mjf · January 17, 2025 11:49 · Jan 17, 2025 · Jan 17, 2025
diff --git a/radix_fun.lua b/radix_fun.lua
@@ -140,7 +140,6 @@ local function assert_eq(actual, expected, message)
       success = actual == expected
     end
   end
-
   if not success then
     error(
       "Assertion failed: " ..  message .. "\n" ..

diff --git a/radix_fun.lua b/radix_fun.lua
@@ -0,0 +1,214 @@
+local function from_radix(digits, base)
+  local ip = 0
+  local fp = 0
+  local dp = nil
+  for i, v in ipairs(digits) do
+    if v == "." then
+      dp = i
+      break
+    end
+    if type(v) ~= "number" then
+      error("Invalid digit in input")
+    end
+    if v < 0 or v >= base then
+      error("Digit out of range for given base")
+    end
+  end
+  if dp then
+    for i = 1, dp - 1 do
+      ip = ip * base + digits[i]
+    end
+    for i = dp + 1, #digits do
+      fp = fp + digits[i] / (base ^ (i - dp))
+    end
+  else
+    for i = 1, #digits do
+      ip = ip * base + digits[i]
+    end
+  end
+  return ip + fp
+end
+
+local function to_radix(x, base, frac_digits)
+  if base < 2 then
+    error("Base must be at least 2")
+  end
+  if frac_digits and frac_digits < 0 then
+    error("Number of fractional digits must be non-negative")
+  end
+  local result = {}
+  local ip = math.floor(x)
+  local fp = x - ip
+  repeat
+    table.insert(result, 1, ip % base)
+    ip = math.floor(ip / base)
+  until ip == 0
+  if frac_digits and frac_digits > 0 then
+    table.insert(result, ".")
+    for _ = 1, frac_digits do
+      fp = fp * base
+      local digit = math.floor(fp)
+      table.insert(result, digit)
+      fp = fp - digit
+    end
+  end
+  return result
+end
+
+local function clock_from_moment(tee)
+  local seconds = math.fmod(tee, 86400)
+  if seconds < 0 then
+    seconds = seconds + 86400
+  end
+  local hours = math.floor(seconds / 3600)
+  seconds = math.fmod(seconds, 3600)
+  local minutes = math.floor(seconds / 60)
+  seconds = math.fmod(seconds, 60)
+  return {hours, minutes, math.floor(seconds)}
+end
+
+local function time_from_clock(hms)
+  if #hms ~= 3 then
+    error("Clock time must have 3 elements: {hours, minutes, seconds}")
+  end
+  for _, v in ipairs(hms) do
+    if type(v) ~= "number" then
+      error("Clock time elements must be numbers")
+    end
+  end
+  if hms[1] < 0 or hms[1] > 23 then
+    error("Hours must be between 0 and 23")
+  end
+  if hms[2] < 0 or hms[2] > 59 then
+    error("Minutes must be between 0 and 59")
+  end
+  if hms[3] < 0 or hms[3] > 59 then
+    error("Seconds must be between 0 and 59")
+  end
+  return ((hms[1] * 3600) + (hms[2] * 60) + hms[3]) / 86400
+end
+
+local function table_tostring(t)
+  if type(t) ~= "table" then
+    return tostring(t)
+  end
+  local s = "{"
+  for k, v in pairs(t) do
+    s = s .. "[" .. tostring(k) .. "] = " .. tostring(v) .. ", "
+  end
+  if #s > 1 then
+    s = s:sub(1, #s - 2)
+  end
+  return s .. "}"
+end
+
+local function float_equal(a, b, tolerance)
+  tolerance = tolerance or 1e-9
+  return math.abs(a - b) < tolerance
+end
+
+local function assert_eq(actual, expected, message)
+  local success = false
+  if type(actual) == type(expected) then
+    if type(actual) == "table" then
+      local actual_count = 0
+      local expected_count = 0
+      for _ in pairs(actual) do
+        actual_count = actual_count + 1
+      end
+      for _ in pairs(expected) do
+        expected_count = expected_count + 1
+      end
+      if actual_count == expected_count then
+        success = true
+        for k, exp_v in pairs(expected) do
+          local v = actual[k]
+          if type(v) == "number" and type(exp_v) == "number" then
+            if not float_equal(v, exp_v) then
+              success = false
+              break
+            end
+          elseif tostring(v) ~= tostring(exp_v) then
+            success = false
+            break
+          end
+        end
+      end
+    elseif type(actual) == "number" then
+      success = float_equal(actual, expected)
+    else
+      success = actual == expected
+    end
+  end
+
+  if not success then
+    error(
+      "Assertion failed: " ..  message .. "\n" ..
+      "Expected: " .. table_tostring(expected) .. "\n" ..
+      "Got: " .. table_tostring(actual)
+    )
+  end
+end
+
+local tests = {
+  {function()
+    return from_radix({1, 0, 1, ".", 1, 1}, 2)
+  end, 5.75, "Binary 101.11"},
+  {function()
+    return to_radix(5.75, 2, 5)
+  end, {1, 0, 1, ".", 1, 1, 0, 0, 0}, "Decimal 5.75 to binary"},
+  {function()
+    return to_radix(12345, 16)
+  end, {3, 0, 3, 9}, "Decimal 12345 to hex"},
+  {function()
+    return to_radix(0.3, 2, 10)
+  end, {0, ".", 0, 1, 0, 0, 1, 1, 0, 0, 1, 1}, "Decimal 0.3 to binary"},
+  {function()
+    return clock_from_moment(3723)
+  end, {1, 2, 3}, "3723 seconds to clock time"},
+  {function()
+    return clock_from_moment(0)
+  end, {0, 0, 0}, "0 seconds to clock time"},
+  {function()
+    return clock_from_moment(86400)
+  end, {0, 0, 0}, "86400 seconds to clock time"},
+  {function()
+    return clock_from_moment(86461)
+  end, {0, 1, 1}, "86461 seconds to clock time"},
+  {function()
+    return clock_from_moment(123456)
+  end, {10, 17, 36}, "123456 seconds to clock time"},
+  {function()
+    return time_from_clock({1, 2, 3})
+  end, 0.043090277777778, "Clock time 1:2:3 to fraction of day"},
+  {function()
+    return time_from_clock({0, 0, 0})
+  end, 0, "Clock time 0:0:0 to fraction of day"},
+  {function()
+    return time_from_clock({12, 0, 0})
+  end, 0.5, "Clock time 12:0:0 to fraction of day"},
+  {function()
+    return time_from_clock({23, 59, 59})
+  end, 0.99998842592593, "Clock time 23:59:59 to fraction of day"},
+  {function()
+    return time_from_clock({1, 10, 56})
+  end, 0.049259259259259, "Clock time 1:10:56 to fraction of day"}
+}
+
+local function run_tests()
+  local passed = 0
+  local total = #tests
+
+  for i, test in ipairs(tests) do
+    local description = test[3]
+    local actual = test[1]()
+    local expected = test[2]
+    assert_eq(actual, expected, description)
+    print("Test " .. i .. ": " .. description .. " - PASSED")
+    passed = passed + 1
+  end
+
+  print("\nPassed " .. passed .. " of " .. total .. " tests.")
+end
+
+run_tests()