Directives

There are a number of directives that can be given to ISETL to modify its behavior.

On the command line,

- s

indicates silent mode. In silent mode, the header and all prompts are supressed. This is useful when using ISETL as a filter. This feature is not available on the Macintosh version.)

The rest of the directives are

!

commands.

  1. !quit

    – exit ISETL.

  2. !include < filename >

    – Replace

    < filename >

    with a file/pathname according to the rules of your operating system. ISETL will insert your file.

  3. !clear

    – throw away all input back to the last single prompt.

  4. !edit

    – edit all the input back to the last single prompt.

  5. !echo[on| off]

    – When on, all input is echoed. This is particularly useful when trying to find a syntax error in an

    !include

    file or input for a read. It is also useful for pedagogical purposes, as it can be used to interleave input and output.

  6. !memory

    – shows how much memory has been allocated.

  7. !memorynnn

    – increase the legal upper bound to

    nnn

    .

  8. !code[on| off]

    – When on, you get a pseudo-assembly listing for the program. Default is off.

  9. !trace[on| off]

    – When on, you get an execution trace, using the same notation as

    !code

    . When desperate, this can be used to watch the execution of your program. Really intended for debugging ISETL. Default is off.

  10. !ids

    – Lists all identifiers which have been defined.