Marey.Units 0.2.0

Marey.Units

Unit witnesses and unit rendering for Marey, a dimensionally-typed visualization system for F#.

SI base units, 22 derived units and 18 common non-SI units, each as a witness carrying its symbol, dimension, conversion factor and — where it needs one — its affine offset, together with the rendering machinery that lets an axis write its own title.

open Marey

// Canonicalisation is keyed on the dimension, not on strings. A newton composed out of base
// units and a newton stated outright are the same unit, and print the same symbol.
let composed = U.mul U.kilogram U.metrePerSecondSquared
printfn "%s" (UnitDisplay.unitText Unicode UnitRegistry.si Prefix.none composed)   // N

// Four spellings, because a LaTeX document and a terminal want different things.
printfn "%s" (UnitDisplay.unitText Siunitx UnitRegistry.si Prefix.none composed)   // \qty{}{\newton}

What it does

• Canonical symbols from physics, not from string matching. The registry is keyed on the seven-element dimension vector, so anything that composes to a newton prints N.
• Prefix selection. A domain spanning 1e-9 to 5e-9 metres yields an axis labelled nm with ticks 1, 2, 3, 4, 5. The kilogram is handled correctly — a prefix of 10⁻⁶ on float<kg> prints mg, against the gram, not µkg.
• Composed units still name themselves. U.div Derived.volt U.metre has no SI name and its dimension spells out as kg·m·s⁻³·A⁻¹. It renders V·m⁻¹, and MV·m⁻¹ when prefixed, because the witness records the factorisation it was built from. Nothing is guessed: a bare dimension is never factorised, since the same vector is both J/K and N·m/K.
• Four rendering styles — Unicode, ASCII, LaTeX and siunitx.
• Affine units. Degrees Celsius and Fahrenheit carry an offset, and IsAffine reports it. A composed unit built from an affine one drops the offset, because the quotient of an affine unit is not affine.
• Non-SI units physics actually writes in — electronvolt, angstrom, parsec, lightYear, dalton, atmosphere, bar, barn, calorie, gauss, litre, minute, hour, day, year. An electronvolt axis reads keV, not kJ.

Depends on Marey.Core and nothing else.

• The guide
• Examples