For a quick overview of how we've improved the editor in PTVS 2.0, please watch the video:
When developing, most of your time is spent in the text editor. Python Tools provides a rich editor with functionality to help you be more productive, such as syntax highlighting, identifier and member completion, signature help, method overrides, and search
and navigation. A background analysis engine uses type inference and whole-program analysis to determine the possible types of each variable, ensuring that the information provided is accurate and up to date.
This section describes the editor features in detail.
IntelliSense exposes results of analyzing your programs in three different forms: completions, signature help, and quick info.
Before You Begin
To improve performance, a lot of our IntelliSense features depend on a completion database. This database is automatically generated in the background for each version of Python you have, and contains all the information about its standard library
and any other installed packages. You can see the current state of the database in the Python Enviroments list (Ctrl+K, ` - Control + K, backtick):
Databases may need refreshing if you add, remove or update packages. You can click the "Refresh DB" button at any time to start refreshing. You can close Visual Studio or continue to work while refreshing, but be aware that this is a CPU and memory
intensive process that may take over an hour. In general, a full refresh will only occur once; subsequent refreshes will be much faster.
Completions are shown as a list of words that may be entered at your current location. The lists are based on the context and are filtered to avoid showing options that are incorrect or distracting. Completions can be shown at any time by pressing Ctrl+J
or Ctrl+Space, or may be triggered automatically by certain commands (such as import) or operators (such as a period/full stop).
(To prevent completions from appearing automatically, disable Tools -> Options -> Text Editor -> Python -> Advanced -> Auto list members. You can still manually show completions by pressing Ctrl+J or Ctrl+Space.)
With a list open, you can search for the completion you want using the arrow keys, the mouse, or by continuing to type. As you type more letters, the list is further filtered to show likely completions. This filtering is smart and will let you take shortcuts
- Typing letters that are not at the start of the name, such as 'parse' to find 'argparse'
- Typing only letters that are at the start of words, such as 'abc' to find 'AbstractBaseClass' or 'air' to find 'as_integer_ratio'
- Skipping letters, such as 'b64' to find 'base64'
(To stop filtering the list, disable Tools -> Options -> Text Editor -> Python -> Advanced -> Filter list based on search string.)
Member completions are shown automatically when you type a period after a variable or value, and will display the methods and attributes of the potential types. If a variable could be more than one type, the list will include all possibilities from all types,
with extra information to indicate which types support each completion. Where a completion is supported by all possible types, it is shown without annotation.
(To only show completions that are supported by all possible types, enable Tools -> Options -> Text Editor -> Python -> Advanced -> Member completion displays intersection of members.)
By default, members beginning and ending with a double underscore are not shown. In general, these members should not be accessed directly, but if you need one, typing the leading double underscore will add these completions into the list.
(To always show double-underscore members, disable Tools -> Options -> Text Editor -> Python -> General -> Hide advanced members.)
The 'import' and 'from...import' statements display a list of modules that can be imported and, in the case of 'from...import', the members that can be imported from the specified module.
The 'raise' and 'except' statements will display lists of classes likely to be error types. These may not include all user defined exceptions, but will help you find suitable built-in exceptions quickly.
The '@' symbol is used to start a decorator. After typing one of these, a list containing 'classmethod', 'staticmethod' and 'property' will appear. At present, these are the only decorators that will be shown in this list.
Signature help is displayed when writing a function call, and includes any documentation and parameter information that is available. The amount of information displayed typically depends on how much is written in the documentation strings, but will include
any default values. Signature help appears automatically after typing the '(' in a function call, and can be displayed at any time by pressing Ctrl+Shift+Space inside a function call.
(To stop automatically showing signature help, disable Tools -> Options -> Text Editor -> Python -> General -> Parameter information. You can still manually display signature help by pressing Ctrl+Shift+Space.)
Quick Info is a tooltip that is displayed when you hover the mouse over an identifier. Depending on the identifier, it may display the potential values or types, any available documentation, return types and definition locations.
Semantic Colorization uses information from code analysis to change the colors of variable names. For example, variables that refer to modules or classes may be shown in a different color to functions or other values. Parameter names may appear in a different
color to local or global variables.
(Note that, by default, functions are not shown in bold.)
To customize the colors used, modify the Python entries in Tools -> Options -> Environment -> Fonts and Colors.
(To disable semantic colorization, disable Tools -> Options -> Text Editor -> Python -> Advanced -> Color names based on types.)
There are four ways to utilize the program analysis to help you navigate your code. These are the navigation bar, Go To Definition, Navigate To and Find All References.
The navigation bar is displayed at the top of each editor window and includes a two-level list of definitions. The left dropdown contains top level class and function definitions in the current file, while the right dropdown has a list of definitions within
the scope shown in the left. As you move around in the editor, these will update to show your current context, and you can also select an entry from these lists to jump directly to in.
(To show or hide the navigation bar, enable or disable Tools -> Options -> Text Editor -> Python -> General -> Navigation Bar.)
Navigate To can be displayed at any time by selecting the Edit -> Navigate To command or pressing Ctrl+Comma. A search box is provided where you can type any name to see a list of possible matches in your project. The same search is used as for completions,
and so partial matches will also be displayed. Double-clicking any name, or selecting with arrow keys and Enter, will navigate to the definition of that item.
Go To Definition
Go To Definition is invoked through the context menu of an identifier or by pressing F12, and will open the file containing the definition of the currently selected identifier. This works for most class, function, and variable references in your projects
and external libraries, provided source code has been found by the analyzer. If you are unable to go to a definition, it is likely that it was defined in a compiled file and there is no Python source file.
Find All References
Find All References is also invoked through the context menu or by pressing Shift+F12. It will display a list of all references to the selected symbol that were found by the analyzer, including definitions, import, accesses, and assignments. Double-clicking
on any item in this list will navigate to its location.
The Object Browser
When a project is loaded, Python Tools supports using the Object Browser for viewing classes defined in each module and the functions defined in those classes. The left hand pane of the Object Browser enables you to view all of the modules defined and drill
down into them. As you do so, the right hand side updates to reflect the current class you are browsing, and the bottom right hand pane will show you any information about the method currently selected on the right hand side.