forked from bonsai/harakit
249 lines
6.3 KiB
Rust
249 lines
6.3 KiB
Rust
/*
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* Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* This program is free software: you can redistribute it and/or modify it under
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* the terms of the GNU Affero General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
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* details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see https://www.gnu.org/licenses/.
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*
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* This file incorporates work covered by the following copyright and permission
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* notice:
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*
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* MIT License
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*
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* Copyright (c) 2022 Lilly Cham
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files
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* (the "Software"), to deal in the Software without restriction, including
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* without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software
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* is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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* NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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use std::{
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collections::VecDeque,
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env::args,
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fmt::{ self, Display, Formatter },
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io::stdin,
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process::ExitCode,
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};
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use CalcType::*;
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extern crate sysexits;
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use sysexits::EX_DATAERR;
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#[derive(Clone, PartialEq, PartialOrd, Debug)]
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// enum CalcType is a type containing operations used in the calculator
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enum CalcType {
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Add,
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Subtract,
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Multiply,
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Divide,
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Power,
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Floor,
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Modulo,
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Val(f64),
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Invalid(String),
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}
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impl From<&str> for CalcType {
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fn from(value: &str) -> Self {
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match value {
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"+" => Add,
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"-" | "−" => Subtract,
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"*" | "×" => Multiply,
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"/" | "÷" => Divide,
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"^" | "**" => Power,
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"//" => Floor,
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"%" => Modulo,
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_ => {
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match value.parse::<f64>() {
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Ok(x) => Val(x),
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Err(_) => Invalid(value.to_owned()),
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}
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},
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}
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}
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}
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impl Display for CalcType {
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fn fmt(&self, f: &mut Formatter) -> fmt::Result {
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let y: String;
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write!(f, "{}", match self {
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Add => "addition",
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Subtract => "subtraction",
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Multiply => "multiplication",
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Divide => "division",
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Power => "exponentiation",
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Floor => "floor division",
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Modulo => "modulus",
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Val(x) => {
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y = x.to_string(); &y
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},
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Invalid(i) => {
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y = i.to_string(); &y
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},
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})
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}
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}
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#[derive(Debug, Clone)]
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struct EvaluationError {
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message: String,
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code: i32,
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}
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// I’m no math nerd but I want the highest possible approximation of 0.9
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// repeating and it seems this can give it to me
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const PRECISION_MOD: f64 = 0.9 + f64::EPSILON * 100.0;
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fn eval(
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input: &str,
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initial_stack: VecDeque<f64>,
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) -> Result<(VecDeque<f64>, bool), EvaluationError> {
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let mut stack = initial_stack;
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let mut oper = false;
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if input.is_empty() {
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stack.clear();
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return Ok((stack, oper));
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}
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// Split the input into tokens.
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let mut toks: VecDeque<CalcType> = input
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.split_whitespace()
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.rev()
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.map(|t| CalcType::from(t))
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.collect();
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let mut ops: VecDeque<CalcType> = VecDeque::new();
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while let Some(n) = toks.pop_back() {
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match n {
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Val(v) => stack.push_back(v),
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Invalid(i) => {
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return Err(EvaluationError {
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message: format!("{}: Invalid token", i),
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code: EX_DATAERR,
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})
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},
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op => {
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ops.push_back(op.clone());
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oper = true;
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let vals = (
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stack.pop_back(),
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stack.pop_back(),
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);
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if let (Some(x), Some(y)) = vals {
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match op {
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Add => stack.push_back(y + x),
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Subtract => stack.push_back(y - x),
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Multiply => stack.push_back(y * x),
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Divide => stack.push_back(y / x),
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Power => stack.push_back(x.powf(y)),
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Floor => stack.push_back((y / x).floor()),
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Modulo => stack.push_back(y % x),
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_ => {},
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};
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} else {
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return Err(EvaluationError {
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message: format!("{}: Unexpected operation.", op),
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code: EX_DATAERR,
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})
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}
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},
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};
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}
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Ok((stack, oper))
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}
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// Round a float to the given precision level
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fn round_precise(value: &f64, precision: usize) -> f64 {
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let multiplier = 10_f64.powi(precision as i32);
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(value * multiplier).round() / multiplier
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}
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fn main() -> ExitCode {
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let argv = args().collect::<Vec<String>>();
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let mut stack = VecDeque::new();
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let mut buf = String::new();
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// Set floating-point precision for correcting rounding errors based on
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// machine epsilon
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let precision = (-f64::EPSILON.log10() * PRECISION_MOD).ceil() as usize;
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if argv.get(1).is_none() {
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while let Ok(_) = stdin().read_line(&mut buf) {
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match eval(&buf.trim(), stack) {
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Ok(s) => {
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buf.clear();
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stack = s.0.clone();
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let val = match stack.iter().last() {
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Some(v) => v,
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None => break,
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};
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if s.1 == false { continue; }
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println!("{}", round_precise(val, precision).to_string());
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},
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Err(err) => {
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eprintln!("{}: {}", argv[0], err.message);
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return ExitCode::from(err.code as u8);
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},
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};
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}
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} else {
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let input = argv
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.iter()
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.skip(1)
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.map(|x| x.to_owned())
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.collect::<Vec<String>>()
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.join(" ");
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match eval(&input, stack) {
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Ok(s) => {
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stack = s.0.clone();
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let val = match stack.iter().last() {
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Some(v) => v,
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None => return ExitCode::from(0),
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};
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println!("{}", round_precise(val, precision).to_string())
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},
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Err(err) => {
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eprintln!("{}: {}", argv[0], err.message);
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return ExitCode::from(err.code as u8);
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},
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};
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}
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ExitCode::from(0)
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}
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