export type Program = Array<Decl | Stmt>

// Declarations
export type Decl = VarDecl

export type VarDecl = ADecl<"var", {
    type: Type,
}>

type ADecl<Ty, Args> = {
    type: "decl",
    decl_type: Ty,
    attrs: Array<Attr>,
    name: string,
    args: Args,
}

// Statements
export type Stmt = LabelStmt | GotoStmt | AssignStmt

export type LabelStmt = AStmt<"label", {
    name: string,
}>

export type GotoStmt = AStmt<"goto", {
    name: string,
}>

export type AssignStmt = AStmt<"assign", {
    name: string,
    expr: Expr,
}>

type AStmt<Ty, Args> = {
    type: "stmt",
    stmt_type: Ty,
    args: Args,
}

// Expressions
export type Expr = BinaryExpr | UnaryExpr | BasicExpr

type BinaryExpr = {
    type: "binary",
    op: BinaryOp,
    left: Expr,
    right: Expr,
}

type UnaryExpr = {
    type: "unary",
    op: UnaryOp,
    arg: Expr,
}

type BasicExpr = number | string

type UnaryOp = "arith_negate" | "bit_negate"
type BinaryOp = "add" | "subtract" | "shift_left" | "shift_right" | "bit_and"
    | "bit_xor" | "bit_or"

// Attributes
export type Attr = {
    name: string,
    args: Array<string | number>,
}

// Types
export type Type = PrimitiveType

export type PrimitiveType = "s8" | "u8" | "u16"