1Demos(3) User Contributed Perl Documentation Demos(3)
2
6 PDL::Demos - PDL demo infrastructure
7
9 # in a demo, if text-orientated
10 package PDL::Demos::Blah;
11 sub info { ('blah', 'Longer description of demo') }
12 sub init { 'use PDL::Graphics::PGPLOT;' }
13 my @demo = (
14 [comment => "Welcome to the Blah demo"],
15 [act => <<'EOF'],
16 output "PDL can make n-dimensional sequences:\n";
17 output $x = sequence(2,3);
18 EOF
19 );
20 sub demo { @demo }
21 sub done { "# return things to previous state\n" }
22 # a GUI-orientated one
24 package PDL::Demos::GUIBlah;
25 use GUIBlah; # so demo won't show up in list if GUIBlah not installed
26 sub info { ('blahgui', 'GUIBlah demo') }
27 sub demo {[actnw => q|
28 # starting up the GUI demo app
29 |.__PACKAGE__.q|::run();
30 |]}
31 sub run { # this is just a convention, but a good one
32 # ...
33 }
34 # iterate a demo of your own module - call it PDL::Demos::(something)
36 make && perl -Mblib -S perldl # run "demo" and it will see your demo
37 # in a CLI or REPL
39 use PDL::Demos;
40 sub demo {
41 if (!$_[0]) {
42 require List::Util;
43 my @kw = sort grep $_ ne 'pdl', PDL::Demos->keywords;
44 my $maxlen = List::Util::max(map length, @kw);
45 print "Use:\n";
46 printf " demo %-${maxlen}s # %s\n", @$_[0,1] for map [PDL::Demos->info($_)], 'pdl', @kw;
47 return;
48 }
49 no strict;
50 PDL::Demos->init($_[0]);
51 $_->[0]->($_->[1]) for PDL::Demos->demo($_[0]);
52 PDL::Demos->done($_[0]);
53 }
54
56 Provides utilities to make demos for PDL modules.
57
59 list
60 Class method; goes through @INC finding all modules starting with
61 "PDL::Demos::" (with up to two "::"-separated words). Cached after
62 first run. Does not distinguish demo modules that did not load.
63 keywords
65 Returns the list of keywords (first element of "info" return-list) of
66 all found modules that loaded successfully and implement an "info"
67 method. Caches results.
68 info
70 Given a keyword, returns the result of calling "info" on the relevant
71 module plus the module name (three elements) or throws exception if
72 unknown keyword.
73 init
75 Given a keyword, "eval"s the result of calling "init" on the relevant
76 module if it has one, or throws exception if unknown keyword.
77 demo
79 Given a keyword, returns the result of calling "demo" on the relevant
80 module or throws exception if unknown keyword.
81 done
83 Given a keyword, "eval"s the result of calling "done" on the relevant
84 module if it has one, or throws exception if unknown keyword.
85
87 Each demo module must provide these class methods:
88 info
90 Return a two-element list: a single keyword (probably lower-case),
91 and a short description of the demo.
92 demo
94 Returns a list of array-refs of two elements: a function provided
95 by this module, and an argument for it.
96 init
98 Return a string which will be evaluated in the package running the
99 demo. Use this for "use" statements that import functions needed in
100 your demo.
101
103 These are all exported.
104 comment
106 Prints its argument, prompts user to press enter before returning.
107 output
109 Prints its argument (best for use in "actnw" etc).
110 actnw
112 Prints its argument with a separator, then evaluates it as Perl code
113 with "PDL" loaded. Doesn't prompt, so use this for e.g. GUI demos that
114 return when the user tells them to.
115 act
117 As above, but prompts before returning.
118
120 Copyright (C) 1998 Tuomas J. Lukka. Tweaks by Ed J for PDL 2.077,
121 2022.
122perl v5.36.0 2023-01-20 Demos(3)