XPR Language

Appearance

Changelog ​

All notable changes to the XPR language specification and runtimes.

v0.5.0 ​

Math

  • New functions: sqrt(n), log(n), pow(x, y), random(), sign(n), trunc(n)
  • New constants: PI, E

Type Predicates

  • isNumber(v), isString(v), isArray(v), isNull(v), isObject(v), isRegex(v)

Array Methods

  • sortBy(fn), take(n), drop(n), count(fn), sum(), avg(), compact()
  • partition(fn), keyBy(fn), min(), max(), first(), last()

Other

  • fromEntries(pairs) — inverse of .entries()
  • str.split(/regex/) — regex overload for string split
  • Rest parameters in arrow functions: (...args) => expr, (a, ...rest) => expr

v0.4.0 ​

Destructuring

  • Object destructuring in let bindings: let {name, age} = user; name
  • Array destructuring in let bindings: let [first, ...rest] = items; rest
  • Destructuring in arrow function parameters: users.map(({name}) => name)
  • Defaults, renaming, nested, and rest patterns supported

Regex

  • Regex literals: /pattern/flags — first-class regex type (7th type)
  • Regex methods: /re/.test(str), str.match(/re/), str.replace(/re/, str)
  • Supported flags: i, m, s

v0.3.0 ​

Date/Time (epoch milliseconds, UTC only)

  • now(), parseDate(str, format?), formatDate(date, format)
  • year(d), month(d), day(d), hour(d), minute(d), second(d), millisecond(d)
  • dateAdd(date, amount, unit), dateDiff(date1, date2, unit)

Regex Functions

  • matches(str, pattern), match(str, pattern), matchAll(str, pattern), replacePattern(str, pattern, repl)
  • RE2 flavor. Inline flags via (?i) etc.

Other

  • Negative array indexing: items[-1] returns last element
  • Spread in function call arguments: fn(...args), fn(a, ...rest)

v0.2.0 ​

Let Bindings

  • Immutable scoped bindings: let x = 1; x + 1
  • Chained: let x = 1; let y = x + 1; y
  • Arrow functions as values: let f = (x) => x * 2; f(5)

Spread Operator

  • Array spread: [...arr1, ...arr2]
  • Object spread: {...obj1, ...obj2}

New Array Methods

  • includes, indexOf, slice, join, concat, flat, unique, zip, chunk, groupBy

New String Methods

  • indexOf, repeat, trimStart, trimEnd, charAt, padStart, padEnd

New Object Methods

  • entries(), has(key)

New Global

  • range(end), range(start, end), range(start, end, step)

v0.1.0 ​

Core

  • Literals: numbers, strings, booleans, null, arrays, objects, template literals
  • Arithmetic: +, -, *, /, %, **
  • Comparison: ==, !=, <, >, <=, >=
  • Logic: &&, ||, !, ternary a ? b : c, nullish coalescing ??

Access

  • Dot and bracket notation: user.name, user["name"], items[0]
  • Optional chaining: user?.address?.city

Collections

  • Arrow functions: x => x * 2, (x, y) => x + y
  • Methods: map, filter, reduce, find, some, every, flatMap, sort, reverse
  • Property: .length

Strings

  • Methods: len, upper, lower, trim, startsWith, endsWith, contains, split, replace, slice

Math

  • round, floor, ceil, abs, min, max

Type

  • type(v), int(v), float(v), string(v), bool(v)

Object

  • keys(), values()

Pipe

  • |> operator: data |> filter(x => x.active) |> map(x => x.name)

Runtimes

  • JavaScript/TypeScript: @xpr-lang/xpr
  • Python: xpr-lang
  • Go: github.com/xpr-lang/xpr-go