Scalars & Strings

Nomi has three numeric scalar types — Int, Float, Decimal — plus Bool and String. Each operator on this page works exactly as you’d guess from other languages; this chapter’s job is to show the syntax, point out where Nomi differs (mostly: Decimal), and move on.

Numbers, booleans, operators

Arithmetic, comparisons, and the logical operators and / or / ! all read as you’d expect:

fn main(): Bool {
  dbg 42 + 8
  dbg 10 - 3
  dbg 2 * 21
  dbg 20 / 4
  dbg -(3 + 4)
  dbg 42 > 10
  dbg True and !False
}

Number literal forms

Numbers can use digit separators, alternate radices (hex / binary / octal), or scientific notation — different spellings of the same values:

fn main(): Float {
  dbg 1_000_000
  dbg 0xFF
  dbg 0b1010
  dbg 1.0e10
}

Decimal — exact arithmetic

Float is fast but approximate: small rounding errors accumulate, and familiar identities like the one below quietly fail. Decimal is the exact alternative — use it whenever rounding error is a bug (money, billing, anywhere correctness matters more than speed). Decimal literals carry a d suffix:

fn main(): Decimal {
  // Float carries base-2 imprecision
  dbg 0.1 + 0.2 == 0.3

  // Decimal is exact
  dbg 0.1d + 0.2d == 0.3d

  // Sum four prices to the cent — exactly
  dbg 19.99d + 5.00d + 2.50d + 0.99d
}

Strings — interpolation and concatenation

Strings interpolate ${expr} and concatenate with +:

import std/io: IO

fn main() {
  name = "Nomi"
  IO.print("Hello, ${name}!")
  IO.print("1 + 2 = ${1 + 2}")
  IO.print("Hello" + ", " + "Nomi")
}

IO.print accepts any value that can be displayed, so you rarely need to stringify before printing — interpolation calls each value’s Display.to_string for you.

+, -, *, and / are backed by standard operator interfaces. The built-in scalar impls cover numeric arithmetic; + also covers string concatenation. Custom types can implement the same interfaces when the operator is the clearest domain operation.

Triple-quoted strings

A """…""" literal spans multiple lines. Interpolation works the same way, and leading indentation common to every line is stripped:

import std/io: IO

fn main() {
  name = "Alice"
  query = """
    SELECT *
    FROM users
    WHERE name = '${name}'
    """
  IO.print(query)
}

The next chapter — Collections — uses these scalar values inside lists, maps, and sets.