Wasp 🐝
a Lisp programming language for extremely performant and concise web assembly modules
warning: this compiler is very alpha and error messages aren't the best, but it works and language is simple!
clojure
; main.w
(extern console_log [message])
(defn main "main" []
(console_log "Hello World!"))
Features
- [x] encourages immutability
- [x] immutable c-strings, memory manipulation, global variables, imported functions, 1st class functions
- [x] optional standard library runtime
- [x] functions with inline web assembly
- [x] test framework support
- [x] easy project dependency management
- [ ] self hosting
- [ ] macros
- [ ] code pruning and inlining
- [ ] type inference
Quickstart
Wasp depends on git and rust. Make sure you have them installed before beginning.
console
cargo install wasp
wasp init myproject
cd myproject
wasp build
python3 -m http.server
Open up http://localhost:8000 and look in console. At this point we will have a web assembly module that has access to the standard libraries functions. More to come in this area!
If you don't have need for the standard library (or want to write your own!). This is also an option.
console
wasp init myproject --no-std
At this point we will have a web assembly module with a single exported main function and nothing else.
If you think your standard library is out of date, just run wasp vendor
Lisp like its 1959
Wasp is an extremely basic language and standard library. It's primary goal right
now is to be a MINIMAL Lisp that can be self hosted. Specifically:
* emphasis on recursion
* functions can be passed around as arguments
* symbols
* immutable cons data structure
clojure
(cons 42 ()) ; returns the memory location of cons
clojure
(head (cons 42 ())) ; return the head value 42
clojure
(tail (cons 42 ())) ; returns the memory location of tail
clojure
(cons 1 (cons 2 (cons 3 ()))) ; returns a linked list
Other major features that are Lispy may be added in the future.
Drawing
Using wasm-module we can easily draw something to screen. Loops in wasp work differently than other languages, bbserve how this example uses recursion to rebind variables.
```clojure
(extern globalgetWindow [])
(extern Windowgetdocument [window])
(extern DocumentquerySelector [document query])
(extern HTMLCanvasElementgetContext [element context])
(extern CanvasRenderingContext2DsetfillStyle [canvas color])
(extern CanvasRenderingContext2DfillRect [canvas x y w h])
(def colors (data "black" "grey" "red"))
(defn main "main" []
(let [window (globalgetWindow)
document (Windowgetdocument window)
canvas (DocumentquerySelector document "#screen")
ctx (HTMLCanvasElementgetContext canvas "2d")]
(loop [x 0]
(if (< x 3)
(do (CanvasRenderingContext2DsetfillStyle ctx (mem32 (+ colors (* 4 x))))
(CanvasRenderingContext2DfillRect ctx (* x 10) (* x 10) 50 50 )
(recur [x (+ x 1)]))))))
```
See it working here
Mutable Global Data
It's often important for a web assembly modules to have some sort of global data that can be changed. For instance in a game we might have a high score.
```clojure
(def high_score (data 0) )
(defn runmygame
...
(mem32 highscore (+ (mem32 highscore) 100)
...)
```
Project Management
warning: this may change but it works
Code dependencies are kept in a special folder called vendor which is populated by specific checkouts of git repositories.
For example a project.wasp containing:
bar git@github.com:richardanaya/bar.git@specific-bar
would result in these commands (roughly)
rm -rf vendor
mkdir vendor
git clone git@github.com:richardanaya/bar.git@specific-bar vendor/bar
when wasp vendor is called
Now, when wasp compiles your code, it does a few things.
- In order specified by your
project.wasp, one folder at a time all files ending in .w are loaded from each vendor/<dependency-name> and its subfolders.
- all files in the current directory and sub directories not in
vendor are loaded
- then everything is compiled in order
Please try to use non conflicting names in meantime while this is fleshed out for 0.2.0
Advanced
When necessary, low level web assembly can be directly inlined
```clojure
(defn-wasm memswap [i32] [i32] ; 1 input, 1 output
[i32] ; int tmp = 0;
; tmp = a
LOCALGET 0
LOCALSET 2
; a = b
LOCALGET 1
LOCALSET 0
; b = tmp
LOCALGET 2
LOCALSET 1
END )
(defn main "main" []
...
(memswap 10, 20) )
```
Technical Details
Types
- integer - a 32-bit integer (e.g
-1, 0, 42)
- string - a 32-bit pointer to a location in memory of the start of of a c-string (e.g.
"hello world!")
- symbol - a 32-bit pointer to a location in memory of the start of of a c-string (e.g.
":hello_world")
- bool - a 32-bit number representing boolean values. True is 1, false is 0. (e.g.
true false)
- empty - a 32-bit pointer to an empty value (e.g.
())
- data - a global only type this is a a 32-bit pointer to sequence of 32-bit values in memory (e.g.
(data 1 true :hey (data :more-data ())). Use this for embedding raw data into your application memory on startup.
Functions
- (defn name "export-name" ... ) - create a function that executes a list of expressions returning the result of the last one. Optionally provide an export name to make visible to host.
- (function-name ...) - call a function with arguments
- (mem x:integer) - get 8-bit value from memory location x
- (mem x:integer y) - set 8-bit value at memory location x to value y
- (mem32 x:integer) - get 32-bit value from memory location x
- (mem32 x:integer y) - set 32-bit value at memory location x to value y
- (if x y) - if x is true return expression y otherwise return empty
- (if x y z) - if x is true return expression y otherwise return expression z
- (do ... ) - executes a list of expressions and returns the value of the last. useful putting complicated expressions in places that expect one expression.
- (let [x0:identifier y0:expression x1:identifier y1:expression ... ] ... ) - bind pairs of values to identifiers. Then run a sequence of expressions that can use those values by their identifier. Returns the value of the last expression in sequence. bindings specified in let shadow those at higher scopes.
- (loop [x0:identifier y0:expression x1:identifier y1:expression ... ] ... x ) - bind pairs of values to identifiers. Then run a sequence of expressions that can use those values by their identifier. Returns the value of the last expression in sequence. bindings specified in loop shadow those at higher scopes.
- (recur [x0:identifier y0:expression x1:identifier y1:expression ... ] ... x ) - rebinds pairs of values to identifiers and restarts the innermost loop.
- (fnsig [x0 x1 .. ] y) - gets the value of a function signature with inputs x0, x1, etc and output y
- **(call x f y0 y1 ...) call a function with signature x and function handle f with parameters y0, y1, ...
- (+ ...) - sums a list of values and returns result
- (- ...) - subtracts a list of values and returns result
- (* ...) - multiplies a list of values and returns result
- (/ ...) - divides a list of values and returns result
- (% ...) - modulos a list of values and returns result
- (== x y) - returns true if values are equal, false if otherwise
- (!= x ) - returns true if values are not equal, false if otherwise
- (empty? x ) - returns true if value x is empty (), false if otherwise
- (< x y) - returns true if x is less than y, false if otherwise
- (> x y) - returns true if x is greater than y, false if otherwise
- (<= x y) - returns true if x is less than or equal y, false if otherwise
- (>= x y) - returns true if x is greater than or equal y, false if otherwise
- (&& x y) - returns true if x and y are greater than zero, false if otherwise
- (|| x y) - returns true if x or y are greater than zero, false if otherwise
- (& x y) - returns bitwise and of x and y
- (| x y) - returns bitwise or of x and y
- (! x ) - returns true if zero and false if not zero
- (^ x ) - bitwise exclusive or of x
- (~ x ) - bitwise complement of x
- (<< x y) - shift x left by y bits
- (>> x y) - shift x right by y bits
Testing
- (deftest x0 x1) - executes expression x0 then x1 etc. and stops when it first encounters a non empty value and return the value otherwise returns empty. Test names will be exported by default as
"test_"+name when compiled with wasp build --testing.
- (is x y) - if condition x is true returns () otherwise returns c-string y
clojure
(deftest addition
(is (= 4 (+ 2 2)) "2 + 2 should be 4")
(is (= 7 (+ 3 4)) "3 + 4 should be 7"))
See it working here
Why so few functions?
Wasp prefers to keep as little in the core functionality as possible, letting the standard library evolve faster and more independent community driven manner. This project currently follows a principle that if a feature can be implemented with our primitive functions, don't include it in the core compiled language and let the standard library implement it. Also that no heap based concepts be added to the core language.
Notes
- all functions (including extern functions) return a value, if no obvious return, it is an empty value
()
- Web assembly global 0 is initialized to the end of the static data section (which might also be the start of a heap for a memory allocator). This value is immutable.
- Web assembly global lobal 1 also is initialized to the end of the static data section. This value is mutable and might be used to represent the end of your heap. Check out the simple allocator example.
- Literal strings create initialize data of a c-string at the front of your memory, and can be passed around as pointers to the very start in memory to your text. A 0 is automatically added at compile time, letting you easily have a marker to denote the end of your text.