NAME

App::Dochazka::CLI::Parser - Parser module

PACKAGE VARIABLES AND EXPORTS

generate_semantic_tree

Populate the $semantic_tree package variable.

lookup_command

parse

Parse the command string entered by the user.

possible_words

Given a state expressed as a stack of tokens, return list of possible tokens.

process_command

Given a command string, process it (by parsing, calling the handler, etc.) and return the result.

$semantic_tree

The semantic tree is a traversable tree representation of the CLI commands, i.e. the keys of the dispatch map $App::Dochazka::CLI::CommandMap::dispatch_map

FUNCTIONS

generate_semantic_tree

Generate the semantic context tree.

The set of keys of %$dispatch_map contains all the possible commands, each expressed as a sequence of tokens. The semantic context tree is generated from the dispatch map keys. Each node of the tree represents a possible token and the set of nodes at depth n of the tree is the set of possible tokens in the nth position within the command.

Taking, for example, a dispatch map consisting of the following two commands:

ABE BABEL CAROL
DALE EARL JENSEN PARLOR
DALE TWIT

The semantic tree would be:

(root)
|
+-----------+
|           |
ABE        DALE
|           |
|           +------+
|           |      |
BABEL      EARL   TWIT
|           |
CAROL      JENSEN
            |
           PARLOR

The point of this exercise is to facilitate command completion. If two a single token ABE has been entered by the user and <TAB> is pressed, finding out that BABEL is the only possible command in this position is a simple matter of traversing the above semantic tree. (And this is exactly what is done by the possible_words routine in App::Dochazka::CLI::Parser.)

This routine takes an optional argument which, if provided, is assumed to be a reference to a dispatch map. In the absence of this argument, the $dispatch_map package variable (initialized above) is used.

For this and more examples, see t/parser/semantic_tree.t.

look_up_command

Given a normalized command string such as "GET BUGREPORT", look it up in the dispatch map and return the corresponding coderef, or nothing if the lookup fails.

parse

Parse command string entered by the user. Takes the command string, and returns:

$nc

The normalized command - suitable for lookup via look_up_command

$ts

The token stack - a reference to the list of normalized tokens

$th

The token hash - a hash where the keys are the normalized tokens and the values are the raw values extracted from the command string. Whatever is left after command string parsing completes will be placed in the '_REMAINDER' key.

possible_words

Given a token stack, return the list of possible tokens.

process_command

Given a command entered by the user, process it and return the result.