Zephyr currently support the following types:
i64
i32
f64
f32
bool
The four types i32, i64, f32, f64 are wasm built-in, whereas other types are built in top of them.
For now functions are the only composite type:
fun(T_1, T_2, ...) T_3
fun(T_1, T_2, ...)
// Statements
Γ |- y: T x = y
------------------
Γ |- x: T
Γ |- e: T "let" x = e
------------------------
Γ |- x: T
"if" e block_stmt
-----------------
|- e: bool
"while" e block_stmt
--------------------
|- e: bool
Γ |- f: fun(T_1, ...) T f(...) { return e }
----------------------------------------------
Γ |- e: T
// Expressions
if eq := "==" | "!="
Γ |- y: T x eq y
-------------------
Γ |- x: T
if cmp := "<" | ">" | "<=" | ">="
Γ |- y: T x cmp y
--------------------
Γ |- x: T, T ∈ {i32, i64, f32, f64}
if op != "+" | "-" | "*" | "/"
Γ |- y: T x op y
-------------------
Γ |- x: T, T ∈ {i32, i64, f32, f64}
!x
----------
|- x: bool
-x
---------------------------------
|- x: T, T ∈ {i32, i64, f32, f64}