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2 files changed, 538 insertions, 0 deletions

diff --git a/pprint.lua b/pprint.lua
new file mode 100644
index 0000000..efb3e2e
--- /dev/null
+++ b/pprint.lua
@@ -0,0 +1,479 @@
+-- https://github.com/jagt/pprint.lua/blob/master/pprint.lua
+-- public domain
+
+local pprint = { VERSION = '0.1' }
+
+local depth = 1
+
+pprint.defaults = {
+    -- If set to number N, then limit table recursion to N deep.
+    depth_limit = false,
+    -- type display trigger, hide not useful datatypes by default
+    -- custom types are treated as table
+    show_nil = true,
+    show_boolean = true,
+    show_number = true,
+    show_string = true,
+    show_table = true,
+    show_function = false,
+    show_thread = false,
+    show_userdata = false,
+    -- additional display trigger
+    show_metatable = false,     -- show metatable
+    show_all = false,           -- override other show settings and show everything
+    use_tostring = false,       -- use __tostring to print table if available
+    filter_function = nil,      -- called like callback(value[,key, parent]), return truty value to hide
+    object_cache = 'local',     -- cache blob and table to give it a id, 'local' cache per print, 'global' cache
+                                -- per process, falsy value to disable (might cause infinite loop)
+    -- format settings
+    indent_size = 2,            -- indent for each nested table level
+    level_width = 80,           -- max width per indent level
+    wrap_string = true,         -- wrap string when it's longer than level_width
+    wrap_array = false,         -- wrap every array elements
+    sort_keys = true,           -- sort table keys
+}
+
+local TYPES = {
+    ['nil'] = 1, ['boolean'] = 2, ['number'] = 3, ['string'] = 4, 
+    ['table'] = 5, ['function'] = 6, ['thread'] = 7, ['userdata'] = 8
+}
+
+-- seems this is the only way to escape these, as lua don't know how to map char '\a' to 'a'
+local ESCAPE_MAP = {
+    ['\a'] = '\\a', ['\b'] = '\\b', ['\f'] = '\\f', ['\n'] = '\\n', ['\r'] = '\\r',
+    ['\t'] = '\\t', ['\v'] = '\\v', ['\\'] = '\\\\',
+}
+
+-- generic utilities
+local function escape(s)
+    s = s:gsub('([%c\\])', ESCAPE_MAP)
+    local dq = s:find('"') 
+    local sq = s:find("'")
+    if dq and sq then
+        return s:gsub('"', '\\"'), '"'
+    elseif sq then
+        return s, '"'
+    else
+        return s, "'"
+    end
+end
+
+local function is_plain_key(key)
+    return type(key) == 'string' and key:match('^[%a_][%a%d_]*$')
+end
+
+local CACHE_TYPES = {
+    ['table'] = true, ['function'] = true, ['thread'] = true, ['userdata'] = true
+}
+
+-- cache would be populated to be like:
+-- {
+--     function = { `fun1` = 1, _cnt = 1 }, -- object id
+--     table = { `table1` = 1, `table2` = 2, _cnt = 2 },
+--     visited_tables = { `table1` = 7, `table2` = 8  }, -- visit count
+-- }
+-- use weakrefs to avoid accidentall adding refcount
+local function cache_apperance(obj, cache, option)
+    if not cache.visited_tables then
+        cache.visited_tables = setmetatable({}, {__mode = 'k'})
+    end
+    local t = type(obj)
+
+    -- TODO can't test filter_function here as we don't have the ix and key,
+    -- might cause different results?
+    -- respect show_xxx and filter_function to be consistent with print results
+    if (not TYPES[t] and not option.show_table)
+        or (TYPES[t] and not option['show_'..t]) then
+        return
+    end
+
+    if CACHE_TYPES[t] or TYPES[t] == nil then
+        if not cache[t] then
+            cache[t] = setmetatable({}, {__mode = 'k'})
+            cache[t]._cnt = 0
+        end
+        if not cache[t][obj] then
+            cache[t]._cnt = cache[t]._cnt + 1
+            cache[t][obj] = cache[t]._cnt
+        end
+    end
+    if t == 'table' or TYPES[t] == nil then
+        if cache.visited_tables[obj] == false then
+            -- already printed, no need to mark this and its children anymore
+            return
+        elseif cache.visited_tables[obj] == nil then
+            cache.visited_tables[obj] = 1
+        else
+            -- visited already, increment and continue
+            cache.visited_tables[obj] = cache.visited_tables[obj] + 1
+            return
+        end
+        for k, v in pairs(obj) do
+            cache_apperance(k, cache, option)
+            cache_apperance(v, cache, option)
+        end
+        local mt = getmetatable(obj)
+        if mt and option.show_metatable then
+            cache_apperance(mt, cache, option)
+        end
+    end
+end
+
+-- makes 'foo2' < 'foo100000'. string.sub makes substring anyway, no need to use index based method
+local function str_natural_cmp(lhs, rhs)
+    while #lhs > 0 and #rhs > 0 do
+        local lmid, lend = lhs:find('%d+')
+        local rmid, rend = rhs:find('%d+')
+        if not (lmid and rmid) then return lhs < rhs end
+
+        local lsub = lhs:sub(1, lmid-1)
+        local rsub = rhs:sub(1, rmid-1)
+        if lsub ~= rsub then
+            return lsub < rsub
+        end
+        
+        local lnum = tonumber(lhs:sub(lmid, lend))
+        local rnum = tonumber(rhs:sub(rmid, rend))
+        if lnum ~= rnum then
+            return lnum < rnum
+        end
+
+        lhs = lhs:sub(lend+1)
+        rhs = rhs:sub(rend+1)
+    end
+    return lhs < rhs
+end
+
+local function cmp(lhs, rhs)
+    local tleft = type(lhs)
+    local tright = type(rhs)
+    if tleft == 'number' and tright == 'number' then return lhs < rhs end
+    if tleft == 'string' and tright == 'string' then return str_natural_cmp(lhs, rhs) end
+    if tleft == tright then return str_natural_cmp(tostring(lhs), tostring(rhs)) end
+
+    -- allow custom types
+    local oleft = TYPES[tleft] or 9
+    local oright = TYPES[tright] or 9
+    return oleft < oright
+end
+
+-- setup option with default
+local function make_option(option)
+    if option == nil then
+        option = {}
+    end
+    for k, v in pairs(pprint.defaults) do
+        if option[k] == nil then
+            option[k] = v
+        end
+        if option.show_all then
+            for t, _ in pairs(TYPES) do
+                option['show_'..t] = true
+            end
+            option.show_metatable = true
+        end
+    end
+    return option
+end
+
+-- override defaults and take effects for all following calls
+function pprint.setup(option)
+    pprint.defaults = make_option(option)
+end
+
+-- format lua object into a string
+function pprint.pformat(obj, option, printer)
+    option = make_option(option)
+    local buf = {}
+    local function default_printer(s)
+        table.insert(buf, s)
+    end
+    printer = printer or default_printer
+
+    local cache
+    if option.object_cache == 'global' then
+        -- steal the cache into a local var so it's not visible from _G or anywhere
+        -- still can't avoid user explicitly referentce pprint._cache but it shouldn't happen anyway
+        cache = pprint._cache or {}
+        pprint._cache = nil
+    elseif option.object_cache == 'local' then
+        cache = {}
+    end
+
+    local last = '' -- used for look back and remove trailing comma
+    local status = {
+        indent = '', -- current indent
+        len = 0,     -- current line length
+    }
+
+    local wrapped_printer = function(s)
+        printer(last)
+        last = s
+    end
+
+    local function _indent(d)
+        status.indent = string.rep(' ', d + #(status.indent))
+    end
+
+    local function _n(d)
+        wrapped_printer('\n')
+        wrapped_printer(status.indent)
+        if d then
+            _indent(d)
+        end
+        status.len = 0
+        return true -- used to close bracket correctly
+    end
+
+    local function _p(s, nowrap)
+        status.len = status.len + #s
+        if not nowrap and status.len > option.level_width then
+            _n()
+            wrapped_printer(s)
+            status.len = #s
+        else
+            wrapped_printer(s)
+        end
+    end
+
+    local formatter = {}
+    local function format(v)
+        local f = formatter[type(v)]
+        f = f or formatter.table -- allow patched type()
+        if option.filter_function and option.filter_function(v, nil, nil) then
+            return ''
+        else
+            return f(v)
+        end
+    end
+
+    local function tostring_formatter(v)
+        return tostring(v)
+    end
+
+    local function number_formatter(n)
+        return n == math.huge and '[[math.huge]]' or tostring(n)
+    end
+
+    local function nop_formatter(v)
+        return ''
+    end
+
+    local function make_fixed_formatter(t, has_cache)
+        if has_cache then
+            return function (v)
+                return string.format('[[%s %d]]', t, cache[t][v])
+            end
+        else
+            return function (v)
+                return '[['..t..']]'
+            end
+        end
+    end
+
+    local function string_formatter(s, force_long_quote)
+        local s, quote = escape(s)
+        local quote_len = force_long_quote and 4 or 2
+        if quote_len + #s + status.len > option.level_width then
+            _n()
+            -- only wrap string when is longer than level_width
+            if option.wrap_string and #s + quote_len > option.level_width then
+                -- keep the quotes together
+                _p('[[')
+                while #s + status.len >= option.level_width do
+                    local seg = option.level_width - status.len
+                    _p(string.sub(s, 1, seg), true)
+                    _n()
+                    s = string.sub(s, seg+1)
+                end
+                _p(s) -- print the remaining parts
+                return ']]' 
+            end
+        end
+
+        return force_long_quote and '[['..s..']]' or quote..s..quote
+    end
+
+    local function table_formatter(t)
+        if option.use_tostring then
+            local mt = getmetatable(t)
+            if mt and mt.__tostring then
+                -- return string_formatter(tostring(t), true)
+                return tostring(t)
+            end
+        end
+
+        local print_header_ix = nil
+        local ttype = type(t)
+        if option.object_cache then
+            local cache_state = cache.visited_tables[t]
+            local tix = cache[ttype][t]
+            -- FIXME should really handle `cache_state == nil`
+            -- as user might add things through filter_function
+            if cache_state == false then
+                -- already printed, just print the the number
+                return string_formatter(string.format('%s %d', ttype, tix), true)
+            elseif cache_state > 1 then
+                -- appeared more than once, print table header with number
+                print_header_ix = tix
+                cache.visited_tables[t] = false
+            else
+                -- appeared exactly once, print like a normal table
+            end
+        end
+
+        local limit = tonumber(option.depth_limit)
+        if limit and depth > limit then
+           if print_header_ix then
+              return string.format('[[%s %d]]...', ttype, print_header_ix)
+           end
+           return string_formatter(tostring(t), true)
+        end
+
+        local tlen = #t
+        local wrapped = false
+        _p('{')
+        _indent(option.indent_size)
+        _p(string.rep(' ', option.indent_size - 1))
+        if print_header_ix then
+            _p(string.format('--[[%s %d]] ', ttype, print_header_ix))
+        end
+        for ix = 1,tlen do
+            local v = t[ix]
+            if formatter[type(v)] == nop_formatter or 
+               (option.filter_function and option.filter_function(v, ix, t)) then
+               -- pass
+            else
+                if option.wrap_array then
+                    wrapped = _n()
+                end
+                depth = depth+1
+                _p(format(v)..', ')
+                depth = depth-1
+            end
+        end
+
+        -- hashmap part of the table, in contrast to array part
+        local function is_hash_key(k)
+            if type(k) ~= 'number' then
+                return true
+            end
+
+            local numkey = math.floor(tonumber(k))
+            if numkey ~= k or numkey > tlen or numkey <= 0 then
+                return true
+            end
+        end
+
+        local function print_kv(k, v, t)
+            -- can't use option.show_x as obj may contain custom type
+            if formatter[type(v)] == nop_formatter or
+               formatter[type(k)] == nop_formatter or 
+               (option.filter_function and option.filter_function(v, k, t)) then
+                return
+            end
+            wrapped = _n()
+            if is_plain_key(k) then
+                _p(k, true)
+            else
+                _p('[')
+                -- [[]] type string in key is illegal, needs to add spaces inbetween
+                local k = format(k)
+                if string.match(k, '%[%[') then
+                    _p(' '..k..' ', true)
+                else
+                    _p(k, true)
+                end
+                _p(']')
+            end
+            _p(' = ', true)
+            depth = depth+1
+            _p(format(v), true)
+            depth = depth-1
+            _p(',', true)
+        end
+
+        if option.sort_keys then
+            local keys = {}
+            for k, _ in pairs(t) do
+                if is_hash_key(k) then
+                    table.insert(keys, k)
+                end
+            end
+            table.sort(keys, cmp)
+            for _, k in ipairs(keys) do
+                print_kv(k, t[k], t)
+            end
+        else
+            for k, v in pairs(t) do
+                if is_hash_key(k) then
+                    print_kv(k, v, t)
+                end
+            end
+        end
+
+        if option.show_metatable then
+            local mt = getmetatable(t)
+            if mt then
+                print_kv('__metatable', mt, t)
+            end
+        end
+
+        _indent(-option.indent_size)
+        -- make { } into {}
+        last = string.gsub(last, '^ +$', '')
+        -- peek last to remove trailing comma
+        last = string.gsub(last, ',%s*$', ' ')
+        if wrapped then
+            _n()
+        end
+        _p('}')
+
+        return ''
+    end
+
+    -- set formatters
+    formatter['nil'] = option.show_nil and tostring_formatter or nop_formatter
+    formatter['boolean'] = option.show_boolean and tostring_formatter or nop_formatter
+    formatter['number'] = option.show_number and number_formatter or nop_formatter -- need to handle math.huge
+    formatter['function'] = option.show_function and make_fixed_formatter('function', option.object_cache) or nop_formatter
+    formatter['thread'] = option.show_thread and make_fixed_formatter('thread', option.object_cache) or nop_formatter
+    formatter['userdata'] = option.show_userdata and make_fixed_formatter('userdata', option.object_cache) or nop_formatter
+    formatter['string'] = option.show_string and string_formatter or nop_formatter
+    formatter['table'] = option.show_table and table_formatter or nop_formatter
+
+    if option.object_cache then
+        -- needs to visit the table before start printing
+        cache_apperance(obj, cache, option)
+    end
+
+    _p(format(obj))
+    printer(last) -- close the buffered one
+
+    -- put cache back if global
+    if option.object_cache == 'global' then
+        pprint._cache = cache
+    end
+
+    return table.concat(buf)
+end
+
+-- pprint all the arguments
+function pprint.pprint( ... )
+    local args = {...}
+    -- select will get an accurate count of array len, counting trailing nils
+    local len = select('#', ...)
+    for ix = 1,len do
+        pprint.pformat(args[ix], nil, io.write)
+        io.write('\n')
+    end
+end
+
+setmetatable(pprint, {
+    __call = function (_, ...)
+        pprint.pprint(...)
+    end
+})
+
+return pprint
+
diff --git a/repl.lua b/repl.lua
new file mode 100644
index 0000000..911e7c7
--- /dev/null
+++ b/repl.lua
@@ -0,0 +1,59 @@
+local pprint=require"pprint"
+pprint.setup{show_all=true,use_tostring=true}
+
+local repl_env = {}
+
+-- should use loadstring on 5.1
+-- works on luajit though
+local function load_chunk(s)
+	return load(s,"repl","t")
+end
+
+local function prompt(p)
+	io.write(p)
+	return io.read()
+end
+
+local function read_chunk()
+	-- try with return
+	-- if that doesn't work try without return
+	-- if error ends in <eof> try multiline
+
+	local function try(text)
+		local f, err = load_chunk("return "..text..";")
+		if f then return f end
+
+		local f, err = load_chunk(text)
+		if f then return f end
+
+		if err:sub(-5) == "<eof>" or err:sub(-7) == "'<eof>'" then
+			local nt = text.."\n"..prompt("} ")
+			return try(nt)
+		end
+
+		return f, err
+	end
+	return try(prompt("] "))
+end
+
+local function result(ok,...)
+	if ok then
+		pprint(...)
+	else
+		print("error: "..(...))
+	end
+end
+
+local function msgh(e)
+	return debug.traceback(e,1)
+end
+
+while true do
+	local f,err = read_chunk()
+
+	if not f then
+		print("load error: "..err)
+	else
+		result(xpcall(f,msgh))
+	end
+end