From 026413831cdd62a4edb738a642cbbb7da44cfc84 Mon Sep 17 00:00:00 2001
From: mpeterv <mpeterval@gmail.com>
Date: Thu, 10 Sep 2015 21:49:41 +0300
Subject: [PATCH] Do not use setfenv in markdown.lua

Use local variables instead.
---
 markdown.lua | 206 +++++++++++++++++++++++++--------------------------
 1 file changed, 100 insertions(+), 106 deletions(-)

diff --git a/markdown.lua b/markdown.lua
index 87de924..2de8b09 100644
--- a/markdown.lua
+++ b/markdown.lua
@@ -116,13 +116,6 @@ THE SOFTWARE.
 // Niklas
 ]]
 
-
--- Set up a table for holding local functions to avoid polluting the global namespace
-local M = {}
-local MT = {__index = _G}
-setmetatable(M, MT)
-setfenv(1, M)
-
 ----------------------------------------------------------------------
 -- Utility functions
 ----------------------------------------------------------------------
@@ -130,8 +123,8 @@ setfenv(1, M)
 -- Locks table t from changes, writes an error if someone attempts to change the table.
 -- This is useful for detecting variables that have "accidently" been made global. Something
 -- I tend to do all too much.
-function lock(t)
-   function lock_new_index(t, k, v)
+local function lock(t)
+   local function lock_new_index(t, k, v)
       error("module has been locked -- " .. k .. " must be declared local", 2)
    end
 
@@ -141,20 +134,20 @@ function lock(t)
 end
 
 -- Returns the result of mapping the values in table t through the function f
-function map(t, f)
+local function map(t, f)
    local out = {}
    for k,v in pairs(t) do out[k] = f(v,k) end
    return out
 end
 
 -- The identity function, useful as a placeholder.
-function identity(text) return text end
+local function identity(text) return text end
 
 -- Functional style if statement. (NOTE: no short circuit evaluation)
-function iff(t, a, b) if t then return a else return b end end
+local function iff(t, a, b) if t then return a else return b end end
 
 -- Splits the text into an array of separate lines.
-function split(text, sep)
+local function split(text, sep)
    sep = sep or "\n"
    local lines = {}
    local pos = 1
@@ -168,7 +161,7 @@ function split(text, sep)
 end
 
 -- Converts tabs to spaces
-function detab(text)
+local function detab(text)
    local tab_width = 4
    local function rep(match)
       local spaces = -match:len()
@@ -180,7 +173,7 @@ function detab(text)
 end
 
 -- Applies string.find for every pattern in the list and returns the first match
-function find_first(s, patterns, index)
+local function find_first(s, patterns, index)
    local res = {}
    for _,p in ipairs(patterns) do
       local match = {s:find(p, index)}
@@ -192,7 +185,7 @@ end
 -- If a replacement array is specified, the range [start, stop] in the array is replaced
 -- with the replacement array and the resulting array is returned. Without a replacement
 -- array the section of the array between start and stop is returned.
-function splice(array, start, stop, replacement)
+local function splice(array, start, stop, replacement)
    if replacement then
       local n = stop - start + 1
       while n > 0 do
@@ -213,7 +206,7 @@ function splice(array, start, stop, replacement)
 end
 
 -- Outdents the text one step.
-function outdent(text)
+local function outdent(text)
    text = "\n" .. text
    text = text:gsub("\n  ? ? ?", "\n")
    text = text:sub(2)
@@ -221,7 +214,7 @@ function outdent(text)
 end
 
 -- Indents the text one step.
-function indent(text)
+local function indent(text)
    text = text:gsub("\n", "\n    ")
    return text
 end
@@ -229,7 +222,7 @@ end
 -- Does a simple tokenization of html data. Returns the data as a list of tokens. 
 -- Each token is a table with a type field (which is either "tag" or "text") and
 -- a text field (which contains the original token data).
-function tokenize_html(html)
+local function tokenize_html(html)
    local tokens = {}
    local pos = 1
    while true do
@@ -287,7 +280,7 @@ local HASH = {
 
 -- Inits hashing. Creates a hash_identifier that doesn't occur anywhere
 -- in the text.
-function init_hash(text)
+local function init_hash(text)
    HASH.inited = true
    HASH.identifier = ""
    HASH.counter = 0
@@ -305,7 +298,7 @@ function init_hash(text)
 end
 
 -- Returns the hashed value for s.
-function hash(s)
+local function hash(s)
    assert(HASH.inited)
    if not HASH.table[s] then
       HASH.counter = HASH.counter + 1
@@ -342,18 +335,18 @@ local PD = {
 --        Nested data.
 --     </div>
 -- </div>
-function block_pattern(tag)
+local function block_pattern(tag)
    return "\n<" .. tag .. ".-\n</" .. tag .. ">[ \t]*\n"
 end
 
 -- Pattern for matching a block tag that begins and ends with a newline
-function line_pattern(tag)
+local function line_pattern(tag)
    return "\n<" .. tag .. ".-</" .. tag .. ">[ \t]*\n"
 end
 
 -- Protects the range of characters from start to stop in the text and
 -- returns the protected string.
-function protect_range(text, start, stop)
+local function protect_range(text, start, stop)
    local s = text:sub(start, stop)
    local h = hash(s)
    PD.blocks[h] = s
@@ -363,7 +356,7 @@ end
 
 -- Protect every part of the text that matches any of the patterns. The first
 -- matching pattern is protected first, etc.
-function protect_matches(text, patterns)
+local function protect_matches(text, patterns)
    while true do
       local start, stop = find_first(text, patterns)
       if not start then break end
@@ -373,7 +366,7 @@ function protect_matches(text, patterns)
 end
 
 -- Protects blocklevel tags in the specified text
-function protect(text)
+local function protect(text)
    -- First protect potentially nested block tags
    text = protect_matches(text, map(PD.tags, block_pattern))
    -- Then protect block tags at the line level.
@@ -385,12 +378,12 @@ function protect(text)
 end
 
 -- Returns true if the string s is a hash resulting from protection
-function is_protected(s)
+local function is_protected(s)
    return PD.blocks[s]
 end
 
 -- Unprotects the specified text by expanding all the nonces
-function unprotect(text)
+local function unprotect(text)
    for k,v in pairs(PD.blocks) do
       v = v:gsub("%%", "%%%%")
       text = text:gsub(k, v)
@@ -410,14 +403,14 @@ end
 -- Returns true if the line is a ruler of (char) characters.
 -- The line must contain at least three char characters and contain only spaces and
 -- char characters.
-function is_ruler_of(line, char)
+local function is_ruler_of(line, char)
    if not line:match("^[ %" .. char .. "]*$") then return false end
    if not line:match("%" .. char .. ".*%" .. char .. ".*%" .. char) then return false end
    return true
 end
 
 -- Identifies the block level formatting present in the line
-function classify(line)
+local function classify(line)
    local info = {line = line, text = line}
    
    if line:match("^    ") then
@@ -483,7 +476,7 @@ end
 
 -- Find headers constisting of a normal line followed by a ruler and converts them to
 -- header entries.
-function headers(array)
+local function headers(array)
    local i = 1
    while i <= #array - 1 do
       if array[i].type  == "normal" and array[i+1].type == "ruler" and 
@@ -500,8 +493,45 @@ function headers(array)
    return array
 end
 
+-- Forward declarations
+local block_transform, span_transform, encode_code
+
+-- Convert lines to html code
+local function blocks_to_html(lines, no_paragraphs)
+   local out = {}
+   local i = 1
+   while i <= #lines do
+      local line = lines[i]
+      if line.type == "ruler" then
+         table.insert(out, "<hr/>")
+      elseif line.type == "raw" then
+         table.insert(out, line.html)
+      elseif line.type == "normal" then
+         local s = line.line
+         
+         while i+1 <= #lines and lines[i+1].type == "normal" do
+            i = i + 1
+            s = s .. "\n" .. lines[i].line
+         end
+         
+         if no_paragraphs then
+            table.insert(out, span_transform(s))
+         else
+            table.insert(out, "<p>" .. span_transform(s) .. "</p>")
+         end
+      elseif line.type == "header" then
+         local s = "<h" .. line.level .. ">" .. span_transform(line.text) .. "</h" .. line.level .. ">"
+         table.insert(out, s)
+      else
+         table.insert(out, line.line)
+      end
+      i = i + 1
+   end
+   return out
+end
+
 -- Find list blocks and convert them to protected data blocks
-function lists(array, sublist)
+local function lists(array, sublist)
    local function process_list(arr)
       local function any_blanks(arr)
          for i = 1, #arr do
@@ -624,7 +654,7 @@ function lists(array, sublist)
 end
 
 -- Find and convert blockquote markers.
-function blockquotes(lines)
+local function blockquotes(lines)
    local function find_blockquote(lines)
       local start
       for i,line in ipairs(lines) do
@@ -674,7 +704,7 @@ function blockquotes(lines)
 end
 
 -- Find and convert codeblocks.
-function codeblocks(lines)
+local function codeblocks(lines)
    local function find_codeblock(lines)
       local start
       for i,line in ipairs(lines) do
@@ -715,40 +745,6 @@ function codeblocks(lines)
    return lines
 end
 
--- Convert lines to html code
-function blocks_to_html(lines, no_paragraphs)
-   local out = {}
-   local i = 1
-   while i <= #lines do
-      local line = lines[i]
-      if line.type == "ruler" then
-         table.insert(out, "<hr/>")
-      elseif line.type == "raw" then
-         table.insert(out, line.html)
-      elseif line.type == "normal" then
-         local s = line.line
-         
-         while i+1 <= #lines and lines[i+1].type == "normal" do
-            i = i + 1
-            s = s .. "\n" .. lines[i].line
-         end
-         
-         if no_paragraphs then
-            table.insert(out, span_transform(s))
-         else
-            table.insert(out, "<p>" .. span_transform(s) .. "</p>")
-         end
-      elseif line.type == "header" then
-         local s = "<h" .. line.level .. ">" .. span_transform(line.text) .. "</h" .. line.level .. ">"
-         table.insert(out, s)
-      else
-         table.insert(out, line.line)
-      end
-      i = i + 1
-   end
-   return out
-end
-
 -- Perform all the block level transforms
 function block_transform(text, sublist)
    local lines = split(text)
@@ -764,7 +760,7 @@ end
 
 -- Debug function for printing a line array to see the result
 -- of partial transforms.
-function print_lines(lines)
+local function print_lines(lines)
    for i, line in ipairs(lines) do
       print(i, line.type, line.text or line.line)
    end
@@ -778,10 +774,10 @@ end
 
 -- These characters may need to be escaped because they have a special
 -- meaning in markdown.
-escape_chars = "'\\`*_{}[]()>#+-.!'"
-escape_table = {}
+local escape_chars = "'\\`*_{}[]()>#+-.!'"
+local escape_table = {}
 
-function init_escape_table()
+local function init_escape_table()
    escape_table = {}
    for i = 1,#escape_chars do
       local c = escape_chars:sub(i,i)
@@ -790,15 +786,24 @@ function init_escape_table()
 end
 
 -- Adds a new escape to the escape table.
-function add_escape(text)
+local function add_escape(text)
    if not escape_table[text] then
       escape_table[text] = hash(text)
    end
    return escape_table[text]
-end   
+end
+
+-- Encode backspace-escaped characters in the markdown source.
+local function encode_backslash_escapes(t)
+   for i=1,escape_chars:len() do
+      local c = escape_chars:sub(i,i)
+      t = t:gsub("\\%" .. c, escape_table[c])
+   end
+   return t
+end
 
 -- Escape characters that should not be disturbed by markdown.
-function escape_special_chars(text)
+local function escape_special_chars(text)
    local tokens = tokenize_html(text)
    
    local out = ""
@@ -816,17 +821,8 @@ function escape_special_chars(text)
    return out
 end
 
--- Encode backspace-escaped characters in the markdown source.
-function encode_backslash_escapes(t)
-   for i=1,escape_chars:len() do
-      local c = escape_chars:sub(i,i)
-      t = t:gsub("\\%" .. c, escape_table[c])
-   end
-   return t
-end
-
 -- Unescape characters that have been encoded.
-function unescape_special_chars(t)
+local function unescape_special_chars(t)
    local tin = t
    for k,v in pairs(escape_table) do
       k = k:gsub("%%", "%%%%")
@@ -850,7 +846,7 @@ function encode_code(s)
 end
 
 -- Handle backtick blocks.
-function code_spans(s)
+local function code_spans(s)
    s = s:gsub("\\\\", escape_table["\\"])
    s = s:gsub("\\`", escape_table["`"])
 
@@ -880,7 +876,7 @@ function code_spans(s)
 end
 
 -- Encode alt text... enodes &, and ".
-function encode_alt(s)
+local function encode_alt(s)
    if not s then return s end
    s = s:gsub('&', '&amp;')
    s = s:gsub('"', '&quot;')
@@ -888,8 +884,11 @@ function encode_alt(s)
    return s
 end
 
+-- Forward declaration for link_db as returned by strip_link_definitions.
+local link_database
+
 -- Handle image references
-function images(text)
+local function images(text)
    local function reference_link(alt, id)
       alt = encode_alt(alt:match("%b[]"):sub(2,-2))
       id = id:match("%[(.*)%]"):lower()
@@ -922,7 +921,7 @@ function images(text)
 end
 
 -- Handle anchor references
-function anchors(text)
+local function anchors(text)
    local function reference_link(text, id)
       text = text:match("%b[]"):sub(2,-2)
       id = id:match("%b[]"):sub(2,-2):lower()
@@ -955,7 +954,7 @@ function anchors(text)
 end
 
 -- Handle auto links, i.e. <http://www.google.com/>.
-function auto_links(text)
+local function auto_links(text)
    local function link(s)
       return add_escape("<a href=\"" .. s .. "\">") .. s .. "</a>"
    end
@@ -1004,7 +1003,7 @@ end
 
 -- Encode free standing amps (&) and angles (<)... note that this does not
 -- encode free >.
-function amps_and_angles(s)
+local function amps_and_angles(s)
    -- encode amps not part of &..; expression
    local pos = 1
    while true do
@@ -1029,7 +1028,7 @@ function amps_and_angles(s)
 end
 
 -- Handles emphasis markers (* and _) in the text.
-function emphasis(text)
+local function emphasis(text)
    for _, s in ipairs {"%*%*", "%_%_"} do
       text = text:gsub(s .. "([^%s][%*%_]?)" .. s, "<strong>%1</strong>")
       text = text:gsub(s .. "([^%s][^<>]-[^%s][%*%_]?)" .. s, "<strong>%1</strong>")
@@ -1044,7 +1043,7 @@ function emphasis(text)
 end
 
 -- Handles line break markers in the text.
-function line_breaks(text)
+local function line_breaks(text)
    return text:gsub("  +\n", " <br/>\n")
 end
 
@@ -1067,7 +1066,7 @@ end
 
 -- Cleanup the text by normalizing some possible variations to make further
 -- processing easier.
-function cleanup(text)
+local function cleanup(text)
    -- Standardize line endings
    text = text:gsub("\r\n", "\n")  -- DOS to UNIX
    text = text:gsub("\r", "\n")    -- Mac to UNIX
@@ -1086,7 +1085,7 @@ function cleanup(text)
 end
 
 -- Strips link definitions from the text and stores the data in a lookup table.
-function strip_link_definitions(text)
+local function strip_link_definitions(text)
    local linkdb = {}
    
    local function link_def(id, url, title)
@@ -1109,10 +1108,8 @@ function strip_link_definitions(text)
    return text, linkdb
 end
 
-link_database = {}
-
 -- Main markdown processing function
-function markdown(text)
+local function markdown(text)
    init_hash(text)
    init_escape_table()
    
@@ -1128,11 +1125,8 @@ end
 -- End of module
 ----------------------------------------------------------------------
 
-setfenv(1, _G)
-M.lock(M)
-
--- Expose markdown function to the world
-markdown = M.markdown
+-- For compatibility, set markdown function as a global
+_G.markdown = markdown
 
 -- Class for parsing command-line options
 local OptionParser = {}
@@ -1183,7 +1177,7 @@ function OptionParser:run(args)
             info.f()
             pos = pos + 1
          else
-            param = args[pos+1]
+            local param = args[pos+1]
             if not param then print("No parameter for flag: " .. arg) return false end
             info.f(param)
             pos = pos+2
@@ -1197,12 +1191,12 @@ function OptionParser:run(args)
                info.f()
             else
                if i == arg:len() then
-                  param = args[pos+1]
+                  local param = args[pos+1]
                   if not param then print("No parameter for flag: -" .. c) return false end
                   info.f(param)
                   pos = pos + 1
                else
-                  param = arg:sub(i+1)
+                  local param = arg:sub(i+1)
                   info.f(param)
                end
                break