SentryLimit - With giant comments

Script.Load("../ns2/lua/NS2Utility.lua") //1. Allow me to show you how not to copy a bazillion lines of irrelevant NS2Utility.lua code that will likely change with every version.

//2. SourceGear DiffMerge is a wonderful program. Saw you had some modded strings in GetCrosshairText and GetSelectionText. Thought you should know if it was unintentional. I tossed em from this file to keep it simple.

//3. These could be local.
local kSentryBuildRadius = 21 //WARNING: don't set to large because it will limit sentry building on the other sides of walls.
local kMaxSentryInArea = 4

//4. Part of a neat trick for overloading CheckBuildEntityRequirements
local base_CheckBuildEntityRequirements
if not base_CheckBuildEntityRequirements then
    base_CheckBuildEntityRequirements = CheckBuildEntityRequirements //if statement is necessary so when someone saves/hotloads changes to this file that base_CheckBuildEntityRequirements doesn't grow.
end

//5. No need to recreate these strings every time that CheckBuildEntityRequirements is called
local sentryClassName = "Sentry"
local sentryErrorMessage = "Warning: Too many Sentries!"

//6. Added some "ugly" (not IMO) local variables optimizations for table.count and GetEntitiesWithinRange
local _GetEntitiesWithinRange = GetEntitiesWithinRange
local _Count = table.count

function CheckBuildEntityRequirements(techId, position, player, ignoreEntity)

    //7. Merged nested if statements. Don't worry the code won't run unless kTechId.Sentry == techId

    //8. Unnecessary/Unoptimal to use GetEntitiesForTeamWithinRange instead of GetEntitiesWithinRange.
    //   Check in decoda the implementation of GetEntitiesWithinRange and GetEntitiesForTeamWithinRange to see what i mean.
    //   Besides, aliens can't drop sentries, and if they could, i'd think you'd want this restriction to still apply.

    // Check if the entity is a Sentry
    if kTechId.Sentry == techId and _Count(_GetEntitiesWithinRange(sentryClassName, position, kSentryBuildRadius)) >= kMaxSentryInArea then
        //legalBuild, errorString
        return false, sentryErrorMessage
    end

    //call the dev's base code that was in CheckBuildEntityRequirements
    return base_CheckBuildEntityRequirements(techId, position, player, ignoreEntity)

end

//Comment regarding #7
// if you don't believe me then try this code at: http://www.lua.org/cgi-bin/demo
/*
testValue = false --try = true after you see the result with false

i = 1
function Test()
    i = i + 1
    return true
end

if testValue and Test() then
end

print(i)
*/