Source Code Formatter

wiki

Why?

• Its a real bind doing it by hand :o)
• Inconsistency of tab sizes. Different authors and editors have different different tab sizes which may vary from the size of 8 space tabs here on the wiki. This works both ways. When you paste code here the tab size may be different and when you copy code from the wiki it may be inconsistent.
• Automatic indentation in your editor may have added tabs into your code (maybe without you even realising!). These may expand to a different size here.
• Its nice when code is a standard width so you dont have to keep resizing your viewing window.
• Homogenous appearance means more consistency for scripts which (hopefully) makes them easier on the eye. The intention being that the wiki looks like a collective effort, rather than the effort of individuals. We are the Lua Wiki Borg! :-)

Disclaimer: You are not forced to use this script!! You may experience problems when pasting code snippets or scripts into the wiki editor because of tabs. This script is here to help you. Hopefully by having a similar source code format this wiki will look consistent and more organised. Please do not start a flame war about what is good and bad formatting. You are free to do as you please.

What the script does

• Removes tab indents and replaces them with spaces.
• Standardises indentation at 2 spaces per indent.
• Checks that line lengths don't exceed 80 characters.

Usage

• Use: lua -f codeformat.lua ...options....
• --file <lua file> - the Lua file to process
• --ts <size> - the size of your tabs eg. --ts 4 (spaces)
• --in <indent size> - number of spaces you use for indentation.
• eg. lua -f codeformat.lua --file myfile.lua --ts 4 --in 4 for files with a tab size of 4 spaces and an indent step of 4 spaces.

This script works with Lua 5.0. (Thanks to whoever updated the library calls from the Lua 4.0 version.)

-- Lua code formatter
-- Removes tabs and checks lines arent too long.
-- Nick Trout
-- $Header: /Tools/build/codefmt.lua 3     16/08/01 20:00 Nick $
-- For Lua 5.0

mytabs = 4 -- spaces (default)
myindent = 4 -- spaces (default)
codetabsize = 8 -- spaces
codeindent = 2 -- spaces per indent
codelinelength = 80 -- characters


usage = 
[[

Usage: lua -f codeformat.lua ...options...

Options are:
--file <lua file>
--ts <spaces>, tabsize: number of spaces in your tabs
--in <spaces>, indent size: number of spaces for each indentation

]]


function process_args()
  -- get args set by user in command line
  local t,i = {},1
  while i<table.getn(arg) do
    local a=arg[i]
    if a=="--file" then
      t.filename,i = arg[i+1],i+2
    elseif a=="--ts" then
      t.mytabsize,i = arg[i+1]+0,i+2
    elseif a=="--in" then
      t.myindent,i = arg[i+1]+0,i+2
    else
      print(usage.."Bad flag: "..a)
      os.exit(-1)
    end
  end
  return t
end

function readfile(f)
  local fh=io.open(f,"rt")
  local t={}
  while 1 do
    local ln=fh:read("*l")
    if ln then table.insert(t,ln) else break end
  end
  fh:close()
  return t
end

-- convert any leading tabs in a given string to spaces.
-- the number of spaces to replace the tab by is given by args.mytabsize
function convertTabsToSpaces(ln)
  local s,e = string.find(ln,"\t+",1)
  if s and s==1 then
    local spc = string.rep(" ",args.mytabsize*(e-s+1))
    ln = spc..string.sub(ln,e+1)
  end
  return ln
end

-- convert any indentation to use the standard indent
function indent(ln)
  local s,e = string.find(ln," +",1)
  if s==1 then
    local indent = (e-s+1)/args.myindent
    ln = string.rep(" ",codeindent*indent)..string.sub(ln,e+1)
  end
  return ln
end
  
function process(lines)
  for li=1,table.getn(lines) do
    local line=lines[li]
    line = convertTabsToSpaces(line)
    line = indent(line)
    -- warn if length too long
    local len=string.len(line)
    if len>codelinelength then
      print("-- ######## Line too long ("..len.." chars) ######## :")
    end
    print(line)
  end
end

args = process_args()
if not args.filename then error(usage.."no Lua file given") end
args.mytabsize = args.mytabsize or mytabs
args.myindent = args.myindent or myindent
process( readfile(args.filename) )