From 3c06cac36c695d7154623277cce82fe9fb2342b0 Mon Sep 17 00:00:00 2001
From: Chris Wanstrath <chris@ozmm.org>
Date: Wed, 29 Oct 2025 11:34:04 -0700
Subject: [PATCH] more prelude functions

---
 src/prelude/index.ts              |  83 +++++++++++++++
 src/prelude/tests/prelude.test.ts | 165 ++++++++++++++++++++++++++++++
 2 files changed, 248 insertions(+)

diff --git a/src/prelude/index.ts b/src/prelude/index.ts
index 8eb9bb3..952bca9 100644
--- a/src/prelude/index.ts
+++ b/src/prelude/index.ts
@@ -43,6 +43,27 @@ export const globalFunctions = {
     }
   },
 
+  // type predicates
+  'string?': (v: any) => toValue(v).type === 'string',
+  'number?': (v: any) => toValue(v).type === 'number',
+  'boolean?': (v: any) => toValue(v).type === 'boolean',
+  'array?': (v: any) => toValue(v).type === 'array',
+  'dict?': (v: any) => toValue(v).type === 'dict',
+  'function?': (v: any) => {
+    const t = toValue(v).type
+    return t === 'function' || t === 'native'
+  },
+  'null?': (v: any) => toValue(v).type === 'null',
+  'some?': (v: any) => toValue(v).type !== 'null',
+
+  // boolean/logic
+  not: (v: any) => !v,
+
+  // utilities
+  inc: (n: number) => n + 1,
+  dec: (n: number) => n - 1,
+  identity: (v: any) => v,
+
   // strings
   str: {
     join: (arr: string[], sep: string = ',') => arr.join(sep),
@@ -65,6 +86,10 @@ export const globalFunctions = {
     'pad-end': (str: string, length: number, pad: string = ' ') => str.padEnd(length, pad),
     lines: (str: string) => str.split('\n'),
     chars: (str: string) => str.split(''),
+    'index-of': (str: string, search: string) => str.indexOf(search),
+    'last-index-of': (str: string, search: string) => str.lastIndexOf(search),
+    match: (str: string, regex: RegExp) => str.match(regex),
+    'test?': (str: string, regex: RegExp) => regex.test(str),
   },
 
   // list
@@ -96,6 +121,18 @@ export const globalFunctions = {
     // predicates
     'empty?': (list: any[]) => list.length === 0,
     'contains?': (list: any[], item: any) => list.includes(item),
+    'any?': async (list: any[], cb: Function) => {
+      for (const value of list) {
+        if (await cb(value)) return true
+      }
+      return false
+    },
+    'all?': async (list: any[], cb: Function) => {
+      for (const value of list) {
+        if (!await cb(value)) return false
+      }
+      return true
+    },
     // sequence operations
     reverse: (list: any[]) => list.slice().reverse(),
     sort: (list: any[], cb?: (a: any, b: any) => number) => list.slice().sort(cb),
@@ -112,6 +149,34 @@ export const globalFunctions = {
     append: (list: any[], item: any) => [...list, item],
     prepend: (list: any[], item: any) => [item, ...list],
     'index-of': (list: any[], item: any) => list.indexOf(item),
+    // utilities
+    sum: (list: any[]) => list.reduce((acc, x) => acc + x, 0),
+    count: async (list: any[], cb: Function) => {
+      let count = 0
+      for (const value of list) {
+        if (await cb(value)) count++
+      }
+      return count
+    },
+    partition: async (list: any[], cb: Function) => {
+      const truthy: any[] = []
+      const falsy: any[] = []
+      for (const value of list) {
+        if (await cb(value)) truthy.push(value)
+        else falsy.push(value)
+      }
+      return [truthy, falsy]
+    },
+    compact: (list: any[]) => list.filter(x => x != null),
+    'group-by': async (list: any[], cb: Function) => {
+      const groups: Record<string, any[]> = {}
+      for (const value of list) {
+        const key = String(await cb(value))
+        if (!groups[key]) groups[key] = []
+        groups[key].push(value)
+      }
+      return groups
+    },
   },
 
   // collections
@@ -148,6 +213,21 @@ export const globalFunctions = {
     get: (dict: Record<string, any>, key: string, defaultValue: any = null) => dict[key] ?? defaultValue,
     merge: (...dicts: Record<string, any>[]) => Object.assign({}, ...dicts),
     'empty?': (dict: Record<string, any>) => Object.keys(dict).length === 0,
+    map: async (dict: Record<string, any>, cb: Function) => {
+      const result: Record<string, any> = {}
+      for (const [key, value] of Object.entries(dict)) {
+        result[key] = await cb(value, key)
+      }
+      return result
+    },
+    filter: async (dict: Record<string, any>, cb: Function) => {
+      const result: Record<string, any> = {}
+      for (const [key, value] of Object.entries(dict)) {
+        if (await cb(value, key)) result[key] = value
+      }
+      return result
+    },
+    'from-entries': (entries: [string, any][]) => Object.fromEntries(entries),
   },
 
   // math
@@ -161,6 +241,9 @@ export const globalFunctions = {
     pow: (base: number, exp: number) => Math.pow(base, exp),
     sqrt: (n: number) => Math.sqrt(n),
     random: () => Math.random(),
+    clamp: (n: number, min: number, max: number) => Math.min(Math.max(n, min), max),
+    sign: (n: number) => Math.sign(n),
+    trunc: (n: number) => Math.trunc(n),
     // predicates
     'even?': (n: number) => n % 2 === 0,
     'odd?': (n: number) => n % 2 !== 0,
diff --git a/src/prelude/tests/prelude.test.ts b/src/prelude/tests/prelude.test.ts
index 8f3d194..358dfae 100644
--- a/src/prelude/tests/prelude.test.ts
+++ b/src/prelude/tests/prelude.test.ts
@@ -87,6 +87,78 @@ describe('string operations', () => {
   test('chars splits into characters', async () => {
     await expect(`str.chars 'abc'`).toEvaluateTo(['a', 'b', 'c'], globalFunctions)
   })
+
+  test('index-of finds substring position', async () => {
+    await expect(`str.index-of 'hello world' 'world'`).toEvaluateTo(6, globalFunctions)
+    await expect(`str.index-of 'hello' 'bye'`).toEvaluateTo(-1, globalFunctions)
+  })
+
+  test('last-index-of finds last occurrence', async () => {
+    await expect(`str.last-index-of 'hello hello' 'hello'`).toEvaluateTo(6, globalFunctions)
+  })
+})
+
+describe('type predicates', () => {
+  test('string? checks for string type', async () => {
+    await expect(`string? 'hello'`).toEvaluateTo(true, globalFunctions)
+    await expect(`string? 42`).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('number? checks for number type', async () => {
+    await expect(`number? 42`).toEvaluateTo(true, globalFunctions)
+    await expect(`number? 'hello'`).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('boolean? checks for boolean type', async () => {
+    await expect(`boolean? true`).toEvaluateTo(true, globalFunctions)
+    await expect(`boolean? 42`).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('array? checks for array type', async () => {
+    await expect(`array? [1 2 3]`).toEvaluateTo(true, globalFunctions)
+    await expect(`array? 42`).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('dict? checks for dict type', async () => {
+    await expect(`dict? [a=1]`).toEvaluateTo(true, globalFunctions)
+    await expect(`dict? []`).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('null? checks for null type', async () => {
+    await expect(`null? null`).toEvaluateTo(true, globalFunctions)
+    await expect(`null? 42`).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('some? checks for non-null', async () => {
+    await expect(`some? 42`).toEvaluateTo(true, globalFunctions)
+    await expect(`some? null`).toEvaluateTo(false, globalFunctions)
+  })
+})
+
+describe('boolean logic', () => {
+  test('not negates value', async () => {
+    await expect(`not true`).toEvaluateTo(false, globalFunctions)
+    await expect(`not false`).toEvaluateTo(true, globalFunctions)
+    await expect(`not 42`).toEvaluateTo(false, globalFunctions)
+    await expect(`not null`).toEvaluateTo(true, globalFunctions)
+  })
+})
+
+describe('utilities', () => {
+  test('inc increments by 1', async () => {
+    await expect(`inc 5`).toEvaluateTo(6, globalFunctions)
+    await expect(`inc -1`).toEvaluateTo(0, globalFunctions)
+  })
+
+  test('dec decrements by 1', async () => {
+    await expect(`dec 5`).toEvaluateTo(4, globalFunctions)
+    await expect(`dec 0`).toEvaluateTo(-1, globalFunctions)
+  })
+
+  test('identity returns value as-is', async () => {
+    await expect(`identity 42`).toEvaluateTo(42, globalFunctions)
+    await expect(`identity 'hello'`).toEvaluateTo('hello', globalFunctions)
+  })
 })
 
 describe('introspection', () => {
@@ -262,6 +334,64 @@ describe('collections', () => {
     await expect(`list.index-of [1 2 3] 2`).toEvaluateTo(1, globalFunctions)
     await expect(`list.index-of [1 2 3] 5`).toEvaluateTo(-1, globalFunctions)
   })
+
+  test('list.any? checks if any element matches', async () => {
+    await expect(`
+      gt-three = do x: x > 3 end
+      list.any? [1 2 4 5] gt-three
+    `).toEvaluateTo(true, globalFunctions)
+    await expect(`
+      gt-ten = do x: x > 10 end
+      list.any? [1 2 3] gt-ten
+    `).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('list.all? checks if all elements match', async () => {
+    await expect(`
+      positive = do x: x > 0 end
+      list.all? [1 2 3] positive
+    `).toEvaluateTo(true, globalFunctions)
+    await expect(`
+      positive = do x: x > 0 end
+      list.all? [1 -2 3] positive
+    `).toEvaluateTo(false, globalFunctions)
+  })
+
+  test('list.sum adds all numbers', async () => {
+    await expect(`list.sum [1 2 3 4]`).toEvaluateTo(10, globalFunctions)
+    await expect(`list.sum []`).toEvaluateTo(0, globalFunctions)
+  })
+
+  test('list.count counts matching elements', async () => {
+    await expect(`
+      gt-two = do x: x > 2 end
+      list.count [1 2 3 4 5] gt-two
+    `).toEvaluateTo(3, globalFunctions)
+  })
+
+  test('list.partition splits array by predicate', async () => {
+    await expect(`
+      gt-two = do x: x > 2 end
+      list.partition [1 2 3 4 5] gt-two
+    `).toEvaluateTo([[3, 4, 5], [1, 2]], globalFunctions)
+  })
+
+  test('list.compact removes null values', async () => {
+    await expect(`list.compact [1 null 2 null 3]`).toEvaluateTo([1, 2, 3], globalFunctions)
+  })
+
+  test('list.group-by groups by key function', async () => {
+    await expect(`
+      get-type = do x:
+        if (string? x):
+          'str'
+        else:
+          'num'
+        end
+      end
+      list.group-by ['a' 1 'b' 2] get-type
+    `).toEvaluateTo({ str: ['a', 'b'], num: [1, 2] }, globalFunctions)
+  })
 })
 
 describe('enumerables', () => {
@@ -343,6 +473,24 @@ describe('dict operations', () => {
   test('dict.merge combines dicts', async () => {
     await expect(`dict.merge [a=1] [b=2]`).toEvaluateTo({ a: 1, b: 2 }, globalFunctions)
   })
+
+  test('dict.map transforms values', async () => {
+    await expect(`
+      double = do v k: v * 2 end
+      dict.map [a=1 b=2] double
+    `).toEvaluateTo({ a: 2, b: 4 }, globalFunctions)
+  })
+
+  test('dict.filter keeps matching entries', async () => {
+    await expect(`
+      gt-one = do v k: v > 1 end
+      dict.filter [a=1 b=2 c=3] gt-one
+    `).toEvaluateTo({ b: 2, c: 3 }, globalFunctions)
+  })
+
+  test('dict.from-entries creates dict from array', async () => {
+    await expect(`dict.from-entries [['a' 1] ['b' 2]]`).toEvaluateTo({ a: 1, b: 2 }, globalFunctions)
+  })
 })
 
 describe('math operations', () => {
@@ -405,6 +553,23 @@ describe('math operations', () => {
     await expect(`math.zero? 0`).toEvaluateTo(true, globalFunctions)
     await expect(`math.zero? 5`).toEvaluateTo(false, globalFunctions)
   })
+
+  test('math.clamp restricts value to range', async () => {
+    await expect(`math.clamp 5 0 10`).toEvaluateTo(5, globalFunctions)
+    await expect(`math.clamp -5 0 10`).toEvaluateTo(0, globalFunctions)
+    await expect(`math.clamp 15 0 10`).toEvaluateTo(10, globalFunctions)
+  })
+
+  test('math.sign returns sign of number', async () => {
+    await expect(`math.sign 5`).toEvaluateTo(1, globalFunctions)
+    await expect(`math.sign -5`).toEvaluateTo(-1, globalFunctions)
+    await expect(`math.sign 0`).toEvaluateTo(0, globalFunctions)
+  })
+
+  test('math.trunc truncates decimal', async () => {
+    await expect(`math.trunc 3.7`).toEvaluateTo(3, globalFunctions)
+    await expect(`math.trunc -3.7`).toEvaluateTo(-3, globalFunctions)
+  })
 })
 
 // describe('echo', () => {