Shell

Table of Contents

• Introduction
• How to invoke the shell
  • The Shell module
  • The -shell command line option
• How to interact with the shell
• Shell commands
  • @query
  • @move
  • @next
  • @prev
  • @features

Introduction

The AlvisNLP/ML Shell is an console that allows you to evaluate Element expressions interactively. The Shell is useful to explore the corpus annotations and to debug your plans.

How to invoke the shell

The Shell module

Add a module of class Shell in your plan at the point where you want to explore the corpus.

The -shell command line option

If you launch AlvisNLP/ML with the -shell option, then it will open the shell after the corpus has been processed by the whole plan.

How to interact with the shell

The shell will display a prompt (">", by default) and wait for a command. If you type an expression, then it will be evaluated and the result displayed. For example:

> documents

can produce the following output:

Document: 9795118
Document: 7797557
Document: 9353924
Document: 8419299
Document: 9826772
Document: 9701599
Document: 9852010
Document: 9786190
Document: 9988713
Document: 9671823
Document: 9805371
Document: 9811636
Document: 100614
Document: 9680198
...

Each line represents an element of the result set and indicates the type of the element (Document) and its identifier. The Shell may evaluate any type of expression:

> number(documents)

may produce the following output:

375.0

After the Shell has evaluated an expression and printed the result, it is ready for the next one...
In order to leave the shell, type Ctrl-D.

Shell commands

The general syntax for the Shell is the following:

> [@command] [expression]

@command is a Shell command, when it is omitted, then it is an expression query by default.
expression is the command's operand. The operand is optional or mandatory depending on the command.

@query

This command evaluates expression with the current context element and displays the result. AlvisNLP/ML tries its best to guess the most sensible evaluation type.
The expression operand is mandatory.

@move

This command evaluates expression as a list of elements and uses the first one as the context element for the following commands. When the shell is opened, the default context element is the corpus. In order to get back at the corpus, simply type:

> @move corpus

Subsequent @next and @prev commands will navigate along the elements of the result set.
The expression operand is mandatory.

@next

For the following commands, the shell uses the next element from the result of the last @move command as the context element.
This command accepts no operand.

@prev

For the following commands, the shell uses the previous element from the result of the last @move command as the context element.
This command accepts no operand.

@features

This command evaluates expression as a list of elements and prints all features of each one.
If expression is omitted, then the shell prints all features of the current context element.