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|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
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<h1>Lua-System</h1>
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<li><a href="../index.html">Index</a></li>
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<li><a href="../examples/read.lua.html">read.lua</a></li>
<li><strong>readline.lua</strong></li>
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<h2>readline.lua</h2>
<pre>
<span class="comment">--- An example class for reading a line of input from the user in a non-blocking way.
</span><span class="comment">-- It uses ANSI escape sequences to move the cursor and handle input.
</span><span class="comment">-- It can be used to read a line of input from the user, with a prompt.
</span><span class="comment">-- It can handle double-width UTF-8 characters.
</span><span class="comment">-- It can be used asynchroneously if <a href="../modules/system.html#sleep">system.sleep</a> is patched to yield to a coroutine scheduler.
</span>
<span class="keyword">local</span> sys = <span class="global">require</span>(<span class="string">"system"</span>)
<span class="comment">-- Mapping of key-sequences to key-names
</span><span class="keyword">local</span> key_names = {
[<span class="string">"\27[C"</span>] = <span class="string">"right"</span>,
[<span class="string">"\27[D"</span>] = <span class="string">"left"</span>,
[<span class="string">"\127"</span>] = <span class="string">"backspace"</span>,
[<span class="string">"\27[3~"</span>] = <span class="string">"delete"</span>,
[<span class="string">"\27[H"</span>] = <span class="string">"home"</span>,
[<span class="string">"\27[F"</span>] = <span class="string">"end"</span>,
[<span class="string">"\27"</span>] = <span class="string">"escape"</span>,
[<span class="string">"\9"</span>] = <span class="string">"tab"</span>,
[<span class="string">"\27[Z"</span>] = <span class="string">"shift-tab"</span>,
}
<span class="keyword">if</span> sys.windows <span class="keyword">then</span>
key_names[<span class="string">"\13"</span>] = <span class="string">"enter"</span>
<span class="keyword">else</span>
key_names[<span class="string">"\10"</span>] = <span class="string">"enter"</span>
<span class="keyword">end</span>
<span class="comment">-- Mapping of key-names to key-sequences
</span><span class="keyword">local</span> key_sequences = {}
<span class="keyword">for</span> k, v <span class="keyword">in</span> <span class="global">pairs</span>(key_names) <span class="keyword">do</span>
key_sequences[v] = k
<span class="keyword">end</span>
<span class="comment">-- bell character
</span><span class="keyword">local</span> <span class="keyword">function</span> <span class="function-name">bell</span>()
<span class="global">io</span>.<span class="function-name">write</span>(<span class="string">"\7"</span>)
<span class="global">io</span>.<span class="function-name">flush</span>()
<span class="keyword">end</span>
<span class="comment">-- generate string to move cursor horizontally
</span><span class="comment">-- positive goes right, negative goes left
</span><span class="keyword">local</span> <span class="keyword">function</span> <span class="function-name">cursor_move_horiz</span>(n)
<span class="keyword">if</span> n == <span class="number">0</span> <span class="keyword">then</span>
<span class="keyword">return</span> <span class="string">""</span>
<span class="keyword">end</span>
<span class="keyword">return</span> <span class="string">"\27["</span> .. (n > <span class="number">0</span> <span class="keyword">and</span> n <span class="keyword">or</span> -n) .. (n > <span class="number">0</span> <span class="keyword">and</span> <span class="string">"C"</span> <span class="keyword">or</span> <span class="string">"D"</span>)
<span class="keyword">end</span>
<span class="comment">-- -- generate string to move cursor vertically
</span><span class="comment">-- -- positive goes down, negative goes up
</span><span class="comment">-- local function cursor_move_vert(n)
</span><span class="comment">-- if n == 0 then
</span><span class="comment">-- return ""
</span><span class="comment">-- end
</span><span class="comment">-- return "\27[" .. (n > 0 and n or -n) .. (n > 0 and "B" or "A")
</span><span class="comment">-- end
</span>
<span class="comment">-- -- log to the line above the current line
</span><span class="comment">-- local function log(...)
</span><span class="comment">-- local arg = { n = select("#", ...), ...}
</span><span class="comment">-- for i = 1, arg.n do
</span><span class="comment">-- arg[i] = tostring(arg[i])
</span><span class="comment">-- end
</span><span class="comment">-- arg = " " .. table.concat(arg, " ") .. " "
</span>
<span class="comment">-- io.write(cursor_move_vert(-1), arg, cursor_move_vert(1), cursor_move_horiz(-#arg))
</span><span class="comment">-- end
</span>
<span class="comment">-- UTF8 character size in bytes
</span><span class="comment">-- @tparam number b the byte value of the first byte of a UTF8 character
</span><span class="keyword">local</span> <span class="keyword">function</span> <span class="function-name">utf8size</span>(b)
<span class="keyword">return</span> b < <span class="number">128</span> <span class="keyword">and</span> <span class="number">1</span> <span class="keyword">or</span> b < <span class="number">224</span> <span class="keyword">and</span> <span class="number">2</span> <span class="keyword">or</span> b < <span class="number">240</span> <span class="keyword">and</span> <span class="number">3</span> <span class="keyword">or</span> b < <span class="number">248</span> <span class="keyword">and</span> <span class="number">4</span>
<span class="keyword">end</span>
<span class="keyword">local</span> utf8parse <span class="keyword">do</span>
<span class="keyword">local</span> utf8_value_mt = {
__tostring = <span class="keyword">function</span>(self)
<span class="keyword">return</span> <span class="global">table</span>.<span class="function-name">concat</span>(self, <span class="string">""</span>)
<span class="keyword">end</span>,
}
<span class="comment">-- Parses a UTF8 string into list of individual characters.
</span> <span class="comment">-- key 'chars' gets the length in UTF8 characters, whilst # returns the length
</span> <span class="comment">-- for display (to handle double-width UTF8 chars).
</span> <span class="comment">-- in the list the double-width characters are followed by an empty string.
</span> <span class="comment">-- @tparam string s the UTF8 string to parse
</span> <span class="comment">-- @treturn table the list of characters
</span> <span class="keyword">function</span> <span class="function-name">utf8parse</span>(s)
<span class="keyword">local</span> t = <span class="global">setmetatable</span>({ chars = <span class="number">0</span> }, utf8_value_mt)
<span class="keyword">local</span> i = <span class="number">1</span>
<span class="keyword">while</span> i <= #s <span class="keyword">do</span>
<span class="keyword">local</span> b = s:<span class="function-name">byte</span>(i)
<span class="keyword">local</span> w = <span class="function-name">utf8size</span>(b)
<span class="keyword">local</span> char = s:<span class="function-name">sub</span>(i, i + w - <span class="number">1</span>)
t[#t + <span class="number">1</span>] = char
t.chars = t.chars + <span class="number">1</span>
<span class="keyword">if</span> sys.<span class="function-name">utf8cwidth</span>(char) == <span class="number">2</span> <span class="keyword">then</span>
<span class="comment">-- double width character, add empty string to keep the length of the
</span> <span class="comment">-- list the same as the character width on screen
</span> t[#t + <span class="number">1</span>] = <span class="string">""</span>
<span class="keyword">end</span>
i = i + w
<span class="keyword">end</span>
<span class="keyword">return</span> t
<span class="keyword">end</span>
<span class="keyword">end</span>
<span class="comment">-- inline tests for utf8parse
</span><span class="comment">-- do
</span><span class="comment">-- local t = utf8parse("a你b好c")
</span><span class="comment">-- assert(t[1] == "a")
</span><span class="comment">-- assert(t[2] == "你") -- double width
</span><span class="comment">-- assert(t[3] == "")
</span><span class="comment">-- assert(t[4] == "b")
</span><span class="comment">-- assert(t[5] == "好") -- double width
</span><span class="comment">-- assert(t[6] == "")
</span><span class="comment">-- assert(t[7] == "c")
</span><span class="comment">-- assert(#t == 7) -- size as displayed
</span><span class="comment">-- end
</span>
<span class="comment">-- readline class
</span>
<span class="keyword">local</span> readline = {}
readline.__index = readline
<span class="comment">--- Create a new readline object.
</span><span class="comment">-- @tparam table opts the options for the readline object
</span><span class="comment">-- @tparam[opt=""] string opts.prompt the prompt to display
</span><span class="comment">-- @tparam[opt=80] number opts.max_length the maximum length of the input (in characters, not bytes)
</span><span class="comment">-- @tparam[opt=""] string opts.value the default value
</span><span class="comment">-- @tparam[opt=<code>#value</code>] number opts.position of the cursor in the input
</span><span class="comment">-- @tparam[opt={"\10"/"\13"}] table opts.exit_keys an array of keys that will cause the readline to exit
</span><span class="comment">-- @tparam[opt=system.sleep] function opts.fsleep the sleep function to use (see <a href="../modules/system.html#readansi">system.readansi</a>)
</span><span class="comment">-- @treturn readline the new readline object
</span><span class="keyword">function</span> readline.<span class="function-name">new</span>(opts)
<span class="keyword">local</span> value = <span class="function-name">utf8parse</span>(opts.value <span class="keyword">or</span> <span class="string">""</span>)
<span class="keyword">local</span> prompt = <span class="function-name">utf8parse</span>(opts.prompt <span class="keyword">or</span> <span class="string">""</span>)
<span class="keyword">local</span> fsleep = opts.fsleep <span class="keyword">or</span> sys.sleep
<span class="keyword">local</span> pos = <span class="global">math</span>.<span class="function-name">floor</span>(opts.position <span class="keyword">or</span> (#value + <span class="number">1</span>))
pos = <span class="global">math</span>.<span class="function-name">max</span>(<span class="global">math</span>.<span class="function-name">min</span>(pos, (#value + <span class="number">1</span>)), <span class="number">1</span>)
<span class="keyword">local</span> len = <span class="global">math</span>.<span class="function-name">floor</span>(opts.max_length <span class="keyword">or</span> <span class="number">80</span>)
<span class="keyword">if</span> len < <span class="number">1</span> <span class="keyword">then</span>
<span class="global">error</span>(<span class="string">"max_length must be at least 1"</span>, <span class="number">2</span>)
<span class="keyword">end</span>
<span class="keyword">if</span> value.chars > len <span class="keyword">then</span>
<span class="global">error</span>(<span class="string">"value is longer than max_length"</span>, <span class="number">2</span>)
<span class="keyword">end</span>
<span class="keyword">local</span> exit_keys = {}
<span class="keyword">for</span> _, key <span class="keyword">in</span> <span class="global">ipairs</span>(opts.exit_keys <span class="keyword">or</span> {}) <span class="keyword">do</span>
exit_keys[key] = <span class="keyword">true</span>
<span class="keyword">end</span>
<span class="keyword">if</span> exit_keys[<span class="number">1</span>] == <span class="keyword">nil</span> <span class="keyword">then</span>
<span class="comment">-- nothing provided, default to Enter-key
</span> exit_keys[<span class="number">1</span>] = key_sequences.enter
<span class="keyword">end</span>
<span class="keyword">local</span> self = {
value = value, <span class="comment">-- the default value
</span> max_length = len, <span class="comment">-- the maximum length of the input
</span> prompt = prompt, <span class="comment">-- the prompt to display
</span> position = pos, <span class="comment">-- the current position in the input
</span> drawn_before = <span class="keyword">false</span>, <span class="comment">-- if the prompt has been drawn
</span> exit_keys = exit_keys, <span class="comment">-- the keys that will cause the readline to exit
</span> fsleep = fsleep, <span class="comment">-- the sleep function to use
</span> }
<span class="global">setmetatable</span>(self, readline)
<span class="keyword">return</span> self
<span class="keyword">end</span>
<span class="comment">-- draw the prompt and the input value, and position the cursor.
</span><span class="keyword">local</span> <span class="keyword">function</span> <span class="function-name">draw</span>(self, redraw)
<span class="keyword">if</span> redraw <span class="keyword">or</span> <span class="keyword">not</span> self.drawn_before <span class="keyword">then</span>
<span class="comment">-- we are at start of prompt
</span> self.drawn_before = <span class="keyword">true</span>
<span class="keyword">else</span>
<span class="comment">-- we are at current cursor position, move to start of prompt
</span> <span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(-(#self.prompt + self.position)))
<span class="keyword">end</span>
<span class="comment">-- write prompt & value
</span> <span class="global">io</span>.<span class="function-name">write</span>(<span class="global">tostring</span>(self.prompt) .. <span class="global">tostring</span>(self.value))
<span class="comment">-- clear remainder of input size
</span> <span class="global">io</span>.<span class="function-name">write</span>(<span class="global">string</span>.<span class="function-name">rep</span>(<span class="string">" "</span>, self.max_length - self.value.chars))
<span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(-(self.max_length - self.value.chars)))
<span class="comment">-- move to cursor position
</span> <span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(-(#self.value + <span class="number">1</span> - self.position)))
<span class="global">io</span>.<span class="function-name">flush</span>()
<span class="keyword">end</span>
<span class="keyword">local</span> handle_key <span class="keyword">do</span> <span class="comment">-- keyboard input handler
</span>
<span class="keyword">local</span> key_handlers
key_handlers = {
left = <span class="keyword">function</span>(self)
<span class="keyword">if</span> self.position == <span class="number">1</span> <span class="keyword">then</span>
<span class="function-name">bell</span>()
<span class="keyword">return</span>
<span class="keyword">end</span>
<span class="keyword">local</span> new_pos = self.position - <span class="number">1</span>
<span class="keyword">while</span> self.value[new_pos] == <span class="string">""</span> <span class="keyword">do</span> <span class="comment">-- skip empty strings; double width chars
</span> new_pos = new_pos - <span class="number">1</span>
<span class="keyword">end</span>
<span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(-(self.position - new_pos)))
<span class="global">io</span>.<span class="function-name">flush</span>()
self.position = new_pos
<span class="keyword">end</span>,
right = <span class="keyword">function</span>(self)
<span class="keyword">if</span> self.position == #self.value + <span class="number">1</span> <span class="keyword">then</span>
<span class="function-name">bell</span>()
<span class="keyword">return</span>
<span class="keyword">end</span>
<span class="keyword">local</span> new_pos = self.position + <span class="number">1</span>
<span class="keyword">while</span> self.value[new_pos] == <span class="string">""</span> <span class="keyword">do</span> <span class="comment">-- skip empty strings; double width chars
</span> new_pos = new_pos + <span class="number">1</span>
<span class="keyword">end</span>
<span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(new_pos - self.position))
<span class="global">io</span>.<span class="function-name">flush</span>()
self.position = new_pos
<span class="keyword">end</span>,
backspace = <span class="keyword">function</span>(self)
<span class="keyword">if</span> self.position == <span class="number">1</span> <span class="keyword">then</span>
<span class="function-name">bell</span>()
<span class="keyword">return</span>
<span class="keyword">end</span>
<span class="keyword">while</span> self.value[self.position - <span class="number">1</span>] == <span class="string">""</span> <span class="keyword">do</span> <span class="comment">-- remove empty strings; double width chars
</span> <span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(-<span class="number">1</span>))
self.position = self.position - <span class="number">1</span>
<span class="global">table</span>.<span class="function-name">remove</span>(self.value, self.position)
<span class="keyword">end</span>
<span class="comment">-- remove char itself
</span> <span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(-<span class="number">1</span>))
self.position = self.position - <span class="number">1</span>
<span class="global">table</span>.<span class="function-name">remove</span>(self.value, self.position)
self.value.chars = self.value.chars - <span class="number">1</span>
<span class="function-name">draw</span>(self)
<span class="keyword">end</span>,
home = <span class="keyword">function</span>(self)
<span class="keyword">local</span> new_pos = <span class="number">1</span>
<span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(new_pos - self.position))
self.position = new_pos
<span class="keyword">end</span>,
[<span class="string">"end"</span>] = <span class="keyword">function</span>(self)
<span class="keyword">local</span> new_pos = #self.value + <span class="number">1</span>
<span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(new_pos - self.position))
self.position = new_pos
<span class="keyword">end</span>,
delete = <span class="keyword">function</span>(self)
<span class="keyword">if</span> self.position > #self.value <span class="keyword">then</span>
<span class="function-name">bell</span>()
<span class="keyword">return</span>
<span class="keyword">end</span>
key_handlers.<span class="function-name">right</span>(self)
key_handlers.<span class="function-name">backspace</span>(self)
<span class="keyword">end</span>,
}
<span class="comment">-- handles a single input key/ansi-sequence.
</span> <span class="comment">-- @tparam string key the key or ansi-sequence (from <a href="../modules/system.html#readansi">system.readansi</a>)
</span> <span class="comment">-- @tparam string keytype the type of the key, either "char" or "ansi" (from <a href="../modules/system.html#readansi">system.readansi</a>)
</span> <span class="comment">-- @treturn string status the status of the key handling, either "ok", "exit_key" or an error message
</span> <span class="keyword">function</span> <span class="function-name">handle_key</span>(self, key, keytype)
<span class="keyword">if</span> self.exit_keys[key] <span class="keyword">then</span>
<span class="comment">-- registered exit key
</span> <span class="keyword">return</span> <span class="string">"exit_key"</span>
<span class="keyword">end</span>
<span class="keyword">local</span> handler = key_handlers[key_names[key] <span class="keyword">or</span> <span class="keyword">true</span> ]
<span class="keyword">if</span> handler <span class="keyword">then</span>
<span class="function-name">handler</span>(self)
<span class="keyword">return</span> <span class="string">"ok"</span>
<span class="keyword">end</span>
<span class="keyword">if</span> keytype == <span class="string">"ansi"</span> <span class="keyword">then</span>
<span class="comment">-- we got an ansi sequence, but dunno how to handle it, ignore
</span> <span class="comment">-- print("unhandled ansi: ", key:sub(2,-1), string.byte(key, 1, -1))
</span> <span class="function-name">bell</span>()
<span class="keyword">return</span> <span class="string">"ok"</span>
<span class="keyword">end</span>
<span class="comment">-- just a single key
</span> <span class="keyword">if</span> key < <span class="string">" "</span> <span class="keyword">then</span>
<span class="comment">-- control character
</span> <span class="function-name">bell</span>()
<span class="keyword">return</span> <span class="string">"ok"</span>
<span class="keyword">end</span>
<span class="keyword">if</span> self.value.chars >= self.max_length <span class="keyword">then</span>
<span class="function-name">bell</span>()
<span class="keyword">return</span> <span class="string">"ok"</span>
<span class="keyword">end</span>
<span class="comment">-- insert the key into the value
</span> <span class="keyword">if</span> sys.<span class="function-name">utf8cwidth</span>(key) == <span class="number">2</span> <span class="keyword">then</span>
<span class="comment">-- double width character, insert empty string after it
</span> <span class="global">table</span>.<span class="function-name">insert</span>(self.value, self.position, <span class="string">""</span>)
<span class="global">table</span>.<span class="function-name">insert</span>(self.value, self.position, key)
self.position = self.position + <span class="number">2</span>
<span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(<span class="number">2</span>))
<span class="keyword">else</span>
<span class="global">table</span>.<span class="function-name">insert</span>(self.value, self.position, key)
self.position = self.position + <span class="number">1</span>
<span class="global">io</span>.<span class="function-name">write</span>(<span class="function-name">cursor_move_horiz</span>(<span class="number">1</span>))
<span class="keyword">end</span>
self.value.chars = self.value.chars + <span class="number">1</span>
<span class="function-name">draw</span>(self)
<span class="keyword">return</span> <span class="string">"ok"</span>
<span class="keyword">end</span>
<span class="keyword">end</span>
<span class="comment">--- Get_size returns the maximum size of the input box (prompt + input).
</span><span class="comment">-- The size is in rows and columns. Columns is determined by
</span><span class="comment">-- the prompt and the <code>max_length * 2</code> (characters can be double-width).
</span><span class="comment">-- @treturn number the number of rows (always 1)
</span><span class="comment">-- @treturn number the number of columns
</span><span class="keyword">function</span> readline:<span class="function-name">get_size</span>()
<span class="keyword">return</span> <span class="number">1</span>, #self.prompt + self.max_length * <span class="number">2</span>
<span class="keyword">end</span>
<span class="comment">--- Get coordinates of the cursor in the input box (prompt + input).
</span><span class="comment">-- The coordinates are 1-based. They are returned as row and column, within the
</span><span class="comment">-- size as reported by <code>get_size</code>.
</span><span class="comment">-- @treturn number the row of the cursor (always 1)
</span><span class="comment">-- @treturn number the column of the cursor
</span><span class="keyword">function</span> readline:<span class="function-name">get_cursor</span>()
<span class="keyword">return</span> <span class="number">1</span>, #self.prompt + self.position
<span class="keyword">end</span>
<span class="comment">--- Set the coordinates of the cursor in the input box (prompt + input).
</span><span class="comment">-- The coordinates are 1-based. They are expected to be within the
</span><span class="comment">-- size as reported by <code>get_size</code>, and beyond the prompt.
</span><span class="comment">-- If the position is invalid, it will be corrected.
</span><span class="comment">-- Use the results to check if the position was adjusted.
</span><span class="comment">-- @tparam number row the row of the cursor (always 1)
</span><span class="comment">-- @tparam number col the column of the cursor
</span><span class="comment">-- @return results of get_cursor
</span><span class="keyword">function</span> readline:<span class="function-name">set_cursor</span>(row, col)
<span class="keyword">local</span> l_prompt = #self.prompt
<span class="keyword">local</span> l_value = #self.value
<span class="keyword">if</span> col < l_prompt + <span class="number">1</span> <span class="keyword">then</span>
col = l_prompt + <span class="number">1</span>
<span class="keyword">elseif</span> col > l_prompt + l_value + <span class="number">1</span> <span class="keyword">then</span>
col = l_prompt + l_value + <span class="number">1</span>
<span class="keyword">end</span>
<span class="keyword">while</span> self.value[col - l_prompt] == <span class="string">""</span> <span class="keyword">do</span>
col = col - <span class="number">1</span> <span class="comment">-- on an empty string, so move back to start of double-width char
</span> <span class="keyword">end</span>
<span class="keyword">local</span> new_pos = col - l_prompt
<span class="function-name">cursor_move_horiz</span>(self.position - new_pos)
<span class="global">io</span>.<span class="function-name">flush</span>()
self.position = new_pos
<span class="keyword">return</span> self:<span class="function-name">get_cursor</span>()
<span class="keyword">end</span>
<span class="comment">--- Read a line of input from the user.
</span><span class="comment">-- It will first print the <code>prompt</code> and then wait for input. Ensure the cursor
</span><span class="comment">-- is at the correct position before calling this function. This function will
</span><span class="comment">-- do all cursor movements in a relative way.
</span><span class="comment">-- Can be called again after an exit-key or timeout has occurred. Just make sure
</span><span class="comment">-- the cursor is at the same position where is was when it returned the last time.
</span><span class="comment">-- Alternatively the cursor can be set to the position of the prompt (the position
</span><span class="comment">-- the cursor was in before the first call), and the parameter <code>redraw</code> can be set
</span><span class="comment">-- to <code>true</code>.
</span><span class="comment">-- @tparam[opt=math.huge] number timeout the maximum time to wait for input in seconds
</span><span class="comment">-- @tparam[opt=false] boolean redraw if <code>true</code> the prompt will be redrawn (cursor must be at prompt position!)
</span><span class="comment">-- @treturn[1] string the input string as entered the user
</span><span class="comment">-- @treturn[1] string the exit-key used to exit the readline (see <code>new</code>)
</span><span class="comment">-- @treturn[2] nil when input is incomplete
</span><span class="comment">-- @treturn[2] string error message, the reason why the input is incomplete, <code>"timeout"</code>, or an error reading a key
</span><span class="keyword">function</span> readline:<span class="function-name">__call</span>(timeout, redraw)
<span class="function-name">draw</span>(self, redraw)
timeout = timeout <span class="keyword">or</span> <span class="global">math</span>.huge
<span class="keyword">local</span> timeout_end = sys.<span class="function-name">gettime</span>() + timeout
<span class="keyword">while</span> <span class="keyword">true</span> <span class="keyword">do</span>
<span class="keyword">local</span> key, keytype = sys.<span class="function-name">readansi</span>(timeout_end - sys.<span class="function-name">gettime</span>(), self.fsleep)
<span class="keyword">if</span> <span class="keyword">not</span> key <span class="keyword">then</span>
<span class="comment">-- error or timeout
</span> <span class="keyword">return</span> <span class="keyword">nil</span>, keytype
<span class="keyword">end</span>
<span class="keyword">local</span> status = <span class="function-name">handle_key</span>(self, key, keytype)
<span class="keyword">if</span> status == <span class="string">"exit_key"</span> <span class="keyword">then</span>
<span class="keyword">return</span> <span class="global">tostring</span>(self.value), key
<span class="keyword">elseif</span> status ~= <span class="string">"ok"</span> <span class="keyword">then</span>
<span class="global">error</span>(<span class="string">"unknown status received: "</span> .. <span class="global">tostring</span>(status))
<span class="keyword">end</span>
<span class="keyword">end</span>
<span class="keyword">end</span>
<span class="comment">-- return readline -- normally we'd return here, but for the example we continue
</span>
<span class="keyword">local</span> backup = sys.<span class="function-name">termbackup</span>()
<span class="comment">-- setup Windows console to handle ANSI processing
</span>sys.<span class="function-name">setconsoleflags</span>(<span class="global">io</span>.stdout, sys.<span class="function-name">getconsoleflags</span>(<span class="global">io</span>.stdout) + sys.COF_VIRTUAL_TERMINAL_PROCESSING)
sys.<span class="function-name">setconsoleflags</span>(<span class="global">io</span>.stdin, sys.<span class="function-name">getconsoleflags</span>(<span class="global">io</span>.stdin) + sys.CIF_VIRTUAL_TERMINAL_INPUT)
<span class="comment">-- set output to UTF-8
</span>sys.<span class="function-name">setconsoleoutputcp</span>(sys.CODEPAGE_UTF8)
<span class="comment">-- setup Posix terminal to disable canonical mode and echo
</span>sys.<span class="function-name">tcsetattr</span>(<span class="global">io</span>.stdin, sys.TCSANOW, {
lflag = sys.<span class="function-name">tcgetattr</span>(<span class="global">io</span>.stdin).lflag - sys.L_ICANON - sys.L_ECHO,
})
<span class="comment">-- setup stdin to non-blocking mode
</span>sys.<span class="function-name">setnonblock</span>(<span class="global">io</span>.stdin, <span class="keyword">true</span>)
<span class="keyword">local</span> rl = readline.<span class="function-name">new</span>{
prompt = <span class="string">"Enter something: "</span>,
max_length = <span class="number">60</span>,
value = <span class="string">"Hello, 你-好 World 🚀!"</span>,
<span class="comment">-- position = 2,
</span> exit_keys = {key_sequences.enter, <span class="string">"\27"</span>, <span class="string">"\t"</span>, <span class="string">"\27[Z"</span>}, <span class="comment">-- enter, escape, tab, shift-tab
</span> fsleep = sys.sleep,
}
<span class="keyword">local</span> result, key = <span class="function-name">rl</span>()
<span class="global">print</span>(<span class="string">""</span>) <span class="comment">-- newline after input, to move cursor down from the input line
</span><span class="global">print</span>(<span class="string">"Result (string): '"</span> .. result .. <span class="string">"'"</span>)
<span class="global">print</span>(<span class="string">"Result (bytes):"</span>, result:<span class="function-name">byte</span>(<span class="number">1</span>,-<span class="number">1</span>))
<span class="global">print</span>(<span class="string">"Exit-Key (bytes):"</span>, key:<span class="function-name">byte</span>(<span class="number">1</span>,-<span class="number">1</span>))
<span class="comment">-- Clean up afterwards
</span>sys.<span class="function-name">termrestore</span>(backup)</pre>
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<i style="float:right;">Last updated 2025-03-12 15:17:50 </i>
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