1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
/*
eva - an easy to use calculator REPL similar to bc(1)
Copyright (C) 2019 Akshay Oppiliappan <[email protected]>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
use std::f64;
use std::env;
mod lex;
use crate::lex::*;
mod parse;
use crate::parse::*;
mod error;
use crate::error::{ CalcError, handler };
use rustyline::error::ReadlineError;
use rustyline::Editor;
use rustyline::config::{ Builder, ColorMode, EditMode };
fn main() {
let args: Vec<String> = env::args().collect();
if args.len() > 1 {
let mut expr = String::new();
for arg in args[1..].iter() {
expr.push_str(&arg[..]);
}
let evaled = eval_math_expression(&expr[..]);
match evaled {
Ok(ans) => println!("{}", 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) => println!("{}", 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 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 = autobalance_parens(&input[..])?;
let lexed = lexer(&input[..])?;
let postfixed = to_postfix(lexed)?;
let evaled = eval_postfix(postfixed)?;
Ok(format!("{:.*}", 5, evaled).parse::<f64>().unwrap())
}
#[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);
}
}
|
