import https://github.com/majek/lua-channels

Also a little test program to demo channels in action.

1 files changed, 409 insertions, 0 deletions

diff --git a/sieve.tlv b/sieve.tlv
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+++ b/sieve.tlv
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+# .tlv file generated by https://github.com/akkartik/teliva
+# You may edit it if you are careful; however, you may see cryptic errors if you
+# violate Teliva's assumptions.
+#
+# .tlv files are representations of Teliva programs. Teliva programs consist of
+# sequences of definitions. Each definition is a table of key/value pairs. Keys
+# and values are both strings.
+#
+# Lines in .tlv files always follow exactly one of the following forms:
+# - comment lines at the top of the file starting with '#' at column 0
+# - beginnings of definitions starting with '- ' at column 0, followed by a
+#   key/value pair
+# - key/value pairs consisting of '  ' at column 0, containing either a
+#   spaceless value on the same line, or a multi-line value
+# - multiline values indented by more than 2 spaces, starting with a '>'
+#
+# If these constraints are violated, Teliva may unceremoniously crash. Please
+# report bugs at http://akkartik.name/contact
+- __teliva_timestamp: original
+  str_helpers:
+    >-- some string helpers from http://lua-users.org/wiki/StringIndexing
+    >
+    >-- index characters using []
+    >getmetatable('').__index = function(str,i)
+    >  if type(i) == 'number' then
+    >    return string.sub(str,i,i)
+    >  else
+    >    return string[i]
+    >  end
+    >end
+    >
+    >-- ranges using (), selected bytes using {}
+    >getmetatable('').__call = function(str,i,j)
+    >  if type(i)~='table' then
+    >    return string.sub(str,i,j)
+    >  else
+    >    local t={}
+    >    for k,v in ipairs(i) do
+    >      t[k]=string.sub(str,v,v)
+    >    end
+    >    return table.concat(t)
+    >  end
+    >end
+    >
+    >-- iterate over an ordered sequence
+    >function q(x)
+    >  if type(x) == 'string' then
+    >    return x:gmatch('.')
+    >  else
+    >    return ipairs(x)
+    >  end
+    >end
+    >
+    >-- insert within string
+    >function string.insert(str1, str2, pos)
+    >  return str1:sub(1,pos)..str2..str1:sub(pos+1)
+    >end
+    >
+    >function string.remove(s, pos)
+    >  return s:sub(1,pos-1)..s:sub(pos+1)
+    >end
+    >
+    >-- TODO: backport utf-8 support from Lua 5.3
+- __teliva_timestamp: original
+  debugy:
+    >debugy = 5
+- __teliva_timestamp: original
+  dbg:
+    >-- helper for debug by print; overlay debug information towards the right
+    >-- reset debugy every time you refresh screen
+    >function dbg(window, s)
+    >  local oldy = 0
+    >  local oldx = 0
+    >  oldy, oldx = window:getyx()
+    >  window:mvaddstr(debugy, 60, s)
+    >  debugy = debugy+1
+    >  window:mvaddstr(oldy, oldx, '')
+    >end
+- __teliva_timestamp: original
+  check_eq:
+    >function check_eq(x, expected, msg)
+    >  if eq(x, expected) then
+    >    curses.addch('.')
+    >  else
+    >    print('F - '..msg)
+    >    print('  expected '..str(expected)..' but got '..str(x))
+    >    teliva_num_test_failures = teliva_num_test_failures + 1
+    >    -- overlay first test failure on editors
+    >    if teliva_first_failure == nil then
+    >      teliva_first_failure = msg
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  eq:
+    >function eq(a, b)
+    >  if type(a) ~= type(b) then return false end
+    >  if type(a) == 'table' then
+    >    if #a ~= #b then return false end
+    >    for k, v in pairs(a) do
+    >      if b[k] ~= v then
+    >        return false
+    >      end
+    >      return true
+    >    end
+    >  end
+    >  return a == b
+    >end
+- __teliva_timestamp: original
+  str:
+    >-- smarter tostring
+    >-- slow; used only for debugging
+    >function str(x)
+    >  if type(x) == 'table' then
+    >    local result = ''
+    >    result = result..#x..'{'
+    >    for k, v in pairs(x) do
+    >      result = result..str(k)..'='..str(v)..', '
+    >    end
+    >    result = result..'}'
+    >    return result
+    >  end
+    >  return tostring(x)
+    >end
+- __teliva_timestamp: original
+  map:
+    >-- only for arrays
+    >function map(l, f)
+    >  result = {}
+    >  for _, x in ipairs(l) do
+    >    table.insert(result, f(x))
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  reduce:
+    >-- only for arrays
+    >function reduce(l, f, init)
+    >  result = init
+    >  for _, x in ipairs(l) do
+    >    result = f(result, x)
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  filter:
+    >-- only for arrays
+    >function filter(l, f)
+    >  result = {}
+    >  for _, x in ipairs(l) do
+    >    if f(x) then
+    >      table.insert(result, x)
+    >    end
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp: original
+  find_index:
+    >function find_index(arr, x)
+    >  for n, y in ipairs(arr) do
+    >    if x == y then
+    >      return n
+    >    end
+    >  end
+    >end
+- __teliva_timestamp: original
+  trim:
+    >function trim(s)
+    >  return s:gsub('^%s*', ''):gsub('%s*$', '')
+    >end
+- __teliva_timestamp: original
+  split:
+    >function split(s, d)
+    >  result = {}
+    >  for match in (s..d):gmatch("(.-)"..d) do
+    >    table.insert(result, match);
+    >  end
+    >  return result
+    >end
+- __teliva_timestamp:
+    >Mon Feb 21 17:45:04 2022
+  sort_string:
+    >function sort_string(s)
+    >  tmp = {}
+    >  for i=1,#s do
+    >    table.insert(tmp, s[i])
+    >  end
+    >  table.sort(tmp)
+    >  local result = ''
+    >  for _, c in pairs(tmp) do
+    >    result = result..c
+    >  end
+    >  return result
+    >end
+    >
+    >function test_sort_string(s)
+    >  check_eq(sort_string(''), '', 'test_sort_string: empty')
+    >  check_eq(sort_string('ba'), 'ab', 'test_sort_string: non-empty')
+    >  check_eq(sort_string('abba'), 'aabb', 'test_sort_string: duplicates')
+    >end
+- __teliva_timestamp: original
+  append:
+    >-- concatenate list 'elems' into 'l', modifying 'l' in the process
+    >function append(l, elems)
+    >  for i=1,#elems do
+    >    l[#l+1] = elems[i]
+    >  end
+    >end
+- __teliva_timestamp: original
+  window:
+    >window = curses.stdscr()
+- __teliva_timestamp: original
+  render:
+    >function render(window)
+    >  window:clear()
+    >  -- draw stuff to screen here
+    >  window:attron(curses.A_BOLD)
+    >  window:mvaddstr(1, 5, "example app")
+    >  window:attrset(curses.A_NORMAL)
+    >  for i=0,15 do
+    >    window:attrset(curses.color_pair(i))
+    >    window:mvaddstr(3+i, 5, "========================")
+    >  end
+    >  curses.refresh()
+    >end
+- __teliva_timestamp: original
+  menu:
+    >-- To show app-specific hotkeys in the menu bar, add hotkey/command
+    >-- arrays of strings to the menu array.
+    >menu = {}
+- __teliva_timestamp: original
+  update:
+    >function update(window)
+    >  local key = curses.getch()
+    >  -- process key here
+    >end
+- __teliva_timestamp: original
+  init_colors:
+    >function init_colors()
+    >  for i=0,7 do
+    >    curses.init_pair(i, i, -1)
+    >  end
+    >  curses.init_pair(8, 7, 0)
+    >  curses.init_pair(9, 7, 1)
+    >  curses.init_pair(10, 7, 2)
+    >  curses.init_pair(11, 7, 3)
+    >  curses.init_pair(12, 7, 4)
+    >  curses.init_pair(13, 7, 5)
+    >  curses.init_pair(14, 7, 6)
+    >  curses.init_pair(15, -1, 15)
+    >end
+- __teliva_timestamp: original
+  main:
+    >function main()
+    >  init_colors()
+    >
+    >  while true do
+    >    render(window)
+    >    update(window)
+    >  end
+    >end
+- __teliva_timestamp: original
+  doc:blurb:
+    >To show a brief description of the app on the 'big picture' screen, put the text in a special buffer called 'doc:blurb'.
+    >
+    >You can also override the default big picture screen entirely by creating a buffer called 'doc:main'.
+- __teliva_timestamp:
+    >Sat Feb 26 21:49:00 2022
+  main:
+    >function main()
+    >  task.spawn(main_task)
+    >  task.scheduler()
+    >  print('out of scheduler')
+    >  curses.getch()
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 21:50:11 2022
+  main_task:
+    >function main_task()
+    >  local c = task.Channel:new()
+    >  task.spawn(counter, c)
+    >  for i=1,10 do
+    >    print(c:recv())
+    >  end
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 21:50:11 2022
+  __teliva_note:
+    >a simple counter
+  counter:
+    >function counter(c)
+    >  local i = 2
+    >  while true do
+    >    c:send(i)
+    >    i = i+1
+    >  end
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 21:54:53 2022
+  filter_task:
+    >function filter_task(p, cin, cout)
+    >  while true do
+    >    local i = cin:recv()
+    >    if i%p ~= 0 then
+    >      cout:send(i)
+    >    end
+    >  end
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 21:55:46 2022
+  main_task:
+    >function main_task()
+    >  local primes = task.Channel:new()
+    >  task.spawn(sieve, primes)
+    >  for i=1,10 do
+    >    print(primes:recv())
+    >  end
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 21:59:37 2022
+  __teliva_note:
+    >filter out multiples of a single number
+  sieve:
+    >function sieve(ch)
+    >  local iota = task.Channel:new()
+    >  task.spawn(counter, iota)
+    >  task.spawn(filter_task, 2, iota, ch)
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 22:08:07 2022
+  __teliva_note:
+    >implement the complete sieve algorithm
+  sieve:
+    >-- Set up a Sieve of Eratosthenes (https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes)
+    >-- for computing prime numbers by chaining tasks, one per prime.
+    >-- Each task is responsible for filtering out all multiples of its prime.
+    >function sieve(primes_ch)
+    >  local c = task.Channel:new()
+    >  task.spawn(counter, c)
+    >  while true do
+    >    local p, newc = c:recv(), task.Channel:new()
+    >    primes_ch:send(p)
+    >    task.spawn(filter_task, p, c, newc)
+    >    c = newc
+    >  end
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 22:09:47 2022
+  main_task:
+    >function main_task(window)
+    >  local primes = task.Channel:new()
+    >  task.spawn(sieve, primes)
+    >  while true do
+    >    window:addstr(primes:recv())
+    >    window:addstr(' ')
+    >    window:refresh()
+    >  end
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 22:08:52 2022
+  __teliva_note:
+    >infinite primes
+  main:
+    >function main()
+    >  window:nodelay(true)
+    >  window:clear()
+    >  task.spawn(main_task, window)
+    >  task.scheduler()
+    >  print('key pressed; done')
+    >  window:nodelay(false)
+    >  curses.getch()
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 22:09:47 2022
+  __teliva_note:
+    >clear screen when it fills up; pause on keypress
+    >
+    >In Teliva getch() implicitly refreshes the screen.
+  main_task:
+    >function main_task(window)
+    >  local primes = task.Channel:new()
+    >  task.spawn(sieve, primes)
+    >  local h, w = window:getmaxyx()
+    >  while true do
+    >    window:addstr(primes:recv())
+    >    window:addstr(' ')
+    >    local c = curses.getch()
+    >    if c then break end  -- key pressed
+    >    local y, x = window:getyx()
+    >    if y > h-1 then
+    >      window:clear()
+    >    end
+    >  end
+    >end
+- __teliva_timestamp:
+    >Sat Feb 26 22:27:25 2022
+  doc:blurb:
+    >Sieve of Eratosthenes
+    >https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
+    >
+    >A demonstration of tasks and channels, the primitives for (cooperative) concurrency in Teliva.
+    >
+    >We string together a cascade of tasks connected by channels. Every prime number gets a new task that prints the first incoming number, and then filters out multiples of it from the incoming channel.
+    >
+    >This approach has the advantage that we don't need to create an array of n numbers to compute primes less than n.
+    >
+    >However, we still need to create p tasks and p channels if there are p primes less than n. Probably not worth it, given tasks and channels are much larger than numbers. This is just a demo.
+    >
+    >The noticeable periodic pauses are perhaps due to garbage collection.