Aegisub script to do multiple replacements a once on the sub

multiReplace.lua

--[[
multiReplace is (c) 2015 by Emmanuel Leblond <emmanuel.leblond@gmail.com>.

It is licensed to you under the terms of the WTFPLv2 (see below).

           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                   Version 2, December 2004

Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>

Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.

           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
  TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

 0. You just DO WHAT THE FUCK YOU WANT TO.

README:

Multiple Replace script, just provide the `replaces` field with something like
```
pattern1
value1

pattern2
value2
```

i.e. a pattern to search followed by it replacement, empty newlines and
patterns not followed by a replacement are ignored.
]]


-- Config, put here what you don't want to type each time
DEFAULT_REPLACES=[[
]]
DEFAULT_LIGNE_SEPARATOR='\\N'
DEFAULT_LIGNE_TARGET=1
-- DEFAULT_LINESELECT="Apply to selected lines"
DEFAULT_LINESELECT="Apply to all lines"
-- End of config, don't touch after that (unless you know what you're doing...)


-- Define some properties about the script
script_name="Multi-Replace"
script_description="Replace multiple patterns at once"
script_author="Emmanuel Leblond"
script_version="1.0"


-- No split in lua... seriously ??? O_o
function split(s, delimiter)
    result = {};
    for match in (s..delimiter):gmatch("(.-)"..delimiter) do
        table.insert(result, match);
    end
    return result;
end

buttons={"Start","Cancel"}
dialog_config={
    {
        class="dropdown",name="lineselect",
        x=0,y=0,width=1,height=1,
        items={"Apply to selected lines","Apply to all lines"},
        value=DEFAULT_LINESELECT
    },
    {
        class="label",
        x=0,y=1,width=1,height=1,
        label="\\line separator:"
    },
    {
        class="edit",name="lseparator",
        x=1,y=1,width=1,height=1,
        value=DEFAULT_LIGNE_SEPARATOR
    },
    {
        class="label",
        x=0,y=2,width=1,height=1,
        label="\\line target:"
    },
    {
        class="intedit",name="ltarget",
        x=1,y=2,width=1,height=1,
        value=DEFAULT_LIGNE_TARGET
    },
    {
        class="label",
        x=0,y=3,width=2,height=1,
        label="\\pattern=replace (one per line)"
    },
    {
        class="textbox",name="replaces",
        x=0,y=4,width=2,height=4,
        value=DEFAULT_REPLACES
    },
}


function process_line(line, separator, target, replaces)
    local splitted = {}
    if separator == '' then
        -- no separator, parse the entire line
        table.insert(splitted, line.text)
        target = 1
    else
        splitted = split(line.text, separator)
    end
    local texts = {}
    for i, sub_text in pairs(splitted) do
        if target == i then
            for _, data in ipairs(replaces) do
                pattern = data[1]
                replace = data[2]
                sub_text = sub_text:gsub(pattern, replace)
            end
        end
        table.insert(texts, sub_text)
    end
    if #texts ~= 0 then
        line.text = table.concat(texts, separator)
    end
    return line
end


function parse_replaces(raw_replaces)
    local replaces = {}
    local current_pattern = nil
    for i, raw_expr in pairs(split(raw_replaces, "\n")) do
        if raw_expr ~= nil and raw_expr ~= '' then
            -- current line contains something
            if not current_pattern then
                -- this line is the pattern to search
                current_pattern = raw_expr
            else
                -- this line is the replacement
                table.insert(replaces, {current_pattern, raw_expr})
                current_pattern = nil
            end
        else
            -- current line is just a newline, 
            current_pattern = nil
        end
    end
    return replaces
end


--This is the main processing function that modifies the subtitles
function macro_function(sub, sel, act)
    local pressed, results = aegisub.dialog.display(dialog_config,buttons)
    if pressed=="Cancel" then
        aegisub.cancel()
    end
    local replaces = parse_replaces(results['replaces'])
    local lseparator = results['lseparator']
    local ltarget = results['ltarget']
    if results['lineselect'] == "Apply to selected lines" then
        for si,li in ipairs(sel) do
            sub[li] = process_line(sub[li], lseparator, ltarget, replaces)
            aegisub.progress.set(si*100/#sel)
        end
    else
        for li=1,#sub do
            if sub[li].class == "dialogue" then
                sub[li] = process_line(sub[li], lseparator, ltarget, replaces)
                aegisub.progress.set(li*100/#sub)
            end
        end
    end
    return sel -- Preserve user selection
end

--This optional function lets you prevent the user from running the macro on bad input
function macro_validation(sub, sel, act)
    --Check if the user has selected valid lines
    --If so, return true. Otherwise, return false
    return true
end

--This is what puts your automation in Aegisub's automation list
aegisub.register_macro(script_name,script_description,macro_function,macro_validation)