Added vulgar_fraction function, and increased resilience.

number.lua

@@ -1,6 +1,10 @@
 
 local utf8 = require "utf8" -- FIXME: I don't really like this. Either have a local copy of the files, or remove the functionallity requiring it.
 
+-- Make sure we imported the correct library.
+local CAN_USE_SHORTHAND = not not utf8.width
+if not CAN_USE_SHORTHAND then  utf8.width = function(a) return #a end  end
+
 -- Constants
 
 local MAXIMUM_INT  = 2^53    -- The maximum double for where all integers can be represented exactly.
@@ -9,6 +13,11 @@ local MAXIMUM_ZERO = 10^-7   -- Used when attempting to determine fraction. Anyt
 --------------------------------------------------------------------------------
 -- Util
 
+local function vulgar_fraction (a, b)
+	-- Returns a string representing the fraction a/b, with unicode characters.
+	return utf8.superscript(a) .. '⁄' .. utf8.subscript(b)
+end
+
 local function is_integer (n)
 	-- Predicate. Neither +inf, -inf nor nan are integer.
 	return  n == math.floor(n)  and n ~= 1/0 and n ~= -1/0
@@ -68,8 +77,8 @@ local SPECIAL_NUMBER = {
 	-- x = a/b
 	{ est   = calculate_fraction,
 	  real  = function (a, b) return b ~= 1 and (a/b)                       end,
-	  repr  = function (a, b) return format_num(a)..'/'..format_num(b)      end,
+	  repr  = function (a, b) return a..'/'..b                              end,
-	  short = function (a, b) return format_num(a)..'/'..format_num(b)      end,
+	  short = function (a, b) return a..'/'..b                              end,
     },
 	-- Factorial
 	{ est   = function (n) return inverse_factorial(n)                      end,
@@ -155,5 +164,5 @@ end
 
 return function (value, options, depth, l)
 	-- TODO: Add support for more relaxed representations.
-	l[#l+1] = format_num(value, options.math_shorthand)
+	l[#l+1] = format_num(value, CAN_USE_SHORTHAND and options.math_shorthand)
 end

pretty.lua

@@ -5,18 +5,25 @@
 local format_number, format_function, analyze_structure, get_table_info, TABLE_TYPE
 do
     local thispath = ... and select('1', ...):match('.+%.') or ''
+    local function import (name, ignore_failure)
+        local was_loaded, lib_or_error      =  pcall(require, thispath..name)
+        if not was_loaded then
+            if ignore_failure then  return nil  end
+            error('[pretty]: Could not load vital library: '..name..'.lua:\n\t'..lib_or_error)
+        end
+        return lib_or_error
+    end
 
     -- Load number and function formatting
-    format_number      =  select(2, pcall(require, thispath..'number'))
+    -- Will use a very simple number formatting, if number.lua is not available.
-    format_function    =  select(2, pcall(require, thispath..'function'))
+    -- Will use a very simple function formatting, if function.lua is not available.
+    format_number      =  import('number',   true)  or  function (value, _, _, l)  l[#l+1]  =  tostring(value)  end
+    format_function    =  import('function', true)  or  function (value, _, _, l)  l[#l+1]  =  'function (...) --[['..tostring(value):sub(11)..']] end'  end
 
     -- Load other stuff
-    local was_loaded
+    analyze_structure  =  import 'analyze_structure'
-    was_loaded, analyze_structure  =  pcall(require, thispath..'analyze_structure')
     analyze_structure, get_table_info  =  analyze_structure[1], analyze_structure[2]
-    assert(was_loaded, '[pretty]: Could not load vital library: analyze_structure')
+    TABLE_TYPE         =  import 'table_type'
-    was_loaded, TABLE_TYPE         =  pcall(require, thispath..'table_type')
-    assert(was_loaded, '[pretty]: Could not load vital library: table_type')
 end
 --
 
@@ -431,13 +438,6 @@ local function format_string (str, options, depth, l)
     l[#l+1] = right
 end
 
-if not format_number then
-    -- Very simple number formatting, if number.lua is not available.
-    format_number = function (value, _, _, l)
-        l[#l+1]  =  tostring(value)
-    end
-end
-
 local function format_coroutine (value, options, depth, l)
     l[#l+1] = coroutine.status(value)
     l[#l+1] = ' coroutine: '
@@ -448,13 +448,6 @@ local function format_primitive (value, options, depth, l)
     l[#l+1] = tostring(value)
 end
 
-if not format_function then
-    -- Very simple function formatting, if function.lua is not available.
-    format_function = function (value, _, _, l)
-        l[#l+1]  =  'function (...) --[['..tostring(value):sub(11)..']] end'
-    end
-end
-
 local TYPE_TO_FORMAT_FUNC = {
     ['nil']      =  format_primitive,
     ['boolean']  =  format_primitive,

test/test_resilience.lua

@@ -42,6 +42,14 @@ SUITE:addTest('Dont allow bad types in options', function ()
 end)
 
 --------------------------------------------------------------------------------
+-- Survive not loading libs
+
+
+-- TODO: Find a way to test this.
+
+
+--------------------------------------------------------------------------------
+-- Strange standard libs
 
 SUITE:addTest('no_std_lib', function ()
     -- This tests whether one could load the library with an empty env, without