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authorNerdyPepper <[email protected]>2019-03-16 10:46:53 +0000
committerNerdyPepper <[email protected]>2019-03-16 10:46:53 +0000
commit719c5fad0249911dd4e68b96dab0969abeea515b (patch)
treec4d2aa435a7b66cb3fba3d02158b65aa80010703 /src/main.rs
parent975f606aaa0657686c5e05912977f7fb683e17e3 (diff)
use matches, enums
Diffstat (limited to 'src/main.rs')
-rw-r--r--src/main.rs112
1 files changed, 43 insertions, 69 deletions
diff --git a/src/main.rs b/src/main.rs
index 7e2057c..c9d02f7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,82 +1,56 @@
1use std::str;
2
3#[derive(Debug)] 1#[derive(Debug)]
4struct Token { 2enum Token {
5 kind: String, 3 Operator(char),
6 val: String, 4 Num(f64),
5 Paren(char)
7} 6}
8 7
9fn main() { 8fn main() {
10 let input: &str = "2y + 11(1 + 2 + 3) + 12 / 4"; 9 let input = "11(12)";
11 let input = input.replace(" ", ""); 10 let input = input.replace(" ", "");
12 println!("{}", input);
13 11
14 let mut num_vec: String = String::new(); 12 let lexed = lexer(&input);
15 let mut char_vec: String = String::new();
16 13
17 let mut result: Vec<Token> = vec![]; 14 println!("{:?}", lexed);
15}
18 16
17fn lexer(input: &str) -> Result<Vec<Token>, String> {
18 let mut num_vec: String = String::new();
19 let mut result: Vec<Token> = vec![];
19 for letter in input.chars() { 20 for letter in input.chars() {
20 if letter.is_digit(10) { 21 match letter {
21 num_vec.push(letter); 22 '0'...'9' | '.' => {
22 } else if letter == '.' { 23 num_vec.push(letter);
23 num_vec.push(letter); 24 },
24 } else if letter.is_alphabetic() { 25 '+' | '-' | '/' | '*' | '^' => {
25 drain_buffer("Literal", &num_vec[..], &mut result); 26 let parse_num = num_vec.parse::<f64>().ok();
26 char_vec.push(letter); 27 if let Some(x) = parse_num {
27 num_vec.clear(); 28 result.push(Token::Num(x));
28 } else if is_operator(letter) { 29 num_vec.clear();
29 drain_buffer("Literal", &num_vec[..], &mut result); 30 }
30 num_vec.clear(); 31 result.push(Token::Paren(letter));
31 drain_buffer("Variable", &char_vec[..], &mut result); 32 },
32 char_vec.clear(); 33 '(' => {
33 result.push(Token { kind: "Operator".into(), val: letter.to_string() }); 34 let parse_num = num_vec.parse::<f64>().ok();
34 } else if letter == '(' { 35 if let Some(x) = parse_num {
35 if char_vec.len() > 0 { 36 result.push(Token::Num(x));
36 drain_buffer("Function", &char_vec[..], &mut result); 37 result.push(Token::Operator('*'));
37 char_vec.clear(); 38 num_vec.clear();
38 } else if num_vec.len() > 0 { 39 }
39 drain_buffer("Literal", &num_vec[..], &mut result); 40 result.push(Token::Paren(letter));
40 result.push( Token{kind: "Operator".into(), val: "*".to_string()} ); 41 },
41 num_vec.clear(); 42 ')' => {
43 let parse_num = num_vec.parse::<f64>().ok();
44 if let Some(x) = parse_num {
45 result.push(Token::Num(x));
46 num_vec.clear();
47 }
48 result.push(Token::Paren(letter));
49 }
50 _ => {
51 return Err(format!("Unexpected character: {}", letter))
42 } 52 }
43 result.push( Token{kind: "Left Paren".into(), val: letter.to_string()} );
44 } else if letter == ')' {
45 drain_buffer("Literal", &num_vec[..], &mut result);
46 num_vec.clear();
47 drain_buffer("Variable", &char_vec[..], &mut result);
48 char_vec.clear();
49 result.push(Token { kind: "Right Paren".into(), val: letter.to_string() });
50 } else if letter == ',' {
51 drain_buffer("Literal", &num_vec[..], &mut result);
52 num_vec.clear();
53 drain_buffer("Variable", &char_vec[..], &mut result);
54 char_vec.clear();
55 result.push(Token { kind: "Function Arg Separator".into(), val: letter.to_string() });
56 } 53 }
57 } 54 }
58 drain_buffer("Literal", &num_vec[..], &mut result); 55 Ok(result)
59 num_vec.clear();
60 drain_buffer("Variable", &char_vec[..], &mut result);
61 char_vec.clear();
62 for token in &result {
63 println!("{} => {}", token.kind, token.val);
64 }
65}
66
67fn drain_buffer(k: &str, v: &str, result: &mut Vec<Token>) {
68 if v.len() > 0 {
69 let token = Token {
70 kind: k.into(),
71 val: v.chars().collect::<String>()
72 };
73 result.push(token);
74 }
75}
76
77fn is_operator(x: char) -> bool {
78 match x {
79 '+' | '-' | '/' | '*' | '^' => true,
80 _ => false
81 }
82} 56}