Initial version

6 files changed, 385 insertions, 118 deletions

diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..7807837
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,23 @@
+Copyright 2010 Ton van den Heuvel. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
diff --git a/README.md b/README.md
index 70dcc7f..5ce7b10 100644
--- a/README.md
+++ b/README.md
@@ -1,39 +1,78 @@
-# NVIM Buffer Browser Navigation
+# NVIM Buffer Browse 
 
 `:b#` on steroids. Browse your buffers like you browse history in a browser.
 
 ## Motivation
 
 While `:bnext` and `:bprev` allows you to browse between buffers, it is not
-very intuitive. Oftentimes I would jump to definitions, a different file
-through netrw, an org file and then when using bprev I would end up in a
-completely different file, because buffers are ordered by when they are opened. 
-`:b#`, <Ctrl-I> and <Ctrl-O> works only assuming you didn't navigate one step 
-further in the documentation.
+very intuitive. Oftentimes I jump to definitions, a different file through
+netrw, an org file. `:bprev` would then end up in a completely different file,
+because buffers are ordered by when they are opened, not by history. `:b#`,
+<Ctrl-I>, <Ctrl-6> and <Ctrl-O> works only assuming you didn't navigate one step further
+in the documentation.
 
 I wanted to be able to browse buffers in a way that is similar to how you
 browse tabs in a browser. 
 
 ## Usage
 
-Install through any of your favorite plugin managers. For example, with
-[lazy](https://www.lazyvim.org).
-
 This plugin implements two functions: `require('buffer-browser').next()` and
 `require('buffer-browser').prev()`.
 
 You can easily map these to whatever you want. Here is an example `init.lua`:
 ```lua
-vim.api.nvim_set_keymap('n', '<leader>b[', require("buffer-browser").next(), {desc = "Next [B]uffer [[]"})
-vim.api.nvim_set_keymap('n', '<leader>b]', require("buffer-browser").prev(), {desc = "Previous [B]uffer []]"})
+vim.api.nvim_set_keymap('n', '<leader>b[', require("buffer_browser").next(), {desc = "Next [B]uffer [[]"})
+vim.api.nvim_set_keymap('n', '<leader>b]', require("buffer_browser").prev(), {desc = "Previous [B]uffer []]"})
 ```
 
-## Splits
+### Splits
+
+If a split has been performed, the new split will not preserve any of the previous history.
+
+## Insallation
+
+Install through any of your favorite plugin managers. 
+
+### [lazy](https://www.lazyvim.org). 
+
+Make sure to run the setup function. For example with lazy:
+
+```lua 
+{
+    'https://git.sr.ht/~marcc/BufferBrowser',
+}
+```
+
+Then run 
+
+```lua
+require('buffer_browser').setup()
+```
+
+
+### Configuration 
+
+You can configure the `filetype_filters` by passing a table to the `setup`
+function. This is the default config:
+
+```lua
+require('buffer-browser').setup({
+    -- '' + 'netrw' is used to filter out netrw.
+    filetype_filters = ['', 'netrw', 'gitcommit', 'TelescopePrompt']
+})
+```
+
+This can be used to filter out buffers you do not want in the history.
+
+#### Limitation
+
+To filter out netrw, we need to also filter out `''`, as the filetype
+occassionally gets set to that by netrw (not sure why...). This means files
+without filetype are filtered out.
 
-This plugin works with splits. If you have multiple splits open, the plugin
-will fork the split history and create a different "buffer history" for that 
-particular split.
+## Credits 
 
-## Credits
+The plugin is mostly a copy of
+[ton/vim-bufsurf](https://github.com/ton/vim-bufsurf), but rewritten in Lua and
+adds the ability to filter unwanted filetypes to get rid of netrw buffers. 
 
-The plugin is mostly based on [ton/vim-bufsurf](https://github.com/ton/vim-bufsurf), but rewritten in Lua. 
diff --git a/doc/BufferBrowser.txt b/doc/BufferBrowser.txt
new file mode 100644
index 0000000..d6bc2f3
--- /dev/null
+++ b/doc/BufferBrowser.txt
@@ -0,0 +1,45 @@
+*BufferBrowser.txt*  `:b#` on steroids. Browse your buffers like you browse history in a browser. *BufferBrowser*
+
+This plugin implements two functions: 
+  require('buffer-browser').next()
+  require('buffer-browser').prev()
+
+You can easily map these to whatever you want. Here is an example `init.lua`:
+  vim.api.nvim_set_keymap('n', '<leader>b[', require("buffer_browser").next(), {desc = "Next [B]uffer [[]"})
+  vim.api.nvim_set_keymap('n', '<leader>b]', require("buffer_browser").prev(), {desc = "Previous [B]uffer []]"})
+
+INSTALLATION
+
+Install through any of your favorite plugin managers. 
+
+### [lazy](https://www.lazyvim.org). 
+Make sure to run the setup function. For example with lazy:
+
+  {
+    'https://git.sr.ht/~marcc/BufferBrowser',
+    setup = function()
+        require('buffer_browser').setup()
+    end
+  }
+  
+  
+CONFIGURATION 
+
+You can configure the filetype_filters by passing a table to the setup function. For example with default config:
+
+  require('buffer-browser').setup({
+      -- '' + 'netrw' is used to filter out netrw.
+      filetype_filters = ['', 'netrw', 'gitcommit', 'TelescopePrompt']
+  })
+
+This can be used to filter out buffers you do not want in the history. If your
+current buffer ends with, for example netrw, it will be filtered out and not
+available in the history
+
+LIMITATIONS
+
+To filter out netrw, we need to also filter out '', as the filetype
+occassionally gets set to that by netrw (not sure why...). This means files
+without filetype are filtered out.
+
+
diff --git a/lua/buffer-browser.lua b/lua/buffer-browser.lua
deleted file mode 100644
index c6a41a8..0000000
--- a/lua/buffer-browser.lua
+++ /dev/null
@@ -1,94 +0,0 @@
--- BUFFER BROWSER
--- Author: Marc Coquand
--- See readme for explanation on what it does.
--- This code contains examples that can be used to test the code.
--- Run them in `lua %`
--- or with a code runner, like sniprun.
-local api = vim.api
-
-local function StateAppend(bufName, state, filters)
-	-- State has three fields, current = current buffer, previous = previous buffer, and future = future buffers
-	-- This function clears the future, and appends the current to the previous, and sets the current to the next
-
-	-- If filters matches the bufName, skip the buffer
-	if filters ~= nil then
-		for _, filter in ipairs(filters) do
-			if string.match(bufName, filter) then
-				return state
-			end
-		end
-	end
-
-	-- Clear the future
-	state.future = {}
-	-- Append the current to the previous
-	table.insert(state.previous, state.current)
-	-- Set the current to the next
-	state.current = bufName
-
-	return state
-end
--- Test StateAppend
--- local state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
--- print(StateAppend(6, state, {})['current'])
--- -- > 6
--- state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
--- print(StateAppend(6, state, {})['previous'][1])
--- -- > 2
--- state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
--- print(StateAppend(6, state, { 6 })['current'])
--- -- > 1
-
-local function StateGoBack(state)
-	-- Go back in the state by setting current to the first element of previous, and appending the current to the future
-	-- Check if past is empty, if so return state as is
-	if #state.previous == 0 then
-		return state
-	end
-
-	table.insert(state.future, state.current)
-	state.current = table.remove(state.previous, 1)
-	return state
-end
--- Test StateGoBack
--- local state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
--- print(StateGoBack(StateGoBack(StateGoBack(state)))['current'])
--- > 3
-
-local function StateGoForward(state)
-	-- Go forward in the state by setting current to the first element of future, and appending the current to the previous
-
-	-- Check if future is empty, if so return state as is
-	if #state.future == 0 then
-		return state
-	end
-
-	table.insert(state.previous, state.current)
-	state.current = table.remove(state.future, 1)
-
-	return state
-end
--- Test StateGoForward
--- local state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
--- print(StateGoForward(StateGoForward(StateGoForward(state)))['current'])
--- > 5
-
-function BufferEnter()
-	local bufName = api.nvim_buf_get_name(0)
-	local state = vim.g.buffer_browser_state
-	local filters = vim.g.buffer_browser_filters
-	vim.g.buffer_browser_state = StateAppend(bufName, state, filters)
-end
-
-local BufferBrowserGroup = api.nvim_create_augroup('BufferBrowser')
-
-api.nvim_create_autocmd('WinEnter', {
-	'*',
-	'lua BufferEnter()',
-	{ group = BufferBrowserGroup }
-})
-api.nvim_create_autocmd('BufEnter', {
-	'*',
-	'lua BufferEnter()',
-	{ group = BufferBrowserGroup }
-})
diff --git a/lua/buffer_browser.lua b/lua/buffer_browser.lua
new file mode 100644
index 0000000..0683f4b
--- /dev/null
+++ b/lua/buffer_browser.lua
@@ -0,0 +1,259 @@
+--[[
+BUFFER BROWSER
+Author: Marc Coquand
+
+The comments below the code can be used to test the functions. Run them in `lua %` or with a code runner, like sniprun.
+]]
+local api = vim.api
+
+--[[ STATE MANAGEMENT
+We make use of a Zipper to keep track of the state of the buffers
+(https://stackoverflow.com/questions/380438/what-is-the-zipper-data-structure-and-should-i-be-using-it)
+]]
+local function matchesFilter(filters, name)
+	if filters == nil then
+		return false
+	end
+
+	for _, filter in ipairs(filters) do
+		if name == filter then
+			return true
+		end
+	end
+	return false
+end
+
+
+local function StateAppend(bufNr, stateFiletype, state, filters)
+	if (state.current == bufNr) then
+		return state
+	end
+
+	-- if filters matches the filetype of the buffer we change from, don't add it to history
+	if (stateFiletype ~= nil and matchesFilter(filters, stateFiletype)) then
+		state.current = bufNr
+		return state
+	else
+		state.future = {}
+		table.insert(state.previous, 1, state.current)
+		state.current = bufNr
+
+		return state
+	end
+end
+
+local function StateGoBack(state)
+	-- Go back in the state by setting current to the first element of previous, and appending the current to the future
+	-- Check if past is empty, if so return state as is
+	if #state.previous == 0 then
+		return state
+	end
+
+	table.insert(state.future, 1, state.current)
+	state.current = table.remove(state.previous, 1)
+	return state
+end
+-- local state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
+-- print(StateGoBack(StateGoBack(StateGoBack(state)))['current'])
+-- > 3
+
+local function StateGoForward(state)
+	-- Go forward in the state by setting current to the first element of future, and appending the current to the previous
+
+	-- Check if future is empty, if so return state as is
+	if #state.future == 0 then
+		return state
+	end
+
+	table.insert(state.previous, 1, state.current)
+	state.current = table.remove(state.future, 1)
+
+	return state
+end
+-- local state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
+-- print(StateGoForward(StateGoForward(StateGoForward(state)))['current'])
+
+local function StateDelete(state, bufNr)
+	-- Delete bufNr from state.previous
+	for i, v in ipairs(state.previous) do
+		if v == bufNr then
+			table.remove(state.previous, i)
+		end
+	end
+
+	-- Delete bufNr from state.future
+	for i, v in ipairs(state.future) do
+		if v == bufNr then
+			table.remove(state.future, i)
+		end
+	end
+
+	-- If bufNr is current, set current to the first element of previous
+	if state.current == bufNr and #state.previous > 0 then
+		state.current = table.remove(state.previous, 1)
+		return state
+	end
+
+	-- If bufNr is current and we have a future
+	if state.current == bufNr and #state.future > 0 then
+		state.current = table.remove(state.future, 1)
+		return state
+	end
+
+	-- If bufNr is current, set current to the first element of future
+	if state.current == bufNr then
+		state.current = nil
+		return state
+	end
+	return state
+end
+-- local state = { current = 1, previous = { 2, 3 }, future = { 4, 5 } }
+-- print(StateDelete(state, 1)['current'])
+-- -- > 2
+
+local function stateIsEmpty(state)
+	return (state.current == nil and state.previous == nil and state.future == nil)
+end
+
+
+-- [[ EFFECTS ]]
+local function setState(state)
+	vim.w.buffer_browser_previous = state.previous
+	vim.w.buffer_browser_current = state.current
+	vim.w.buffer_browser_future = state.future
+end
+
+local function getState()
+	local current = vim.w.buffer_browser_current
+	local previous = vim.w.buffer_browser_previous
+	local future = vim.w.buffer_browser_future
+	return {
+		current = current,
+		previous = previous,
+		future = future,
+	}
+end
+
+local function initState(bufNr)
+	vim.w.buffer_browser_current = bufNr
+	vim.w.buffer_browser_previous = {}
+	vim.w.buffer_browser_future = {}
+end
+
+local function getBufNr()
+	local winnr = api.nvim_tabpage_get_win(0)
+	return api.nvim_win_get_buf(winnr)
+end
+
+local function getFiletype(bufnr)
+	if (bufnr == nil) then
+		return ''
+	end
+	return vim.bo[bufnr].filetype
+end
+
+--[[ AUTO COMMANDS ]]
+function BufferBrowserBufferEnter(args)
+	local bufNr = args.buf
+	local filters = vim.g.buffer_browser_filters
+
+	local state = getState()
+	if stateIsEmpty(state) then
+		initState(bufNr)
+	else
+		if (state.current ~= bufNr) then
+			local stateFiletype = getFiletype(state.current)
+			StateAppend(bufNr, stateFiletype, state, filters)
+			setState(state)
+		end
+	end
+end
+
+function BufferBrowserBufferWipeOut(args)
+	local buf = args.buf
+	local state = getState()
+	if not stateIsEmpty(state) then
+		StateDelete(state, buf)
+		setState(state)
+	end
+end
+
+local BufferBrowserGroup = api.nvim_create_augroup('BufferBrowser', { clear = true })
+
+api.nvim_create_autocmd({ 'WinEnter', 'BufEnter' },
+	{
+		group = BufferBrowserGroup,
+		pattern = '*',
+		callback = function(args)
+			BufferBrowserBufferEnter(args)
+		end
+	}
+)
+
+-- BufWipeout is called before deletion
+api.nvim_create_autocmd('BufWipeout',
+	{
+		group = BufferBrowserGroup,
+		pattern = '*',
+		callback = function(args)
+			BufferBrowserBufferWipeOut(args)
+		end
+	}
+)
+
+
+--[[ COMMANDS ]]
+local function next()
+	local bufnr = getBufNr()
+	local state = getState()
+
+	if stateIsEmpty(state) then
+		initState(bufnr)
+	else
+		StateGoForward(state)
+		setState(state)
+	end
+	api.nvim_command('buffer ' .. state.current)
+end
+
+local function prev()
+	local bufnr = getBufNr()
+	local state = getState()
+
+	if stateIsEmpty(state) then
+		initState(bufnr)
+	else
+		StateGoBack(state)
+		setState(state)
+	end
+	api.nvim_command('buffer ' .. state.current)
+end
+
+--[[ DEBUG ]]
+local function printBrowserHistory()
+	local state = getState()
+	print('Browser State Previous: ' .. vim.inspect(state.previous))
+	print('Browser State Current: ' .. vim.inspect(state.current))
+	print('Browser State Future: ' .. vim.inspect(state.future))
+end
+
+
+--[[ SETUP ]]
+local function setup(opts)
+	if (opts == nil) then
+		local default = {
+			'', 'netrw', 'gitcommit', 'TelescopePrompt'
+		}
+		vim.g.buffer_browser_filters = default
+	else
+		-- Filter is based on filetype
+		vim.g.buffer_browser_filters = opts.filetype_filters
+	end
+end
+
+return {
+	next = next,
+	prev = prev,
+	printBrowserHistory = printBrowserHistory,
+	setup = setup
+}
diff --git a/plugin/buffer-browser.vim b/plugin/buffer_browser.vim
index dfdb366..a37f436 100644
--- a/plugin/buffer-browser.vim
+++ b/plugin/buffer_browser.vim
@@ -1,13 +1,8 @@
 if exists('g:loaded_buffer_browser') | finish | endif " prevent loading file twice
 
-let s:save_cpo = &cpo " save user coptions
-set cpo&vim " reset them to defaults
-
 " command to run our plugin
 command! BufferBrowserNext lua require'buffer_browser'.next()
 command! BufferBrowserPrevious lua require'buffer_browser'.prev()
+command! BufferBrowserEcho lua require'buffer_browser'.printBrowserHistory()
 
-let &cpo = s:save_cpo " and restore after
-unlet s:save_cpo
-
-let g:loaded_whid = 1
+let g:loaded_buffer_browser = 1