✨ Support repeated option decoding

Author: cowboyd

lib/argument.ts

@@ -1,4 +1,4 @@
-import { type Param, param, type ParamModel } from "./param.ts";
+import { type AnyParam, type Param, param, type ParamModel } from "./param.ts";
 import {
   brand,
   type Check,
@@ -15,14 +15,14 @@ export function argument<
   const E extends readonly Unary[],
 >(
   named: Definition<N>,
-  ...elements: E & Check<Param<N, unknown>, E>
-): ElementOf<N, Fold<Param<N, unknown>, E>> {
+  ...elements: E & Check<Zero<N>, E>
+): ElementOf<N, Fold<Zero<N>, E>> {
   const added = elements.reduce<unknown>(
     (value, element) => element(value as never),
     param(named, positional),
-  ) as Param<string, unknown>;
+  ) as AnyParam;
 
-  return brand<ElementOf<N, Fold<Param<N, unknown>, E>>>(
+  return brand<ElementOf<N, Fold<Zero<N>, E>>>(
     (route: AnyRoute) => {
       let phases = [...route.phases];
       let phase = phases.pop()!;
@@ -51,13 +51,13 @@ export function argument<
   );
 }
 
-type ValueOf<P> = P extends Param<string, infer T> ? T : never;
+type Zero<N extends string> = Param<N, unknown, "one">;
 
-type ElementOf<N extends string, P> = P extends Param<N, unknown>
-  ? ModelElement<ParamModel<N, ValueOf<P>>>
+type ElementOf<N extends string, P> = P extends
+  Param<N, infer Model, infer _Cardinality> ? ModelElement<ParamModel<N, Model>>
   : never;
 
-function positional<P extends Param<string, unknown>>(param: P): P {
+function positional<P extends AnyParam>(param: P): P {
   return {
     ...param,
     cli: {

lib/bind.ts

@@ -1,11 +1,11 @@
-import type { Maybe } from "./maybe.ts";
-import type { Param } from "./param.ts";
+import { Just, type Maybe } from "./maybe.ts";
+import type { AnyParam, Param } from "./param.ts";
 import type { CLIRead, Symbol } from "./read.ts";
 import type { Rest } from "./rest.ts";
 import type { Result } from "./result.ts";
 import type { Word } from "./tokenize.ts";
 import type { TokenInput, Tokenizer, TokenRange } from "./tokenizer.ts";
-import type { AnyPhase, Issue, Path } from "./types.ts";
+import type { AnyPhase, Issue, OutputOf, Path } from "./types.ts";
 
 export interface Binding<T> {
   readonly rest: Rest;
@@ -24,20 +24,20 @@ export interface PhaseSegment {
   readonly path: Path;
 }
 
-export function fromCLI<const K extends string, T>(options: {
-  readonly param: Param<K, T>;
+export function fromCLI<P extends Param<string, unknown, "one">>(options: {
+  readonly param: P;
   readonly view: TokenInput<Symbol>;
   readonly rest: Rest;
-}): Maybe<Binding<T>> {
+}): Maybe<Binding<OutputOf<P["schema"]>>> {
   let { param, view, rest } = options;
   return fromRead(param, param.cli.read(view), rest);
 }
 
-export function fromValues<const K extends string, T>(options: {
-  readonly param: Param<K, T>;
+export function fromValues<P extends AnyParam>(options: {
+  readonly param: P;
   readonly route: Path;
   readonly rest: Rest;
-}): Maybe<Binding<T>> {
+}): Maybe<Binding<OutputOf<P["schema"]>>> {
   let { param, route, rest } = options;
   let claim = rest.values.claim({
     route,
@@ -60,11 +60,11 @@ export function fromValues<const K extends string, T>(options: {
   };
 }
 
-export function fromEnv<const K extends string, T>(options: {
-  readonly param: Param<K, T>;
+export function fromEnv<P extends AnyParam>(options: {
+  readonly param: P;
   readonly route: Path;
   readonly rest: Rest;
-}): Maybe<Binding<T>> {
+}): Maybe<Binding<OutputOf<P["schema"]>>> {
   let { param, route, rest } = options;
   let claim = rest.envs.claim({
     route,
@@ -78,14 +78,18 @@ export function fromEnv<const K extends string, T>(options: {
 
   let value = claim.result.value.value;
 
+  let candidates = param.cardinality === "one"
+    ? param.decode(value)
+    : param.decode([value]);
+
   return {
     exists: true,
     value: {
       rest: {
         ...rest,
         envs: claim.rest,
       },
-      result: decode(param, value, param.decode(value), [param.name]),
+      result: decode(param, value, candidates, [param.name]),
     },
   };
 }
@@ -97,12 +101,12 @@ export function bindPhase(options: {
 }): PhaseBinding {
   let { phase, segment } = options;
   let rest = options.rest;
-  let params = Object.values(phase.model.params) as Param<string, unknown>[];
+  let params = Object.values(phase.model.params) as AnyParam[];
   let pending = new Map(params.map((param) => [param.name, param]));
   let results = new Map<string, Result<unknown>>();
 
   function settle(
-    param: Param<string, unknown>,
+    param: AnyParam,
     binding: Binding<unknown>,
   ): void {
     rest = binding.rest;
@@ -111,7 +115,7 @@ export function bindPhase(options: {
   }
 
   function accept(
-    param: Param<string, unknown>,
+    param: AnyParam,
     attempt: Maybe<Binding<unknown>>,
   ): void {
     if (!attempt.exists) {
@@ -121,14 +125,16 @@ export function bindPhase(options: {
     settle(param, attempt.value);
   }
 
+  let captures = new Map<string, Capture>();
+
   // Every pending reader proposes a claim against the same immutable view.
   // Commit the proposal beginning earliest in argv, then recompute the view.
   // This lets `--port 9000` outrank a positional claim on `9000` without
   // attaching binding-policy metadata to either reader.
   while (true) {
     let horizon = first(rest.tokens, segment.range);
     let offer: {
-      param: Param<string, unknown>;
+      param: AnyParam;
       read: CLIRead;
       index: number;
     } | undefined;
@@ -154,9 +160,58 @@ export function bindPhase(options: {
       break;
     }
 
+    if (offer.param.cardinality === "many") {
+      rest = {
+        ...rest,
+        tokens: offer.read.claim.rest,
+      };
+
+      let current = captures.get(offer.param.name) ?? {
+        param: offer.param,
+        values: [],
+        issues: [],
+        failed: false,
+      };
+
+      current.issues.push(...offer.read.result.issues ?? []);
+
+      if (offer.read.result.ok && offer.read.result.value.exists) {
+        current.values.push(offer.read.result.value.value);
+      } else {
+        current.failed = true;
+      }
+      captures.set(offer.param.name, current);
+
+      continue;
+    }
+
     accept(offer.param, fromRead(offer.param, offer.read, rest));
   }
 
+  // deal wil all multiple
+  for (let capture of captures.values()) {
+    if (capture.failed) {
+      settle(capture.param, {
+        rest,
+        result: { ok: false, issues: capture.issues },
+      });
+    } else {
+      let values = capture.values;
+
+      let candidates: Maybe<unknown[]>[] = values.every(
+          (value): value is string => typeof value === "string",
+        )
+        ? capture.param.decode(values)
+        : [Just(values)];
+
+      let result = merge(
+        decode(capture.param, values, candidates, [capture.param.name]),
+        capture.issues,
+      );
+      settle(capture.param, { result, rest });
+    }
+  }
+
   // Address sources have stable visibility once the route is known. They are
   // tried only after CLI has reached its fixed point so a provisional CLI miss
   // cannot let a lower-priority source settle the parameter too early.
@@ -210,11 +265,11 @@ export function bindPhase(options: {
   return { rest, model, issues, valid };
 }
 
-function fromRead<T>(
-  param: Param<string, T>,
+function fromRead<P extends Param<string, unknown, "one">>(
+  param: P,
   read: CLIRead,
   rest: Rest,
-): Maybe<Binding<T>> {
+): Maybe<Binding<OutputOf<P["schema"]>>> {
   let path = [param.name];
 
   if (!read.result.ok) {
@@ -235,7 +290,10 @@ function fromRead<T>(
   }
 
   let value = read.result.value.value;
-  let candidates = typeof value === "string" ? param.decode(value) : [value];
+
+  let candidates = typeof value === "string"
+    ? param.decode(value)
+    : [Just(value)];
   let result = merge(
     decode(param, value, candidates, path),
     read.result.issues,
@@ -253,12 +311,12 @@ function fromRead<T>(
   };
 }
 
-function decode<T>(
-  param: Param<string, T>,
+function decode<P extends AnyParam>(
+  param: P,
   value: unknown,
-  candidates: unknown[],
+  candidates: Maybe<unknown>[],
   path: string[],
-): Result<T> {
+): Result<OutputOf<P["schema"]>> {
   if (candidates.length === 0) {
     return {
       ok: false,
@@ -271,7 +329,11 @@ function decode<T>(
 
   let issues: readonly Issue[] | undefined;
 
-  for (let candidate of candidates) {
+  let values = candidates.flatMap((candidate) =>
+    candidate.exists ? [candidate.value] : []
+  );
+
+  for (let candidate of values) {
     let result = validate(param, candidate, path);
     if (result.ok) {
       return result;
@@ -285,11 +347,11 @@ function decode<T>(
   };
 }
 
-function validate<T>(
-  param: Param<string, T>,
+function validate<P extends AnyParam>(
+  param: P,
   value: unknown,
   path: string[],
-): Result<T> {
+): Result<OutputOf<P["schema"]>> {
   let validated = param.schema["~standard"].validate(value);
   if (validated instanceof Promise) {
     return {
@@ -350,3 +412,10 @@ function earliest(tokens: readonly Symbol[]): number {
 
   return first;
 }
+
+interface Capture {
+  param: Param<string, unknown, "many">;
+  values: (string | boolean)[];
+  issues: Issue[];
+  failed: boolean;
+}

lib/decode.ts

@@ -1,26 +1,55 @@
-export type Decoder = (value: string) => unknown[];
+import { Just, type Maybe, Nothing } from "./maybe.ts";
 
-export const number: Decoder = (value) => {
+export type Decoder<A, B> = (value: A) => Maybe<B>[];
+
+export const number: Decoder<string, number> = (value) => {
   if (!numeric.test(value)) {
-    return [];
+    return [Nothing()];
   }
 
   let decoded = Number(value);
-  return Number.isFinite(decoded) ? [decoded] : [];
+  return Number.isFinite(decoded) ? [Just(decoded)] : [Nothing()];
 };
 
-export const scalar: Decoder = (value) => {
-  return [...number(value), value];
+export const scalar: Decoder<string, string | number> = (value) => {
+  return [...number(value), Just(value)];
 };
 
-export const boolean: Decoder = (value) => {
+export const boolean: Decoder<string, boolean> = (value) => {
   if (value === "true") {
-    return [true];
+    return [Just(true)];
   }
   if (value === "false") {
-    return [false];
+    return [Just(false)];
   }
-  return [];
+  return [Nothing()];
 };
 
+export function multiple<A, B>(decoder: Decoder<A, B>): Decoder<A[], B[]> {
+  return (input: A[]): Maybe<B[]>[] => {
+    let decodings = input.map(decoder);
+
+    let result: Maybe<B[]>[] = [];
+
+    for (let i = 0; i < decodings.length; i++) {
+      let decoding = decodings[i];
+      for (let j = 0; j < decoding.length; j++) {
+        let row: Maybe<B[]> | undefined = result[j];
+        if (!row) {
+          row = result[j] = Just([]);
+        }
+        if (row.exists) {
+          let candidate = decoding[j];
+          if (candidate.exists) {
+            row.value[i] = candidate.value;
+          } else {
+            result[j] = Nothing();
+          }
+        }
+      }
+    }
+    return result;
+  };
+}
+
 const numeric = /^-?\d+(?:\.\d+)?(?:[eE][+-]?\d+)?$/;

lib/env.ts

@@ -1,5 +1,5 @@
 import type { Maybe } from "./maybe.ts";
-import type { Param } from "./param.ts";
+import type { AnyParam } from "./param.ts";
 import { brand, type IdentityElement } from "./pipeline.ts";
 import type { AnyRoute, RoutePath } from "./types.ts";
 
@@ -28,9 +28,9 @@ export interface EnvClaimOptions {
 
 export function env(
   key: string,
-): IdentityElement<Param<string, unknown>> {
-  return brand<IdentityElement<Param<string, unknown>>>(
-    (param: Param<string, unknown>) => ({ ...param, env: key }),
+): IdentityElement<AnyParam> {
+  return brand<IdentityElement<AnyParam>>(
+    (param: AnyParam) => ({ ...param, env: key }),
   );
 }