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Diffstat (limited to 'runtime/doc/develop.txt')
| -rw-r--r-- | runtime/doc/develop.txt | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/runtime/doc/develop.txt b/runtime/doc/develop.txt index 658de0dce9..4013544311 100644 --- a/runtime/doc/develop.txt +++ b/runtime/doc/develop.txt @@ -122,7 +122,7 @@ include the kitchen sink... but you can use it for plumbing." ============================================================================== 2. Design decisions *design-decisions* -Naming the window +Window The word "window" is commonly used for several things: A window on the screen, the xterm window, a window inside Vim to view a buffer. @@ -137,6 +137,51 @@ window View on a buffer. There can be several windows in Vim, together with the command line, menubar, toolbar, etc. they fit in the shell. + +Providers *dev-provider* + +A goal of Nvim is to allow extension of the editor without special knowledge +in the core. But some Vim components are too tightly coupled; in those cases +a "provider" hook is exposed. + +Consider two examples of integration with external systems that are +implemented in Vim and are now decoupled from Nvim core as providers: + +1. In the Vim source code, clipboard logic accounts for more than 1k lines of + C source code (ui.c), to perform two tasks that are now accomplished with + shell commands such as xclip or pbcopy/pbpaste. + +2. Python scripting support: Vim has three files dedicated to embedding the + Python interpreter: if_python.c, if_python3.c and if_py_both.h. Together + these files sum about 9.5k lines of C source code. In contrast, Nvim Python + scripting is performed by an external host process implemented in ~2k lines + of Python. + +Ideally we could implement Python and clipboard integration in pure vimscript +and without touching the C code. But this is infeasible without compromising +backwards compatibility with Vim; that's where providers help. + +The provider framework helps call vimscript from C. It is composed of two +functions in eval.c: + +- eval_call_provider(name, method, arguments): calls provider#(name)#Call + with the method and arguments. +- eval_has_provider(name): Checks if a provider is implemented. Returns true + if the provider#(name)#Call function is implemented. Called by |has()| + (vimscript) to check if features are available. + +The provider#(name)#Call function implements integration with an external +system, because calling shell commands and |rpc| clients are easier to work +with in vimscript. + +For example, the Python provider is implemented by the +autoload/provider/python.vim script; the provider#python#Call function is only +defined if a valid external Python host is found. That works well with the +`has('python')` expression (normally used by Python plugins) because if the +Python host isn't installed then the plugin will "think" it is running in +a Vim compiled without the |+python| feature. + + RPC API API client remote plugin |