Arduino programming of ML-style in ATS

Arduino programming of ML-
style in ATS
style in ATS
style in ATS
style in ATS
style in ATS
Kiwamu Okabe @ METASEPI
DESIGN / Hongwei Xi @ Boston
University
University
University
University
University

Demo: VideoDemo: VideoDemo: VideoDemo: VideoDemo: Video
☆ LCD greeting☆ LCD greeting☆ LCD greeting☆ LCD greeting☆ LCD greeting
☆ ⇒ http://youtu.be/5uPue0Jo1nc☆ ⇒ http://youtu.be/5uPue0Jo1nc☆ ⇒ http://youtu.be/5uPue0Jo1nc☆ ⇒ http://youtu.be/5uPue0Jo1nc☆ ⇒ http://youtu.be/5uPue0Jo1nc
☆ LED fadein☆ LED fadein☆ LED fadein☆ LED fadein☆ LED fadein
☆ ⇒ http://youtu.be/_Sx6GzuTm9k☆ ⇒ http://youtu.be/_Sx6GzuTm9k☆ ⇒ http://youtu.be/_Sx6GzuTm9k☆ ⇒ http://youtu.be/_Sx6GzuTm9k☆ ⇒ http://youtu.be/_Sx6GzuTm9k

Demo: Software ArchitectureDemo: Software ArchitectureDemo: Software ArchitectureDemo: Software ArchitectureDemo: Software Architecture

Arduino Uno hardwareArduino Uno hardwareArduino Uno hardwareArduino Uno hardwareArduino Uno hardware
It's poor.It's poor.It's poor.It's poor.It's poor.
☆ 8-bit Harvard architecture☆ 8-bit Harvard architecture☆ 8-bit Harvard architecture☆ 8-bit Harvard architecture☆ 8-bit Harvard architecture
☆ Flash Memory: 32 KB☆ Flash Memory: 32 KB☆ Flash Memory: 32 KB☆ Flash Memory: 32 KB☆ Flash Memory: 32 KB
☆ SRAM: 2 KB☆ SRAM: 2 KB☆ SRAM: 2 KB☆ SRAM: 2 KB☆ SRAM: 2 KB
Many people use C language on the
hardware.
hardware.
hardware.
hardware.
hardware.

Problem of C languageProblem of C languageProblem of C languageProblem of C languageProblem of C language
☆ Memory/Resource leak☆ Memory/Resource leak☆ Memory/Resource leak☆ Memory/Resource leak☆ Memory/Resource leak
☆ Out of bounds☆ Out of bounds☆ Out of bounds☆ Out of bounds☆ Out of bounds
☆ Weak type☆ Weak type☆ Weak type☆ Weak type☆ Weak type
We need functional language for
embedded system!
embedded system!
embedded system!
embedded system!
embedded system!

Approach 1: Virtual machineApproach 1: Virtual machineApproach 1: Virtual machineApproach 1: Virtual machineApproach 1: Virtual machine

Approach 2: DSLApproach 2: DSLApproach 2: DSLApproach 2: DSLApproach 2: DSL

Approach 3: Direct languageApproach 3: Direct languageApproach 3: Direct languageApproach 3: Direct languageApproach 3: Direct language

Comparison of the approachesComparison of the approachesComparison of the approachesComparison of the approachesComparison of the approaches
We choose the 3rd approach.We choose the 3rd approach.We choose the 3rd approach.We choose the 3rd approach.We choose the 3rd approach.

ATS languageATS languageATS languageATS languageATS language
☆ http://www.ats-lang.org/☆ http://www.ats-lang.org/☆ http://www.ats-lang.org/☆ http://www.ats-lang.org/☆ http://www.ats-lang.org/
☆ DML-style dependent types☆ DML-style dependent types☆ DML-style dependent types☆ DML-style dependent types☆ DML-style dependent types
☆ Linear types☆ Linear types☆ Linear types☆ Linear types☆ Linear types
☆ Optional GC☆ Optional GC☆ Optional GC☆ Optional GC☆ Optional GC
☆ Optional malloc/free☆ Optional malloc/free☆ Optional malloc/free☆ Optional malloc/free☆ Optional malloc/free
☆ Optional run-time☆ Optional run-time☆ Optional run-time☆ Optional run-time☆ Optional run-time

Author: Hongwei XiAuthor: Hongwei XiAuthor: Hongwei XiAuthor: Hongwei XiAuthor: Hongwei Xi

ATS programming levelATS programming levelATS programming levelATS programming levelATS programming level
Today, we focus on the level "c",
because Arduino hardware is poor.

Functional style programmingFunctional style programmingFunctional style programmingFunctional style programmingFunctional style programming
☆ Functional style programming can be
used with ATS on embedded system?
☆ Yes.☆ Yes.☆ Yes.☆ Yes.☆ Yes.
☆ But only use some of functional style
technique in ATS without GC and
malloc/free.
malloc/free.
malloc/free.
malloc/free.
malloc/free.
☆ Let's see some examples.☆ Let's see some examples.☆ Let's see some examples.☆ Let's see some examples.☆ Let's see some examples.

Style 1. Envless functionStyle 1. Envless functionStyle 1. Envless functionStyle 1. Envless functionStyle 1. Envless function
☆ Environment-less function.☆ Environment-less function.☆ Environment-less function.☆ Environment-less function.☆ Environment-less function.
☆ Not closure.☆ Not closure.☆ Not closure.☆ Not closure.☆ Not closure.
☆ C language function is also envless
function.
function.
function.
function.
function.
%{^ // C language code
int cfunc(int a, int b) {
return (a + b);
}
%}
// ATS language code
extern fun cfunc (a: int, b: int): int = "mac#"
implement main0 () = println! (cfunc (1, 2)) // => 3
return (a + b);
}
%}
return (a + b);
}
%}
return (a + b);
}
%}
return (a + b);
}
%}

Style 2. Stack allocated closureStyle 2. Stack allocated closureStyle 2. Stack allocated closureStyle 2. Stack allocated closureStyle 2. Stack allocated closure
Stack allocated closure is allocated on
stack. It can use free variable.
fun run (f: &int -<clo1> int): int = f 1
implement main0 () = {
val b = 2
var plus = lam@ (a: int):int => a + b
val () = println! (run plus) // => 3
}
val b = 2
}
val b = 2
}
val b = 2
}
val b = 2
}

Style 3. Template functionStyle 3. Template functionStyle 3. Template functionStyle 3. Template functionStyle 3. Template function
The template is functorial style that has
lexical scoping.
lexical scoping.
lexical scoping.
lexical scoping.
lexical scoping.
extern fun{} base (): int
fun{} plus (a: int): int = a + base ()
implement{} base () = 2
val () = println! (plus 1) // => 3
}
}
}
}
}

Safety shaped by ATSSafety shaped by ATSSafety shaped by ATSSafety shaped by ATSSafety shaped by ATS
☆ ATS is a better C language.☆ ATS is a better C language.☆ ATS is a better C language.☆ ATS is a better C language.☆ ATS is a better C language.
☆ "Better" is meaning "Safer".☆ "Better" is meaning "Safer".☆ "Better" is meaning "Safer".☆ "Better" is meaning "Safer".☆ "Better" is meaning "Safer".
☆ Let's see some examples.☆ Let's see some examples.☆ Let's see some examples.☆ Let's see some examples.☆ Let's see some examples.

Safety 1. Termination metricsSafety 1. Termination metricsSafety 1. Termination metricsSafety 1. Termination metricsSafety 1. Termination metrics
".<255 - n>." is termination metric that
grows smaller on each recursive call,
for termination-checking.
fun loop_fadein {n:nat | n <= 255} .<255 - n>. (i: int n): void = {
val () = analogWrite (LED, i)
val () = delay_ms (BLINK_DELAY_MS)
val () = if i < 255 then loop_fadein (i + 1)
}
...
val () = loop_fadein 0
}
...
}
...
}
...
}
...

Safety 2. DML dependent typesSafety 2. DML dependent typesSafety 2. DML dependent typesSafety 2. DML dependent typesSafety 2. DML dependent types
"size_t (i)" is a type that depends on
static value "i". "i" has constraint "i < n".
If the constraint is not solved, it causes
compile error.
compile error.
compile error.
compile error.
compile error.
fun lcd_print {n:int}{i:nat | i < n}{j:nat | i + j <= n}
(lcd: !lcd_t, str: string (n), start: size_t (i),
len: size_t (j)): void

Safety 3. ViewSafety 3. ViewSafety 3. ViewSafety 3. ViewSafety 3. View
Linear proofs should be produced and
consumed.
consumed.
consumed.
consumed.
consumed.
If a produced linear proof is not
consumed, it causes type error at
compile time.
compile time.
compile time.
compile time.
compile time.
// lcd.sats - Library interface
absvtype lcd_t = ptr
fun lcd_open (rs: int, rw: int, enable: int, d0: int, d1: int,
d2: int, d3: int): lcd_t // Produce linear value
fun lcd_close (lcd: lcd_t): void // Consume linear value
// main.dats - Application code
implement main () = {
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
// ...Do something...
val () = lcd_close lcd // <= If not, compile error occurs.
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}

Safety 4. At-viewSafety 4. At-viewSafety 4. At-viewSafety 4. At-viewSafety 4. At-view
dataview array_v (a:t@ype+, addr, int) =
| {l:addr} array_v_nil (a, l, 0)
| {l:addr}{n:nat} array_v_cons (a, l, n+1) of
(a @ l, array_v (a, l+sizeof(a), n))

Demo code: LED fadeinDemo code: LED fadeinDemo code: LED fadeinDemo code: LED fadeinDemo code: LED fadein
#define LED 9
#define DELAY_MS 10.0
typedef analog_w_t = natLt(256)
fun{} int_foreach_clo{n:nat}
(n: int(n), fwork: &natLt(n) -<clo1> void): void =
loop(0, fwork) where {
fun loop{i:nat | i <= n} .<n-i>.
(i: int(i), fwork: &natLt(n) -<clo1> void): void =
if i < n then (fwork(i); loop (i+1, fwork))
}
fun fadein() = let
var fwork = lam@ (n: analog_w_t) =>
(analogWrite (LED, n); delay_ms(DELAY_MS))
in
int_foreach_clo(256, fwork)
end // end of [fadein]
val () = pinMode (LED, OUTPUT)
val () = (fix f(): void => (fadein(); f()))()
}
#define LED 9
}
fun fadein() = let
in
}
#define LED 9
}
fun fadein() = let
in
}
#define LED 9
}
fun fadein() = let
in
}
#define LED 9
}
fun fadein() = let
in
}

Demo code: LCD greeting (cont.)Demo code: LCD greeting (cont.)Demo code: LCD greeting (cont.)Demo code: LCD greeting (cont.)Demo code: LCD greeting (cont.)
#define MY_DELAY_MS 400.0
#define LCD_WIDTH 16
val g_str_atsrun = "<ATS running!>"
val g_str_message = "...Greeting message..."
fun loop {n:int}{i:nat | i < n} .<n-i>.
(lcd: !lcd_t, str: string (n), pos: size_t (i)): void = {
val () = if pos + i2sz LCD_WIDTH <= length str then {
val () = lcd_setCursor (lcd, 1, 0)
val () = lcd_print (lcd, g_str_atsrun, i2sz 0,
length g_str_atsrun)
val () = lcd_print (lcd, str, pos, i2sz LCD_WIDTH)
val () = delay_ms (MY_DELAY_MS)
val () = loop (lcd, str, pos + 1)
}
}
}
}
}
}
}
}
}
}

Demo code: LCD greetingDemo code: LCD greetingDemo code: LCD greetingDemo code: LCD greetingDemo code: LCD greeting
fun forever {n:int}{i:nat | i < n}
(lcd: !lcd_t, str: string (n), pos: size_t (i)):
void = {
val () = loop (lcd, str, pos)
val () = forever (lcd, str, pos)
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
val () = forever (lcd, g_str_message, i2sz 0)
val () = lcd_close lcd
}
void = {
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}
void = {
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}
void = {
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}
void = {
}
val lcd = lcd_open (8, 13, 9, 4, 5, 6, 7)
}

Binary size efficiencyBinary size efficiencyBinary size efficiencyBinary size efficiencyBinary size efficiency
For examples on "Getting Started with
Arduino", ATS has good binary size
efficiency as well as C.

ConclusionConclusionConclusionConclusionConclusion
☆ Can we directly use functional style
programming on embedded system?
☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.
☆ Can we make more safety than C
language on embedded system?
☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.☆ ⇒ Yes, with ATS language.
https://github.com/fpiot/arduino-atshttps://github.com/fpiot/arduino-atshttps://github.com/fpiot/arduino-atshttps://github.com/fpiot/arduino-atshttps://github.com/fpiot/arduino-ats

License of photos #1License of photos #1License of photos #1License of photos #1License of photos #1
* Minecraft toys | Flickr - Photo Sharing!
https://www.flickr.com/photos/sergesegal/15976451410/
Copyright: 2015 Sergey Galyonkin / License: CC BY-SA 2.0
* Arduino Uno | Flickr - Photo Sharing!
https://www.flickr.com/photos/snootlab/6052455554/
Copyright: Snootlab / License: CC BY 2.0
* Thank You Dennis Ritchie | Flickr - Photo Sharing!
https://www.flickr.com/photos/vincentpants/6239875256/
Copyright: Vincent van Haaff / License: CC BY-SA 2.0
* Climbing Journal Mount Rinjani package | Flickr - Photo Sharing!
https://www.flickr.com/photos/trekkingrinjani/4930552641/
Copyright: Trekking Rinjani / License: CC BY 2.0
* Recycling Grunge Sign | Flickr - Photo Sharing!
https://www.flickr.com/photos/80497449@N04/8677649972/
Copyright: Nicolas Raymond / License: CC BY 2.0
* IMG_4097 | Flickr - Photo Sharing!
https://www.flickr.com/photos/matthewpiatt/1562708158/
Copyright: Matthew Piatt / License: CC BY-SA 2.0
* Seagulls in Flight | Flickr - Photo Sharing!
Copyright: Shaun Fisher / License: CC BY 2.0

License of photos #2License of photos #2License of photos #2License of photos #2License of photos #2
* Arduino Uno unboxing | Flickr - Photo Sharing!
https://www.flickr.com/photos/mightyohm/5052594028/
Copyright: Jeff Keyzer / License: CC BY-SA 2.0
* Creative Commons BBB | Flickr - Photo Sharing!
https://www.flickr.com/photos/steren/2732488224/
Copyright: Steren Giannini / License: CC BY 2.0
* LED | Flickr - Photo Sharing!
https://www.flickr.com/photos/nao904/6084536885/
Copyright: Nao. Fujita / License: CC BY 2.0
* Pagoda's curly steps | Flickr - Photo Sharing!
https://www.flickr.com/photos/kewl/6834141860/
Copyright: Tristan Schmurr / License: CC BY 2.0

Arduino programming of ML-style in ATS

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