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
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
use crate::tokenizer::{Token, TokenStream};
use crate::vm::{Value, Block, Op};
struct Compiler {
curr: usize,
tokens: TokenStream,
}
//TODO rustify
const PREC_NO: u64 = 0;
const PREC_ASSERT: u64 = 1;
const PREC_BOOL: u64 = 2;
const PREC_COMP: u64 = 3;
const PREC_TERM: u64 = 4;
const PREC_FACTOR: u64 = 5;
impl Compiler {
pub fn new(tokens: TokenStream) -> Self {
Self {
curr: 0,
tokens,
}
}
fn error(&self, msg: &str) -> ! {
println!("ERROR: {} range {:?}", msg, self.tokens[self.curr].1);
panic!();
}
fn peek(&self) -> Token {
if self.tokens.len() <= self.curr {
crate::tokenizer::Token::EOF
} else {
self.tokens[self.curr].0.clone()
}
}
fn eat(&mut self) -> Token {
let t = self.peek();
self.curr += 1;
t
}
fn precedence(&self, token: Token) -> u64 {
match token {
Token::Star | Token::Slash => PREC_FACTOR,
Token::Minus | Token::Plus => PREC_TERM,
Token::EqualEqual
| Token::Greater
| Token::GreaterEqual
| Token::Less
| Token::LessEqual
| Token::NotEqual
=> PREC_COMP,
Token::And | Token::Or => PREC_BOOL,
Token::AssertEqual => PREC_ASSERT,
_ => PREC_NO,
}
}
fn prefix(&mut self, token: Token, block: &mut Block) -> bool {
match token {
Token::LeftParen => self.grouping(block),
Token::Minus => self.unary(block),
Token::Float(_) => self.value(block),
Token::Int(_) => self.value(block),
Token::Bool(_) => self.value(block),
Token::Not => self.unary(block),
_ => { return false; },
}
return true;
}
fn infix(&mut self, token: Token, block: &mut Block) -> bool {
match token {
Token::Minus
| Token::Plus
| Token::Slash
| Token::Star
| Token::AssertEqual
=> self.binary(block),
Token::EqualEqual
| Token::Greater
| Token::GreaterEqual
| Token::Less
| Token::LessEqual
| Token::NotEqual
=> self.comparison(block),
_ => { return false; },
}
return true;
}
fn value(&mut self, block: &mut Block) {
let value = match self.eat() {
Token::Float(f) => { Value::Float(f) },
Token::Int(i) => { Value::Int(i) }
Token::Bool(b) => { Value::Bool(b) }
_ => { self.error("Invalid value.") }
};
block.add(Op::Constant(value));
}
fn grouping(&mut self, block: &mut Block) {
if Token::LeftParen != self.eat() {
self.error("Expected left parenthesis around expression.");
}
self.expression(block);
if Token::RightParen != self.eat() {
self.error("Expected closing parenthesis after expression.");
}
}
fn unary(&mut self, block: &mut Block) {
let op = match self.eat() {
Token::Minus => Op::Neg,
Token::Not => Op::Not,
_ => self.error("Invalid unary operator"),
};
self.value(block);
block.add(op);
}
fn binary(&mut self, block: &mut Block) {
let op = self.eat();
self.parse_precedence(block, self.precedence(op.clone()) + 1);
let op = match op {
Token::Plus => Op::Add,
Token::Minus => Op::Sub,
Token::Star => Op::Mul,
Token::Slash => Op::Div,
Token::AssertEqual => Op::AssertEqual,
_ => { self.error("Illegal operator"); }
};
block.add(op);
}
fn comparison(&mut self, block: &mut Block) {
let op = self.eat();
self.parse_precedence(block, self.precedence(op.clone()) + 1);
let op: &[Op] = match op {
Token::EqualEqual => &[Op::Equal],
Token::Less => &[Op::Less],
Token::Greater => &[Op::Greater],
Token::NotEqual => &[Op::Equal, Op::Not],
Token::LessEqual => &[Op::Greater, Op::Not],
Token::GreaterEqual => &[Op::Less, Op::Not],
_ => { self.error("Illegal comparison operator"); }
};
block.add_from(op);
}
fn expression(&mut self, block: &mut Block) {
self.parse_precedence(block, PREC_NO);
}
fn parse_precedence(&mut self, block: &mut Block, precedence: u64) {
println!("-- {:?}", self.peek());
if !self.prefix(self.peek(), block) {
self.error("Expected expression.");
}
while precedence <= self.precedence(self.peek()) {
if !self.infix(self.peek(), block) {
break;
}
}
}
pub fn compile(&mut self, name: &str) -> Block {
let mut block = Block::new(name);
loop {
if self.peek() == Token::EOF {
break;
}
self.expression(&mut block);
block.add(Op::Print);
if self.eat() != Token::Newline {
self.error("Invalid expression");
}
}
block.add(Op::Return);
block
}
}
pub fn compile(name: &str, tokens: TokenStream) -> Block {
Compiler::new(tokens).compile(name)
}
|
