feat(base-formula): add pretty-printer

packages/base-formula/src/format.ts

@@ -0,0 +1,32 @@
+// packages/base-formula/src/format.ts
+import type { FormulaAST, OpCode } from "./ast";
+
+const OP_STR: Partial<Record<OpCode, string>> = {
+  "+": " + ", "-": " - ", "*": " * ", "/": " / ", "%": " % ",
+  "==": " == ", "!=": " != ", ">": " > ", "<": " < ", ">=": " >= ", "<=": " <= ",
+};
+
+export function format(
+  ast: FormulaAST,
+  idToName: ReadonlyMap<string, string>,
+): string {
+  switch (ast.t) {
+    case "num":  return String(ast.v);
+    case "str":  return `"${ast.v.replace(/\\/g, "\\\\").replace(/"/g, '\\"')}"`;
+    case "bool": return ast.v ? "true" : "false";
+    case "null": return "null";
+    case "prop": return `prop("${idToName.get(ast.id) ?? ast.id}")`;
+    case "op":
+      if (ast.op === "neg") return `-${format(ast.args[0], idToName)}`;
+      if (ast.op === "not") return `not ${format(ast.args[0], idToName)}`;
+      return `(${format(ast.args[0], idToName)}${OP_STR[ast.op]}${format(ast.args[1], idToName)})`;
+    case "if":
+      return `if(${format(ast.cond, idToName)}, ${format(ast.then, idToName)}, ${format(ast.else, idToName)})`;
+    case "and":
+      return `(${ast.args.map((a) => format(a, idToName)).join(" and ")})`;
+    case "or":
+      return `(${ast.args.map((a) => format(a, idToName)).join(" or ")})`;
+    case "call":
+      return `${ast.fn}(${ast.args.map((a) => format(a, idToName)).join(", ")})`;
+  }
+}

packages/base-formula/src/index.client.ts

@@ -7,4 +7,5 @@ export * from "./tokenizer";
 export * from "./parser";
 export * from "./resolver";
 export * from "./typecheck";
+export * from "./format";
 export type { FormulaFn } from "./functions/registry";

packages/base-formula/src/index.server.ts

@@ -6,5 +6,6 @@ export * from "./tokenizer";
 export * from "./parser";
 export * from "./resolver";
 export * from "./typecheck";
+export * from "./format";
 export { registry } from "./functions/registry";
 export type { FormulaFn } from "./functions/registry";