NAME
    create_vars   -- Create variables in a var_list
    free_vars	  -- Free variables in a var_list
    free_var_list -- Free memory used by nodes in var_list
    init_var_list -- Initialise a var_list
    make_var_list -- Create a var_list from an expression

SYNOPSIS

    int create_vars(vl);
    void free_vars(vl);
    void free_var_list(vl);
    #define init_var_list(vl);
    var_list *make_var_list(val, vl);

    var_list *vl; The variable list
    value val; The expression

RETURNS
    create_vars : TRUE if it succeeds, FALSE otherwise (no memory).

    make_var_list : returns vl, NULL if not enough memory (it then frees the
		    whole var_list).

FUNCTION
    These routines deal with var_lists: init_var_list() initialises the
    var_list (it must be called first), make_var_list() adds to vl all the
    variables in the expression val (as long as they aren't already there),
    free_var_list frees the memory used by the nodes in the list. You can
    then call create_vars, this creates all the variables in the
    var_list(by calling create_var_name). If it fails, none of the
    variables will have been created (so don't call free_vars !). Finally
    free_vars frees all the variables in a var_list (by calling
    free_var_name).

SEE ALSO
    create_var_name, free_var_name