118 lines
3.3 KiB
Lua
118 lines
3.3 KiB
Lua
--
|
|
-- A primitive code minifier
|
|
--
|
|
-- Copyright © 2019 by luk3yx
|
|
--
|
|
|
|
-- Find multiple patterns
|
|
local function find_multiple(text, ...)
|
|
local n = select('#', ...)
|
|
local s, e, pattern
|
|
for i = 1, n do
|
|
local p = select(i, ...)
|
|
local s2, e2 = text:find(p)
|
|
if s2 and (not s or s2 < s) then
|
|
s, e, pattern = s2, e2 or s2, p
|
|
end
|
|
end
|
|
return s, e, pattern
|
|
end
|
|
|
|
-- Matches
|
|
-- These take 2-3 arguments (code, res, char) and should return code and res.
|
|
local matches = {
|
|
-- Handle multi-line strings
|
|
['%[=*%['] = function(code, res, char)
|
|
res = res .. char
|
|
char = char:sub(2, -2)
|
|
local s, e = code:find(']' .. char .. ']', nil, true)
|
|
if not s or not e then return code, res end
|
|
return code:sub(e + 1), res .. code:sub(1, e)
|
|
end,
|
|
|
|
-- Handle regular comments
|
|
['--'] = function(code, res, char)
|
|
local s, e = code:find('\n', nil, true)
|
|
if not s or not e then return '', res end
|
|
|
|
-- Don't remove copyright or license information.
|
|
if e >= 7 then
|
|
local first_word = (code:match('^[ \t]*(%w+)') or ''):lower()
|
|
if first_word == 'copyright' or first_word == 'license' then
|
|
return code:sub(s), res .. char .. code:sub(1, s - 1)
|
|
end
|
|
end
|
|
|
|
-- Shift trailing spaces back
|
|
local spaces = res:match('(%s*)$') or ''
|
|
return spaces .. code:sub(s), res:sub(1, #res - #spaces)
|
|
end,
|
|
|
|
-- Handle multi-line comments
|
|
['%-%-%[=*%['] = function(code, res, char)
|
|
char = char:sub(4, -2)
|
|
local s, e = code:find(']' .. char .. ']', nil, true)
|
|
if not s or not e then return code, res end
|
|
|
|
-- Shift trailing spaces back
|
|
local spaces = res:match('(%s*)$') or ''
|
|
return spaces .. code:sub(e + 1), res:sub(1, #res - #spaces)
|
|
end,
|
|
|
|
-- Handle quoted text
|
|
['"'] = function(code, res, char)
|
|
res = res .. char
|
|
|
|
-- Handle backslashes
|
|
repeat
|
|
local s, e, pattern = find_multiple(code, '\\', char)
|
|
if pattern == char then
|
|
res = res .. code:sub(1, e)
|
|
code = code:sub(e + 1)
|
|
elseif pattern then
|
|
res = res .. code:sub(1, e + 1)
|
|
code = code:sub(e + 2)
|
|
end
|
|
until not pattern or pattern == char
|
|
|
|
return code, res
|
|
end,
|
|
|
|
['%s*[\r\n]%s*'] = function(code, res, char)
|
|
return code, res .. '\n'
|
|
end,
|
|
|
|
['[ \t]+'] = function(code, res, char)
|
|
return code, res .. ' '
|
|
end,
|
|
}
|
|
|
|
-- Give the functions alternate names
|
|
matches["'"] = matches['"']
|
|
|
|
-- The actual transpiler
|
|
return function(code)
|
|
assert(type(code) == 'string')
|
|
|
|
local res = ''
|
|
|
|
-- Split the code by "tokens"
|
|
while true do
|
|
-- Search for special characters
|
|
local s, e, pattern = find_multiple(code, '[\'"\\]', '%-%-%[=*%[',
|
|
'%-%-', '%[=*%[', '%s*[\r\n]%s*', '[ \t]+')
|
|
if not s then break end
|
|
|
|
-- Add non-matching characters
|
|
res = res .. code:sub(1, math.max(s - 1, 0))
|
|
|
|
-- Call the correct function
|
|
local char = code:sub(s, e)
|
|
local func = matches[char] or matches[pattern]
|
|
assert(func, 'No function found for pattern!')
|
|
code, res = func(code:sub(e + 1), res, char)
|
|
end
|
|
|
|
return (res .. code):trim()
|
|
end
|