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