1.3 Filter Mode Options

The options available in filter mode are listed below. Except as otherwise noted, all options are mutually exclusive. Ordinarily a given application will require certain fixed settings of these options and will not work properly if they are set inappropriately.

-r, --raw-output

Normally the result obtained by evaluating the function in the virtual code file must be a list of character strings, which is written as such to standard output. However, if this option is selected, the form of the result is unconstrained, and it will be written in a data file format that is not human readable but can be used by other applications. This option is incompatible with any other options except -u.

-c, --choice-of-output

When this option is used, the evaluation of the function given by the virtual machine code will be expected to yield a data structure from which avram will ascertain whether standard output should be written in text or raw data format. This option should be used only if application is aware of it. It is incompatible with any other options except -u.

-l, --line-map

Normally the entire contents of standard input up to EOF are loaded into memory and used as the argument to the function in the virtual code file. However, this option causes standard input to be read a line at a time, with the function applied individually to each line, and its result in each case written immediately to standard output. A given application either requires this option or does not, and will not work properly in the alternative. This option implies --force-text-input and is incompatible with any other option except -u.

-b, --byte-transducer

This option causes standard input to be read one character at a time, evaluating the function given by the virtual code file each time. The function is used as a state transition function that takes a state and input to a next state and output. The output is written concurrently with the input operations. A given application will not work properly with an inappropriate setting of this option. This option implies --force-text-input and is incompatible with any other option except -u.

-u, --unparameterized

Normally avram guesses whether to use filter mode or parameter mode depending on whether there are any parameters. Selecting this option forces it to operate in filter mode regardless. Any parameters that may appear on the command line after the virtual code file name are ignored. This option may be used in conjunction with any other filter mode option.