
	if (*ptr == '\0')
		return false;

	while (*ptr)
	{
		if (IS_HIGHBIT_SET(*ptr) ||
			strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
				   "_0123456789", *ptr) != NULL)
			ptr++;
		else
			return false;
	}

	return true;
}

/*
 * A "variable space" is represented by an otherwise-unused struct _variable