“转到定义”和“转到参考”如何在 Python 的 vscode 中工作？

Question

The vscode will record all functions, classes, variables in a table? Or How does vscode can find definitions and references?

I want to know how VScode build this "Go To Definition" function?

Answer 1

Go to Definition:

If a language supports it, you can go to the definition of a symbol by pressing F12.

If you press Ctrl and hover over a symbol, a preview of the declaration will appear:

Tip: You can jump to the definition with Ctrl+Click or open the definition to the side with Ctrl+Alt+Click.

Go to Type Definition:

Some languages also support jumping to the type definition of a symbol by running the Go to Type Definition command from either the editor context menu or the Command Palette. This will take you to the definition of the type of a symbol. The command editor.action.goToTypeDefinition is not bound to a keyboard shortcut by default but you can add your own custom keybinding.

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Answer 2

This is a very complicated process and there is a ton of research on software engineering related to this area. Most IDEs/Extensions usually do a best-effort job, and that is good enough for various use cases. It also helps if one follows a widely used build system, and sticks to widely accepted code organization.

Finding definition of a call is a complicated process and usually involve building AST (Abstract Syntax Tree) of the program and finding where a function is defined. There are two important consideration:

1. type system of the language
2. organization of code around the build system

For (mostly) statically typed languages like C/C++ etc. finding the function declaration is not too difficult but finding definition usually involves finding where the source file (.c/.cpp) file is? Without the knowledge of build system (cmake, qmake) it is very difficult and hence most IDEs have hard time supporting it.

For languages like rust, where it is customary to follow a rigid system of code organization, simple grepping with some type information is sufficient to get most of the function definitions.

For languages with dynamic type (Python, JavaScript), it is very hard to find the right definition and IDEs/Extensions usually support a well known coding style and module system. TLDR: It helps to follow the crowd in this case. In my experience, PyCharm does a very good job of finding definition of a function invocation.