From a0f45aece21a6280633023ec84f60eb0d5e0849a Mon Sep 17 00:00:00 2001
From: Raymaekers Luca <raymaekers.luca@gmail.com>
Date: Thu, 20 Jun 2024 23:46:00 +0200
Subject: checkpoint

---
 config/essentials/vis/complete-line.lua | 141 ++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 config/essentials/vis/complete-line.lua

(limited to 'config/essentials/vis/complete-line.lua')

diff --git a/config/essentials/vis/complete-line.lua b/config/essentials/vis/complete-line.lua
new file mode 100644
index 0000000..93728a3
--- /dev/null
+++ b/config/essentials/vis/complete-line.lua
@@ -0,0 +1,141 @@
+-- SPDX-License-Identifier: GPL-3.0-or-later
+-- © 2020 Georgi Kirilov
+local progname = ...
+
+local lpeg = require("lpeg")
+local R, C, Cmt = lpeg.R, lpeg.C, lpeg.Cmt
+
+-- copied from vis.h
+local VIS_MOVE_NOP = 64
+
+local cont = R("\128\191")
+
+local charpattern = R("\0\127") + R("\194\223") * cont + R("\224\239") * cont *
+                        cont + R("\240\244") * cont * cont * cont
+
+local function concat_keys(tbl)
+    local keys = {}
+    for k in pairs(tbl) do table.insert(keys, k) end
+    return table.concat(keys, "\n"), #keys
+end
+
+local function line_complete()
+    local file = vis.win.file
+    local sel = vis.win.selection
+    local cur_line = file.lines[sel.line]
+    local indent_patt = "^[ \t\v\f]+"
+    local prefix = cur_line:sub(1, sel.col - 1):gsub(indent_patt, "")
+    local candidates = {}
+    for l in file:lines_iterator() do
+        local unindented = l:gsub(indent_patt, "")
+        local start, finish = unindented:find(prefix, 1, true)
+        if start == 1 and finish < #unindented then
+            candidates[unindented] = true
+        end
+    end
+    local candidates_str, n = concat_keys(candidates)
+    if n < 2 then
+        if n == 1 then vis:insert(candidates_str:sub(#prefix + 1)) end
+        return
+    end
+    -- XXX: with too many candidates this command will become longer that the shell can handle:
+    local command = string.format("vis-menu -l %d <<'EOF'\n%s\nEOF\n",
+                                  math.min(n, math.ceil(vis.win.height / 2)),
+                                  candidates_str)
+    local status, output = vis:pipe(nil, nil, command)
+    if n > 0 and status == 0 then
+        vis:insert(output:sub(#prefix + 1):gsub("\n$", ""))
+    end
+end
+
+local function selection_by_pos(pos)
+    for s in vis.win:selections_iterator() do
+        if s.pos == pos then return s end
+    end
+end
+
+local function charwidth(cells_so_far, char)
+    if char == "\t" then
+        local tw = vis.tabwidth or 8
+        local trail = cells_so_far % tw
+        return tw - trail
+    else
+        return 1
+    end
+end
+
+local function virtcol(line, col)
+    local ncells = 0
+    local nchars = 0
+    local function upto(_, _, char)
+        if nchars < col - 1 then
+            ncells = ncells + charwidth(ncells, char)
+            nchars = nchars + 1
+            return true
+        end
+    end
+    (Cmt(C(charpattern), upto) ^ 0):match(line)
+    return ncells + 1
+end
+
+local function neighbor(lines, ln, col, direction)
+    local line = ln + direction > 0 and lines[ln + direction]
+    if not line then return end
+    local column = virtcol(lines[ln], col)
+    local ncells = 0
+    local function upto(_, _, char)
+        ncells = ncells + charwidth(ncells, char)
+        return ncells < column
+    end
+    return
+        (Cmt(C(charpattern), upto) ^ (-column + 1) / 0 * C(charpattern)):match(
+            line)
+end
+
+local function dup_neighbor(direction)
+    return function(file, _, pos)
+        local sel = selection_by_pos(pos)
+        local char = neighbor(file.lines, sel.line, sel.col, direction)
+        if not char then return pos end
+        file:insert(pos, char)
+        return pos + #char
+    end
+end
+
+local function dup_neighbor_feedkeys(direction)
+    local sel = vis.win.selection
+    local file = vis.win.file
+    local char = neighbor(file.lines, sel.line, sel.col, direction)
+    if not char then return end
+    vis:feedkeys(char)
+end
+
+local function operator(handler)
+    local id = vis:operator_register(handler)
+    return id >= 0 and function()
+        vis:operator(id)
+        vis:motion(VIS_MOVE_NOP)
+    end
+end
+
+vis.events.subscribe(vis.events.INIT, function()
+    local function h(msg) return string.format("|@%s| %s", progname, msg) end
+
+    local function column_complete(direction)
+        local binding = operator(dup_neighbor(direction))
+        return function()
+            if #vis.win.selections == 1 then
+                dup_neighbor_feedkeys(direction)
+            else
+                return binding()
+            end
+        end
+    end
+
+    vis:map(vis.modes.INSERT, "<C-y>", column_complete(-1),
+            h "Insert the character which is above the cursor")
+    vis:map(vis.modes.INSERT, "<C-e>", column_complete(1),
+            h "Insert the character which is below the cursor")
+    vis:map(vis.modes.INSERT, "<C-x><C-l>", line_complete,
+            h "Complete the current line")
+end)
-- 
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