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/*
* eva - an easy to use calculator REPL similar to bc(1)
* Copyright (C) 2019 Akshay Oppiliappan <[email protected]>
*
*/
// std
use std::f64;
// modules
mod lex;
use crate::lex::*;
mod parse;
use crate::parse::*;
mod error;
use crate::error::{ CalcError, handler };
// extern crates
use rustyline::error::ReadlineError;
use rustyline::Editor;
use rustyline::config::{ Builder, ColorMode, EditMode };
use clap::{Arg, App};
use lazy_static::lazy_static;
struct Configuration {
radian_mode: bool,
fix: usize,
input: String
}
lazy_static! {
static ref CONFIGURATION: Configuration = parse_arguments();
}
fn main() {
if CONFIGURATION.input.len() > 0 {
let evaled = eval_math_expression(&CONFIGURATION.input[..]);
match evaled {
Ok(ans) => pprint(ans),
Err(e) => {
eprintln!("{}", handler(e));
std::process::exit(1);
},
};
} else {
let config_builder = Builder::new();
let config = config_builder.color_mode(ColorMode::Enabled)
.edit_mode(EditMode::Emacs)
.history_ignore_space(true)
.max_history_size(1000)
.build();
let mut rl = Editor::<()>::with_config(config);
if rl.load_history("history.txt").is_err() {
println!("No previous history.");
}
loop {
let readline = rl.readline("> ");
match readline {
Ok(line) => {
rl.add_history_entry(line.as_ref());
let evaled = eval_math_expression(&line[..]);
match evaled {
Ok(ans) => pprint(ans),
Err(e) => println!("{}", handler(e)),
};
},
Err(ReadlineError::Interrupted) => {
println!("CTRL-C");
break
},
Err(ReadlineError::Eof) => {
println!("CTRL-D");
break
},
Err(err) => {
println!("Error: {:?}", err);
break
}
}
}
rl.save_history("history.txt").unwrap();
}
}
fn pprint(ans: f64) {
let ans_string = format!("{:.*}", CONFIGURATION.fix, ans);
let ans_vector: Vec<&str> = ans_string.split(".").collect();
match ans_vector.len() {
1 => println!("{}", thousand_sep(ans_vector[0])),
2 => println!("{}.{}", thousand_sep(ans_vector[0]),ans_vector[1]),
_ => ()
}
}
fn thousand_sep(inp:&str) -> String {
let mut result_string = String::new();
for (i,c) in inp.to_string().chars().rev().enumerate(){
if i % 3 == 0 && i != 0 && c.to_string() != "-"{
result_string.push(',');
}
result_string.push(c)
}
let arrange = 10_usize - result_string.len() as usize;
if arrange > 0 {
result_string.push_str(" ".repeat(arrange as usize).as_str())
}
result_string.chars().rev().collect::<String>()
}
fn parse_arguments() -> Configuration {
let config = App::new(env!("CARGO_PKG_NAME"))
.version(env!("CARGO_PKG_VERSION"))
.author(env!("CARGO_PKG_AUTHORS"))
.about(env!("CARGO_PKG_DESCRIPTION"))
.arg(Arg::with_name("fix")
.short("f")
.long("fix")
.takes_value(true)
.value_name("FIX")
.help("set number of decimal places in the output"))
.arg(Arg::with_name("INPUT")
.help("optional expression string to run eva in command mode")
.index(1))
.arg(Arg::with_name("radian")
.short("r")
.long("radian")
.help("set eva to radian mode"))
.get_matches();
let mut input = String::new();
if let Some(i) = config.value_of("INPUT") {
input.push_str(i);
};
Configuration {
radian_mode: config.is_present("radian"),
fix: config.value_of("fix")
.unwrap_or("10")
.parse()
.unwrap(),
input,
}
}
fn autobalance_parens(input: &str) -> Result<String, CalcError> {
let mut balanced = String::from(input);
let mut left_parens = 0;
let mut right_parens = 0;
for letter in input.chars() {
if letter == '(' {
left_parens += 1;
} else if letter == ')' {
right_parens += 1;
}
}
if left_parens > right_parens {
let extras = ")".repeat(left_parens - right_parens);
balanced.push_str(&extras[..]);
Ok(balanced)
} else if left_parens < right_parens {
return Err(CalcError::Syntax("Mismatched parentheses!".into()))
} else {
Ok(balanced)
}
}
fn eval_math_expression(input: &str) -> Result<f64, CalcError> {
let input = input.trim();
let input = input.replace(" ", "");
if input.len() == 0 {
return Ok(0.)
}
let input = autobalance_parens(&input[..])?;
let lexed = lexer(&input[..])?;
let postfixed = to_postfix(lexed)?;
let evaled = eval_postfix(postfixed)?;
Ok(evaled)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn basic_ops() {
let evaled = eval_math_expression("6*2 + 3 + 12 -3").unwrap();
assert_eq!(24., evaled);
}
#[test]
fn trignometric_fns() {
let evaled = eval_math_expression("sin(30) + tan(45").unwrap();
assert_eq!(1.5, evaled);
}
#[test]
fn brackets() {
let evaled = eval_math_expression("(((1 + 2 + 3) ^ 2 ) - 4)").unwrap();
assert_eq!(32., evaled);
}
#[test]
fn floating_ops() {
let evaled = eval_math_expression("1.2816 + 1 + 1.2816/1.2").unwrap();
assert_eq!(3.3496, evaled);
}
#[test]
fn inverse_trignometric_fns() {
let evaled = eval_math_expression("deg(asin(1) + acos(1))").unwrap();
assert_eq!(90., evaled);
}
}
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