Padre::Document(3)

NAME
Padre::Document - Padre Document API

DESCRIPTION
The Padre::Document class provides a base class, default implementation and API documentation for document type support in Padre.

As an API, it allows Padre developers and plug-in authors to implement extended support for various document types in Padre, while ensuring that a naive default document implementation exists that allows Padre to provide basic support (syntax highlighting mainly) for many document types without the need to install extra modules unless you need the extra functionality.

  Document Type Registration
Padre uses MIME types as the fundamental identifier when working with documents. Files are typed at load-time based on file extension (with a simple heuristic fallback when opening files with no extension).

Many of the MIME types are unofficial X-style identifiers, but in cases without an official type, Padre will try to use the most popular identifier (based on research into the various language communities).

Each supported mime has a mapping to a Scintilla lexer (for syntax highlighting), and an optional mapping to the class that provides enhanced support for that document type.

Plug-ins that implement support for a document type provide a "registered_documents" method that the plug-in manager will call as needed.

Plug-in authors should not load the document classes in advance, they will be automatically loaded by Padre as needed.

Padre does not currently support opening non-text files.

  File to MIME type mapping
Padre has a built-in hash mapping the file extensions to MIME types. In certain cases (.t, .pl, .pm) Padre also looks in the content of the file to determine if the file is Perl 5 or Perl 6.

MIME types are mapped to lexers that provide the syntax highlighting.

MIME types are also mapped to modules that implement special features needed by that kind of a file type.

Plug-ins can add further mappings.

  Plan
Padre has a built-in mapping of file extension to either a single MIME type or function name. In order to determine the actual MIME type Padre checks this hash. If the key is a subroutine it is called and it should return the MIME type of the file.

The user has a way in the GUI to add more file extensions and map them to existing MIME types or functions. It is probably better to have a commonly used name along with the MIME type in that GUI instead of the MIME type only.

I wonder if we should allow the users (and or plug-in authors) to change the functions or to add new functions that will map file content to MIME type or if we should just tell them to patch Padre. What if they need it for some internal project?

A plug-in is able to add new supported MIME types. Padre should either check for collisions if a plug-in wants to provide an already supported MIME type or should allow multiple support modules with a way to select the current one. (Again I think we probably don't need this. People can just come and add the MIME types to Padre core.) (not yet implemented)

A plug-in can register zero or more modules that implement special features needed by certain MIME types. Every MIME type can have only one module that implements its features. Padre is checking if a MIME type already has a registered module and does not let to replace it. (Special features such as commenting out a few lines at once, auto-completion or refactoring tools).

Padre should check if the given MIME type is one that is in the supported MIME type list. (TO DO)

Each MIME type is mapped to one or more lexers that provide the syntax highlighting. Every MIME type has to be mapped to at least one lexer but it can be mapped to several lexers as well. The user is able to select the lexer for each MIME type. (For this each lexer should have a reasonable name too.) (TO DO)

Every plug-in should be able to add a list of lexers to the existing MIME types regardless if the plug-in also provides the class that implements the features of that MIME type. By default Padre supports the built-in syntax highlighting of Scintilla. Perl 5 currently has two PPI based syntax highlighter, Perl 6 can use the STD.pm or Rakudo/PGE for syntax highlighting but there are two plug-ins - Parrot and Kate - that can provide syntax highlighting to a wide range of MIME types.

"provided_highlighters()" returns a list of arrays like this:

    ['Module with a colorize function' => 'Human readable Name' => 'Long description']

"highlighting_mime_types()" returns a hash where the keys are module names listed in "provided_highlighters", the values are array references to MIME types:

    'Module::A' => [ mime-type-1, mime-type-2]

The user can change the MIME type mapping of individual files and Padre should remember this choice and allow the user to change it to another specific MIME type or to set it to "Default by extension".

METHODS

  new
  my $doc = Padre::Document->new(
      filename => $file,
  );

$file is optional and if given it will be loaded in the document. MIME type is defined by the "guess_mimetype" function.

  error
    $document->error( $msg );

Open an error dialog box with $msg as main text. There's only one OK button. No return value.

  load_file
    $doc->load_file;

Loads the current file.

Sets the Encoding bit using Encode::Guess and tries to figure out what kind of newlines are in the file. Defaults to "utf-8" if it could not figure out the encoding.

Returns true on success false on failure. Sets "$doc->errstr".

  autocomplete_matching_char
The first argument needs to be a reference to the editor this method should work on.

The second argument is expected to be a event reference to the event object which is the reason why the method was launched.

This method expects a hash as the third argument. If the last key typed by the user is a key in this hash, the value is automatically added and the cursor is set between key and value. Both key and value are expected to be ASCII codes.

Usually used for brackets and text signs like:

  $self->autocomplete_matching_char(
      $editor,
      $event,
      39  => 39,  # ' '
      40  => 41,  # ( )
  );

Returns 1 if something was added or 0 otherwise (if anybody cares about this).

  write
Writes the document to an arbitrary local file using the same semantics as when we do a full file save.

  reload
Reload the current file discarding changes in the editor.

Returns true on success false on failure. Error message will be in "$doc->errstr".

TO DO: In the future it should backup the changes in case the user regrets the action.

  text_get
  my $string = $document->text_get;

The "text_get" method returns the content of the document as a simple plain scalar string.

  text_length
  my $chars = $document->GetLength;

The "text_length" method returns the size of the document in characters.

Note that this is the character length of the document and not the byte size of the document. The byte size of the file when saved is likely to differ from the character size.

  text_like
  my $cool = $document->text_like( qr/(?:robot|ninja|pirate)/i );

The "text_like" method takes a regular expression and tests the document to see if it matches.

Returns true if the document matches the regular express, or false if not.

  text_set
  $document->text_set("This is an\nentirely new document");

The "text_set" method takes a content string and does a complete atomic replacement of the document with new and entirely different content.

It uses a simple and direct approach which is fast but is not aware of context such as the current cursor position and the undo buffer.

As a result, it is only appropriate for use when a document is being changed for new content that is completely and utterly different.

To change a document to a new version that is similar to the old one (such as when you are doing refactoring tasks) the alternative "text_replace" or ideally "text_delta" should be used instead.

  text_replace
  $document->text_replace("This is a\nmodified document");

The "text_replace" method takes content as a string and incrementally modifies the current document to look like the new content.

The logic for this process is done with a Padre::Delta object created using Algorithm::Diff and is run in the foreground. Because this blocks the entire IDE it is considered relatively slow and expensive, and is particularly bad for large documents.

But because it is by the most simple way of applying changes to a document and does not require locks or background tasks, this method has a role to play in early implementations of new logic.

Once functionality using "text_replace" has matured, you should consider moving it into a background task which emits a Padre::Delta and then use "text_delta" to apply the change to the editor in the foreground.

Returns true if changes were made to the current document, or false if the new document is identical to the existing one and no change was needed.

  text_delta
The "text_delta" method takes a single Padre::Delta object as a parameter and applies it to the current document.

Returns true if the document was changed, false if passed the null delta and no changes were needed, or "undef" if not passed a Padre::Delta.

  get_indentation_level_string
Calculates the string that should be used to indent a given number of levels for this document.

Takes the indentation level as an integer argument which defaults to one. Note that indenting to level 2 may be different from just concatenating the indentation string to level one twice due to tab compression.

  event_on_char
NOT IMPLEMENTED IN THE BASE CLASS

This method - if implemented - is called after any addition of a character to the current document. This enables document classes to aid the user in the editing process in various ways, e.g. by auto-pairing of brackets or by suggesting usable method names when method-call syntax is detected.

Parameters retrieved are the objects for the document, the editor, and the wxWidgets event.

Returns nothing.

Cf. "Padre::Document::Perl" for an example.

  event_on_context_menu
NOT IMPLEMENTED IN THE BASE CLASS

This method - if implemented - is called when a user triggers the context menu (either by right-click or the context menu key or Shift+F10) in an editor after the standard context menu was created and populated in the "Padre::Wx::Editor" class. By manipulating the menu document classes may provide the user with additional options.

Parameters retrieved are the objects for the document, the editor, the context menu ("Wx::Menu") and the event.

Returns nothing.

  event_on_left_up
NOT IMPLEMENTED IN THE BASE CLASS

This method - if implemented - is called when a user left-clicks in an editor. This can be used to implement context-sensitive actions if the user presses modifier keys while clicking.

Parameters retrieved are the objects for the document, the editor, and the event.

Returns nothing.

  project
  my $project = $document->project;

The "project" method is used to discover which project a document is part of. It uses a variety of methods to discover, scanning the file system if needed to "intuit" the location and type of project.

Returns a Padre::Project object for the project, or "undef" if the document is unsaved, anonymous, or not part of any type of project for some other reason.

  project_dir
  my $path = $document->project_dir;

The "project_dir" method behaves similarly to "project", but instead it returns a path to the root directory of the project for this document.

Returns a directory as a string, or '' if the document is unsaved, anonymous, or not part of any type of project for some other reason.

  guess_indentation_style
Automatically infer the indentation style of the document using Text::FindIndent.

Returns a hash reference containing the keys "use_tabs", "tabwidth", and "indentwidth". It is suitable for passing to "set_indendentation_style".

  guess_filename
  my $name = $document->guess_filename

When creating new code, one job that the editor should really be able to do for you without needing to be told is to work out where to save the file.

When called on a new unsaved file, this method attempts to guess what the name of the file should be based purely on the content of the file.

In the base implementation, this returns "undef" to indicate that the method cannot make a reasonable guess at the name of the file.

Your MIME type specific document subclass should implement any file name detection as it sees fit, returning the file name as a string.

  guess_subpath
  my $subpath = $document->guess_subpath;

When called on a new unsaved file, this method attempts to guess what the sub-path of the file should be inside of the current project, based purely on the content of the file.

In the base implementation, this returns a null list to indicate that the method cannot make a reasonable guess at the name of the file.

Your MIME type specific document subclass should implement any file name detection as it sees fit, returning the project-rooted sub-path as a list of directory names.

These directory names do not need to exist, they only represent intent.