#moonnum

let n = @moonnum.parse_int("0xff_ec", base=0)      // 65516, any base, any size
let z = @moonnum.parse_complex("3+4j")             // (3+4j)
let f = @moonnum.parse_fraction("0.1")             // 1/10, exactly

@moonnum.repr_float(0.1 + 0.2)                     // "0.30000000000000004"
@moonnum.format(f, ".3%")                          // "10.000%"

@moonnum.repr_float(0.1)              // "0.1"     shortest string that reads back
@moonnum.float_hex(0.1)               // "0x1.999999999999ap-4"
@moonnum.as_ratio(0.1)                // 3602879701896397/36028797018963968
@moonnum.repr_float(0.1 + 0.2)        // "0.30000000000000004"
@moonnum.format(@moonnum.parse("22/7"), ".6f")   // "3.142857", exactly rounded

#Install

moon add moonbitstack/moonnum

import { "moonbitstack/moonnum" }

#The four kinds

let third = @moonnum.parse("1/3")
let total = @moonnum.parse("1") + third + @moonnum.parse("0.5")   // 11/6
let judged = @moonnum.parse("1") == @moonnum.parse("1.0")         // true

#Arithmetic

#Reading

#Writing

#The format language

[[fill]align][sign][z][#][0][width][grouping][.precision][type]

@moonnum.format_int(1234567N, "015,d")        // "000,001,234,567"
@moonnum.format_int(255N, "#010_x")           // "0x000_00ff"
@moonnum.format_float(0.25, ".2%")            // "25.00%"
@moonnum.format_float(-0.0, "z")              // "0.0"
z.format(".2f")                                // "3.00+4.00j"

#Arithmetic that can fail, fails on purpose

pub(all) suberror Refused {
  Malformed(at~ : Int, reason~ : String)   // where the text stopped making sense
  ZeroDivision
  Overflow(reason~ : String)
  Domain(reason~ : String)
}

let half = @moonnum.parse_fraction("1/2")
let bad : String = half.divide(@moonnum.parse_fraction("0")).to_string() catch {
  @moonnum.ZeroDivision => "no"
  _ => "no"
}

#What this is not

• Not a decimal type. Decimal has a context, signals and rounding modes; that is a different problem.
• Not a bignum encoding. Variable-length integer encodings live elsewhere.
• Not complex math. cmath's functions are out until something needs them.

#Documentation

• Tutorial — five pages, one per kind plus formatting. Every output block on them was produced by running the code above it, including the refusals.
• API reference — every public item.
• Design notes — how the digits are produced, and why the tower compares exactly.
• src/examples/ — moon run src/examples/01-integers and friends.

#Licence