1Reply::Plugin(3) User Contributed Perl Documentation Reply::Plugin(3)
2
6 Reply::Plugin - base class for Reply plugins
7
9 version 0.42
10
12 package Reply::Plugin::Foo;
13 use strict;
14 use warnings;
15 use base 'Reply::Plugin';
17 # ...
19
21 A Reply plugin is an object which adds some functionality to a Reply
22 instance by implementing some specific methods which the Reply object
23 will call at various points during execution. Plugins may implement as
24 many callback methods as necessary to implement their functionality
25 (although the more callbacks a given plugin implements, the more likely
26 it is that the plugin may be more useful as multiple independent
27 plugins).
28 Callback methods have three potential calling conventions:
30 wrapped
32 Wrapped callbacks receive a coderef as their first argument (before
33 any arguments to the callback itself), and that coderef can be used
34 to call the next callback in the list (if more than one plugin
35 implements a given callback). In particular, this allows calling
36 the next plugin multiple times, or not at all if necessary. Wrapped
37 plugins should always call their coderef in list context. All
38 plugins listed below are wrapped plugins unless indicated
39 otherwise.
40 chained
42 Chained callbacks receive a list of arguments, and return a new
43 list of arguments which will be passed to the next plugin in the
44 chain. This allows each plugin a chance to modify a value before
45 it's actually used by the repl.
46 concatenate
48 Concatenate callbacks receive a list of arguments, and return a
49 list of response values. Each plugin that implements the given
50 callback will be called with the same arguments, and the results
51 will be concatenated together into a single list, which will be
52 returned. Callbacks for published messages are of this type.
53 CALLBACKS
55 prompt
56 Called to determine the prompt to use when reading the next line.
57 Takes no arguments, and returns a single string to use as the
58 prompt. The default implementation returns ">"
59 read_line
61 Called to actually read a line from the user. Takes no arguments,
62 and returns a single string. The default implementation uses the
63 "<>" operator to read a single line from "STDIN".
64 command_$name (chained)
66 If the line read from the user is of the form "#foo args...", then
67 plugins will be searched for a callback method named "command_foo".
68 This callback takes a single string containing the provided
69 arguments, and returns a new line to evaluate instead, if any.
70 mangle_line (chained)
72 Modifies the line read from the user before it's evaluated. Takes
73 the line as a string and returns the modified line.
74 compile
76 Compiles the string of Perl code into a coderef. Takes the line of
77 code as a string and a hash of extra parameters, and returns the
78 coderef to be executed. The default implementation uses
79 Eval::Closure to compile the given string.
80 The hash of extra parameters is passed directly to "eval_closure".
82 execute
84 Executes the coderef which has just been compiled. Takes the
85 coderef and a list of parameters to pass to it, and returns the
86 list of results returned by calling the coderef. The default
87 implementation just calls the coderef directly.
88 mangle_error (chained)
90 If the "compile" or "execute" callbacks throw an exception, this
91 callback will be called to modify the exception before it is passed
92 to "print_error". It receives the exception and returns the
93 modified exception.
94 print_error
96 If the "compile" or "execute" callbacks throw an exception, this
97 callback will be called to display it to the user. It receives the
98 exception and returns nothing. The default implementation just uses
99 "print" to print it to the screen.
100 mangle_result (chained)
102 This callback is used to modify the result of evaluating the line
103 of code before it is displayed. It receives the list of results and
104 returns a modified list of results.
105 print_result
107 This callback displays to the user the results of evaluating the
108 given line of code. It receives the list of results, and returns
109 nothing. The default implementation just uses "print" to print them
110 to the screen.
111 loop (chained)
113 This callback is called at the end of each evaluation. It receives
114 whether the repl has been requested to terminate so far, and
115 returns whether the repl should terminate.
116 Reply plugins can also communicate among each other via a pub/sub
118 mechanism. By calling the "publish" method, all plugins which respond
119 to the given message (implement a method of the given name) will have
120 that method called with the given arguments, and all of the responses
121 will be collected and returned. Some messages used by the default
122 plugins are:
123 tab_handler ($line)
125 Plugins can publish this message when they want to attempt tab
126 completion. Plugins that respond to this message should return a
127 list of potential completions of the line which is passed in.
128 lexical_environment
130 Plugins which wish to modify the lexical environment should do so
131 by implementing this message, which should return a hashref of
132 variable names (including sigils) to value references. There can be
133 more than one lexical environment (each maintained by a different
134 plugin), so plugins that wish to inspect the lexical environment
135 should do so by calling "$self->publish('lexical_environment')",
136 and then merging together all of the hashrefs which are returned.
137 package
139 Plugins which wish to modify the currently active package should do
140 so by implementing this message, which should return the name of
141 the current package. Then, to access the currently active package,
142 a plugin can call "($self->publish('package'))[-1]".
143 Your plugins, however, are not limited to these messages - you can use
145 whatever messages you want to communicate.
146
148 publish ($name, @args)
149 Publish a message to other plugins which respond to it. All loaded
150 plugins which implement a method named $name will have it called with
151 @args as the parameters. Returns a list of everything that each plugin
152 responded with.
153 commands
155 Returns the names of the "#" commands that this plugin implements. This
156 can be used in conjunction with "publish" -
157 "$plugin->publish('commands')" will return a list of all commands which
158 are available in the current Reply session.
159
161 Jesse Luehrs <doy@tozt.net>
162
164 This software is Copyright (c) 2016 by Jesse Luehrs.
165 This is free software, licensed under:
167 The MIT (X11) License
169perl v5.30.1 2020-01-30 Reply::Plugin(3)