parser

src/ast.ts

@@ -1,33 +1,116 @@
 import { Span } from "./error";
 
 export type ItemKind = {
-    kind: "function",
-    node: FunctionDef,
+  kind: "function";
+  node: FunctionDef;
 };
 
 export type Item = ItemKind & {
-    span: Span,
-}
+  span: Span;
+};
 
 export type FunctionDef = {
-    name: string,
-    args: FunctionArg[], 
-    body: Expr,
-}
+  name: string;
+  args: FunctionArg[];
+  body: Expr;
+};
 
 export type FunctionArg = {
-    name: string,
-    span: Span,
-}
+  name: string;
+  span: Span;
+};
 
-export type ExprKind = {
-    kind: "lit_string",
-    value: string,
-} | {
-    kind: "ident",
-    value: string,
-}
+export type ExprKind =
+  | { kind: "empty" }
+  | { kind: "let"; name: string; rhs: Expr; after: Expr }
+  | { kind: "block"; exprs: Expr[] }
+  | {
+      kind: "literal";
+      value: Literal;
+    }
+  | {
+      kind: "ident";
+      value: string;
+    }
+  | {
+      kind: "binary";
+      binaryKind: BinaryKind;
+      lhs: Expr;
+      rhs: Expr;
+    }
+  | {
+    kind: "unary",
+    unaryKind: UnaryKind,
+    rhs: Expr,
+  }
+  | {
+    kind: "call",
+    lhs: Expr,
+    args: Expr[],
+  };
 
 export type Expr = ExprKind & {
-    span: Span,
+  span: Span;
+};
+
+export type Literal =
+  | {
+      kind: "str";
+      value: string;
+    }
+  | {
+      kind: "int";
+      value: number;
+    };
+
+export type BinaryKind =
+  | "+"
+  | "-"
+  | "*"
+  | "/"
+  | "&"
+  | "|"
+  | "<"
+  | ">"
+  | "=="
+  | "<="
+  | ">="
+  | "!=";
+
+export const COMPARISON_KINDS: BinaryKind[] = [
+  ">",
+  "<",
+  "==",
+  "<=",
+  ">=",
+  "!=",
+];
+export const LOGICAL_KINDS: BinaryKind[] = ["&", "|"];
+export const ARITH_TERM_KINDS: BinaryKind[] = ["+", "-"];
+export const ARITH_FACTOR_KINDS: BinaryKind[] = ["*", "/"];
+
+const BINARY_KIND_PREC_CLASS = new Map<BinaryKind, number>([
+  ["+", 0],
+  ["-", 0],
+  ["*", 0],
+  ["/", 0],
+  ["&", 1],
+  ["|", 2],
+  ["<", 3],
+  [">", 4],
+  ["==", 5],
+  ["<=", 6],
+  [">=", 7],
+  ["!=", 8],
+]);
+
+export function binaryExprPrecedenceClass(k: BinaryKind): number {
+  const cls = BINARY_KIND_PREC_CLASS.get(k);
+  if (!cls) {
+    throw new Error(`Invalid binary kind: ${k}`);
+  }
+  return cls;
 }
+
+export type UnaryKind = '!' | '-';
+export const UNARY_KINDS: UnaryKind[] = ['!', '-'];