Seven More Languages in Seven Weeks - Luaextreme-tech-seminar.github.io/7morein7/lua.pdf ·...
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. . . Lua . . . Extreme Tech Seminar . . Seven More Languages in Seven Weeks Correl Roush January 13, 2016
Transcript of Seven More Languages in Seven Weeks - Luaextreme-tech-seminar.github.io/7morein7/lua.pdf ·...
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Lua
... Extreme Tech Seminar..
Seven More Languages in Seven WeeksCorrel Roush
January 13, 2016
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...INTRODUCTION
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LUAA powerful, fast, lightweight, embeddable
scripting language
...Seven More Languages in Seven Weeks
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...DAY 1: THE CALL TO ADVENTURE
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. Installing Lua
. Exploring with the REPL. Syntax. Types. Functions
...Seven More Languages in Seven Weeks
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...SYNTAX
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Whitespace doesn’t matter
...Seven More Languages in Seven Weeks
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...TYPES
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. Lua is dynamically typed
. No integers (all numbers are 64-bit floats)
. nil is its own type
...Seven More Languages in Seven Weeks
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...FUNCTIONS
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. Functions are first-class values
. Arguments are flexible
. Support arbitrary numbers of arguments
. Support arbitrary numbers of results
. Lua does tail call optimization
...Seven More Languages in Seven Weeks
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...VARIABLES
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Lua variables are global by default
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...EXCERCISES
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Exercises...
Seven More Languages in Seven Weeks.
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...DAY 2: TABLES ALL THE WAY DOWN
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...Seven More Languages in Seven Weeks
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...TABLES AS DICTIONARIES
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book = {title = "Grail Diary",author = "Henry Jones",pages = 100
}
book.stars = 5book.author = "Henry Jones, Sr."
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...TABLES AS ARRAYS
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. Lua counts array indices starting at 1
medals = {"gold","silver","bronze"
}
medals[4] = "lead"
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...METATABLES
.function table_to_string(t)
local result = {}
for k, v in pairs(t) doresult[#result + 1] = k .. ": " .. v
end
return table.concat(result, "\n")end
greek_numbers = {ena = "one",dyo = "two",tria = "three"
}mt = {
__tostring = table_to_string}setmetatable(greek_numbers, mt)
> =greek_numbersena: onetria: threedyo: two
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...OOP
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Villain = {health = 100,new = function(self, name)
local obj = {name = name,health = self.health
}setmetatable(obj, self)self.__index = selfreturn obj
end,take_hit = function(self)
self.health = self.health - 10end
}
SuperVillain = Villain.new(Villain)
function SuperVillain.take_hit(self)-- Haha, armor!self.health = self.health - 5
end
SuperVillain:new("Toht")
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...COROUTINES
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You may be wondering how Lua handles multithreading.It doesn’t.
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...COROUTINES
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Example (Generator)function fibonacci()
local m = 1local n = 1
while true docoroutine.yield(m)m, n = n, m + n
endend
generator = coroutine.create(fibonacci)succeeded, value = coroutine.resume(generator)-- value = 1
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...MULTITASKING
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Example: Building a Scheduler
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...EXCERCISES
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Exercises...
Seven More Languages in Seven Weeks.
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...DAY 3: LUA AND THE WORLD
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Example: Making Music
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...EXCERCISES
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Exercises...
Seven More Languages in Seven Weeks.
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...WRAPPING UP
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A lot of programmers see the surface of Lua’s clean syntax and assume it’sjust another everyday scripting language. I certainly had that feeling atfirst glance. But I hope that as you’ve taken a deeper look at its tablesand coroutines, you’ve enjoyed their beauty and simplicity.
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...WRAPPING UP: STRENGTHS
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. Approachable
. Portable
. Easily included in other projects
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...WRAPPING UP: WEAKNESSES
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. Batteries not included
. Inefficient string handling
. Quirky
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...FINAL THOUGHTS
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Lua’s prototype-based object approach proves that you don’t need classesto build a great object system.
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