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README.md
Snek Lang Parser
This is a parser implementation for snek-lang using pest.
Snek-Lang is a programming language that I'm working on and might never finish. I don't know where this will lead me.
TODO (parser)
- constructing complex type instances
- anonymous types
- pattern matching
- if-expressions
- match-expressions
- imports and exports
Snek-Lang (so far)
Primitives
100 // Int
1.0, .1 // Float
true, false // Bool
0xFF, 0b100 // Byte
"Hello World" // Str
Expressions
Every expression has to evaluate to a value
// infix addition
1 + 1
// function calls
add2 4
// nested expressions
1 * ( 1 - 1 )
// nested function calls
add2 (sub4 (mul2 4))
// if is an expression that can return a value
let value =
if a == b then
a
else
b
Declarations
A declaration declares a variable. When listing arguments in that declaration those arguments have to be provided when accessing the variable (see function call above). Declarations without variables are only evaluated once (Probably but I have to think about that).
// simple declaration
let a = 5
// add arguments (converting it into a function)
let add2 n = n + 2
// nested statements with blocks
let complex_addition a b c = {
let d = a + b
let e = b + c
d + e + 1
}
// type annotations
let a: Num = 1
// functions
let add3 a: Num -> Num = a + 3
// multi arg
let add_all a b c: Num -> Num -> Num -> Num =
a + b + c
Complex types
The value for a type is one of the following:
(|...|...)
enum{...}
record#(...)
tuple
These expressions can be nested.
type MyEnum = (
| Var1 Int
| Var2 Bool
)
type MyRec = {
field1: Float
field2: Str
}
// records declared in one line need to put a comma after each field declaration
type MyRecOneline = {field1: Float, field2: Str}
// so need tuples
type MyTuple = #(Float, Str)
type Nested = {
field1: (
| Boolean Bool
| Number Float
)
field2: #(Bool, Bool)
field3: {
first: Int
second: Int
}
}