read_options

(tmp_for_tar/vrml.doc/read_options.m)

Help text

 read_options is a script that can be called to read options from
 within a function. Variables in the function's namespace, with same
 name as the options will be set. read_options stops reading options
 as soon as it reads an argument that it does not recognize.

 nargin   : Should be set to the number of remaining arguments.

 opt0     : A single-space-separated string of boolean options. Should
            be padded with a single space at both extremities.
             Default is " ".

 opt1     : String of options taking one argument. Default is " ".

 filename : Name of the function, for verbose output or griping.
            Default is "unknown_func"

 verbose  : in {0,1} : be more or less verbose. Default is 0.

 opt_quiet: in {0,1} : If set, read_options will gripe when it
            encounters an unknown option. Otherwise, it just returns

 Also,  read_options  sets some variables that can be accessed from
 the calling function :

 last_option_name : The name of the last option name, OR whatever
                    unrecognized argument that caused read_options to
                    stop reading the arguments (if any).

 last_option_value: The value of the last option taking a single
                    argument (if any).

 option_number    : The number of arguments that have been read.

 read_options assumes that a script called from a function is executed
 as if its code was written within the function body. (like a #define
 in C). I don't think this feature is documented in octave, so it
 might stop working on some versions of octave. Works with 2.1.19.

 Last modified: December 2000

Cross-Reference Information

sayif        tmp_for_tar/vrml.doc/sayif.m

Listing of file tmp_for_tar/vrml.doc/read_options.m

## read_options is a script that can be called to read options from
## within a function. Variables in the function's namespace, with same
## name as the options will be set. read_options stops reading options
## as soon as it reads an argument that it does not recognize.
##
## nargin   : Should be set to the number of remaining arguments.
##
## opt0     : A single-space-separated string of boolean options. Should
##            be padded with a single space at both extremities.
##             Default is " ".
##
## opt1     : String of options taking one argument. Default is " ".
##
## filename : Name of the function, for verbose output or griping.
##            Default is "unknown_func"
##
## verbose  : in {0,1} : be more or less verbose. Default is 0.
##
## opt_quiet: in {0,1} : If set, read_options will gripe when it
##            encounters an unknown option. Otherwise, it just returns
##
## Also,  read_options  sets some variables that can be accessed from
## the calling function :
##
## last_option_name : The name of the last option name, OR whatever
##                    unrecognized argument that caused read_options to
##                    stop reading the arguments (if any).
##
## last_option_value: The value of the last option taking a single
##                    argument (if any).
## 
## option_number    : The number of arguments that have been read.
##
## read_options assumes that a script called from a function is executed
## as if its code was written within the function body. (like a #define
## in C). I don't think this feature is documented in octave, so it
## might stop working on some versions of octave. Works with 2.1.19.


## Author:        Etienne Grossmann  <etienne@isr.ist.utl.pt>
## Last modified: December 2000

if exist("filename","var")!=1  , filename="unkown_func" ; end
if exist("verbose","var")!=1   , verbose=0 ; end
if exist("opt0","var")!=1      , opt0=" "  ; end
if exist("opt1","var")!=1      , opt1=" "  ; end
if exist("opt_quiet","var")!=1 , opt_quiet=0  ; end

## opt0 
## opt1
## Commented 2000/08/13 ... break anything?
## va_start() ;
nargin_orig = nargin ;
option_number = 0 ;
## igncnt = 0 ;
while nargin>0 ,
  last_option_name = va_arg() ;
  ## opt0
  nargin-- ;
  option_number++ ;
  if ! isstr(last_option_name) ,
    if ! opt_quiet ,
      printf("%s : Non-string option : \n",filename) ;
      keyboard
    else
      if verbose,
	printf("read_options : ignoring non-string option number %d\n",\
	       option_number) ;
	## last_option_name 
      end
    end
    ## ignopt(++igncnt) = option_number ;
    ## if opt_quit_early, break ; end
    break ;
  end
  read_options_foo = [" ",last_option_name," "] ;
  ## keyboard
  if index(opt1,read_options_foo) ,
    
    last_option_value = va_arg() ;		#nargin-- ;
    ## last_option_value
    nargin-- ;
    option_number++ ;
    eval([last_option_name,"=last_option_value;"]) ;

    sayif(verbose ,"%s : Read option : %s.\n",filename,last_option_name) ;

  elseif index(opt0,read_options_foo) ,
    eval([last_option_name,"=1;"]) ;
    sayif(verbose ,"%s : Read boolean option : %s\n",filename,last_option_name) ;

  else
    if ! opt_quiet ,
      printf("%s : Unknown option : %s\n",filename,last_option_name) ;
      keyboard
    else
      if verbose,
	printf("read_options : ignoring option number %d, '%s'\n",\
	       option_number,last_option_name) ;
	last_option_name 
      end

    end
    ## ignopt(++igncnt) = option_number ;
    ## if opt_quit_early, break ; end
    break
  end
end