Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

Opt-in unit catalogs via Elex.Units.Catalog and Elex.Context.put_units/2 (put_units!/2). Elex does not ship units; callers register categories, conversions, aliases, and derived formulas
Quantity results: %Elex.Quantity{value, unit: %Elex.Unit{}}. Validate returns %Elex.Dimension{} for unitful types
Literal suffixes on numeric literals: registered name or alias (10mm), power (5m^2), unbraced pipe (3 m|s), braced formula (1 {kg * m | s})
Scientific notation (1e3, 1.5E-2); e and E cannot be unit names
Conversion: evaluate(..., unit: …), validate/evaluate category: …, and expression convert/2, add_unit/2, remove_unit/1
Derived categories (formula:, hub default:, optional identity: that names the base-hub formula; a matching identity unit is still required); aliases: on add_unit; Catalog.add_unit/3 omits conversion ("value"); Catalog.kind/2
Non-additive categories (additive: false) for temperature-style points
Function units: policies (:point | :additive | :none | :convert | :wrap | :unwrap); optional call/2 and evaluate_call/2 on Elex.Function
Bang helpers: add_variable!/3, add_variables!/2, put_units!/2, Unit.new!/1, Evaluator.evaluate!/2
Ash :expected_type may be a catalog category when a catalog is attached
Helpers: Validator.same_numeric_type/2, Unit.convertible?/3, Unit.compatible?/3, Unit.from_monomial/1

Elex.extract_variables/2 requires a context so unit suffixes parse when a catalog is attached (was extract_variables/1)
Elex.add_variable/3 and Elex.add_variables/2 always return {:ok, context} | {:error, reason} (use the bang variants to pipe)
Elex.Evaluator.evaluate/2 returns {:ok, result} | {:error, reason} (use evaluate!/2 to raise; previously raised RuntimeError)
Elex.evaluate/2 no longer prefixes evaluation failures with Evaluation error:; callers receive the same reason strings as parse/validate (division by zero)
Function evaluation errors with a string reason are no longer wrapped in Error calling function name/arity: …
Without a units catalog, glued suffixes are unexpected tokens (width + 2mm → unexpected 'mm'), not a missing operand

concat is now variadic and accepts zero or more string arguments (concat() returns ""; concat("a") returns "a")

match(text, pattern) string function for regex matching
String literal escapes: \", \\, \n, \t, \r, \f, \b
Elex.Context.list_functions/1 to list registered functions with metadata (:module, :name, :arity, :signature, :description, and optional :category)
Elex.list_standard_function_modules/0 to distinguish built-in functions from custom ones
Optional :category atom in the documentation/0 callback on Elex.Function (set on all built-in functions as :math or :string)

Unknown string escape sequences now report invalid escape sequence '\X' instead of a generic missing closing quote

Unary minus operator (-x, -(1 + 2))
Modulo operator (%) with *-level precedence
null literal with equality comparisons to null and nil variables
String ordering comparisons (<, >, <=, >=) for string operands
Short-circuit evaluation for and, or, and if(condition, a, b)
Math functions: abs, pow, mod, clamp, between
Variadic min and max (two or more arguments)
String functions: concat, length, contains, starts_with, ends_with, lower, upper, trim
coalesce function (variadic; returns the first non-null argument)
Hexdocs guides: Getting Started, Expression Language, Functions, Ash Integration, and Advanced Topics

mod(a, b) now uses floored modulo (sign follows the divisor), distinct from rem(a, b) and %
between(x, low, high) returns an error when low > high, matching clamp/3

Elex.evaluate/2 returns {:error, reason} for all evaluation failures, including division by zero
Elex.Inverter.invert/2 returns {:ok, ast} or {:error, reason} instead of raising
Updated decimal dependency to ~> 3.1 and ash to ~> 3.22

Expression parsing, type validation, and evaluation with Decimal arithmetic
Arithmetic, comparison, and logical operators
Built-in functions: ceil, floor, if, max, min, pi, rem, round, sqrt
Variable substitution and variable extraction from expressions
Expression inversion for simple single-variable arithmetic
Optional Ash resource validation via Elex.AshValidation
Elex.Function behaviour for custom functions