Crate hpn

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HP Voyager-inspired text-based RPN calculator

Originating from a deep desire to have an RPN calculator from inside an IRC session, the HPN struct evaluates stack-based calculator instructions in a HP Voyager-inspired “virtual calculator”.

HPN uses a 4-register stack-based RPN implementation based on and inspired by the HP Voyager series of calculators.

Calculator state and history are preserved inside the HPN object.

The current state of registers are available as instance methods; eg, hpn.x(), hpn.y(), etc.

use hpn::prelude::*;

// convert 21ºC to ºF
let mut hp = HPN::from("21 9 * 5 / 32 +");
assert_eq!(Some(69.8), hp.x().to_f64());
// or just
hp.evaluate("21 ctof");
assert_eq!(Some(69.8), hp.x().to_f64());

Snapshots of each operation performed are available via the HPN::tape() instance method.

let tape = hp.tape().collect::<Vec<_>>().join("\n");
println!("{tape}");
// Output:
// 0: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:    0.000 ]  <- 21
// 1: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:   21.000 ]  <- 9
// 2: [ T:    0.000 | Z:    0.000 | Y:   21.000 | X:    9.000 ]  <- *
// 3: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:  189.000 ]  <- 5
// 4: [ T:    0.000 | Z:    0.000 | Y:  189.000 | X:    5.000 ]  <- /
// 5: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:   37.800 ]  <- 32
// 6: [ T:    0.000 | Z:    0.000 | Y:   37.800 | X:   32.000 ]  <- +
// 7: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:   69.800 ]  <- 21
// 8: [ T:    0.000 | Z:    0.000 | Y:   69.800 | X:   21.000 ]  <- ctof
// 9: [ T:    0.000 | Z:    0.000 | Y:   69.800 | X:   69.800 ]

§Command-line Client

The easiest way to use this calculator is via the CLI client hpnc:

$ cargo install hpn
$ hpnc
hpnc x.x.x
> 77 ftoc
 0: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:    0.000 ]  <- 77
 1: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:   77.000 ]  <- ftoc
 2: [ T:    0.000 | Z:    0.000 | Y:    0.000 | X:   25.000 ]
=> 25
>

Modules§

  • Types and traits used by and with the HPN struct and associated types.

Structs§

  • Primary struct backing the HPN engine.