parser(1)		      Grass User's Manual		     parser(1)



NNAAMMEE
       GGRRAASSSS  ppaarrsseerr  iinntteerrffaaccee   -  A set of GRASS routines that standardizes
       GRASS commands.

DDEESSCCRRIIPPTTIIOONN
       A set of routines in GRASS provides a mechanism for command-line  pars-
       ing.  The  routines standardize commands that expect command-line argu-
       ments.  When a user is familiar with the general form  of  command-line
       input  as  defined by the parser, it simplifies the necessity of remem-
       bering (or at least guessing) required command-line arguments  for  any
       GRASS command.


       The parser behaves in one of three ways:

	      If no command-line arguments are entered by the user, the parser
	      searches for an interactive version of the  command.  If	it  is
	      found, control is passed over to this interactive version. If it
	      is not found, the parser prompts the user for programmer-defined
	      options  and flags. This prompting conforms to the same standard
	      for every GRASS command that uses the parser routines.



	      If command-line arguments are entered but do not include all the
	      options  and  flags  that the programmer has defined as required
	      arguments, three things happen:

	      the parser passes an error message to the user indicating  which
	      required	options  and/or  flags	were missing from the command-
	      line,

	      then the parser displays a complete usage message for that  com-
	      mand, and finally

	       the parser cancels execution of the command.




	      If  all  necessary  options and flags are entered on the command
	      line by the user, the parser executes the command with the given
	      options and flags.



       _T_h_i_s  _p_a_g_e _w_a_s _d_e_r_i_v_e_d _f_r_o_m _t_h_e GRASS 4.1 Programmer's Manual, Command-
       Line Parsing, _w_h_i_c_h _o_f_f_e_r_s _d_e_t_a_i_l_e_d _i_n_f_o_r_m_a_t_i_o_n _a_b_o_u_t _t_h_e _G_R_A_S_S _p_a_r_s_i_n_g
       _r_o_u_t_i_n_e_s_.

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_4 _$



GRASS 5.0							     parser(1)
