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
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
//! # BrainFuck compiler using Rust proc macro
//! More precisely, the BrainFuck-to-Rust transpiler using Rust proc macro
//! 
//! ## Examples:
//! 
//! 1. Hello World
//!    (run on dropping)
//!    ```rust
//!    brain_fuck!(
//!        ++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.
//!        >---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.
//!    );
//!    ```
//! 2. using `into` method to obtain `(pc: usize, mem: Vec<u8>)` after running
//!    (run on `into` calling)
//!    ```rust
//!    let (pc, mem) = brain_fuck!(
//!        ++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[
//!            -<<<[
//!                ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
//!            ]>.>+[>>]>+
//!        ]
//!    ).into();
//!    println!("{:?}", (pc, mem));
//!    ```
//! 3. use `env` method to set _Program Counter_ `pc` and _Memory_ `mem` for brainfuck codeblock
//!    (run on dropping)
//!    ```rust
//!    brain_fuck!(
//!        [.>]
//!    ).env(0, vec![79, 75, 10]);
//!    ```
//! 4. Altogether
//!    (run on `into` calling)
//!    ```rust
//!    let (pc, mem) = brain_fuck!(
//!        ++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.
//!        >---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.
//!    ).env(0, vec![]).into();
//!    println!("{:?}", (pc, mem));
//!    ```
//! 
//! 
//! 
//! ## Explaination
//! The brainfuck code
//! ```brainfuck
//! brainfuck!(
//!     ++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[
//!         -<<<[
//!             ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
//!         ]>.>+[>>]>+
//!     ]
//! )
//! ```
//! will be transpiled to the following rust code
//! ```rust
//! ::bflib::BrainfuckBlock::new(&|pc: &mut usize, mem: &mut Vec<u8>| {
//!     if mem.len() <= *pc {
//!         mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!     }
//!     mem[*pc] = mem[*pc].wrapping_add(8);
//!     while mem[*pc] != 0 {
//!         *pc += 1;
//!         if mem.len() <= *pc {
//!             mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!         }
//!         mem[*pc] = mem[*pc].wrapping_add(1);
//!         *pc += 1;
//!         if mem.len() <= *pc {
//!             mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!         }
//!         mem[*pc] = mem[*pc].wrapping_add(4);
//!         if *pc < 2 {
//!             panic!("BrainFuck Program Counter reduced to below zero !!!");
//!         } else {
//!             *pc -= 2;
//!         }
//!         mem[*pc] = mem[*pc].wrapping_sub(1);
//!     }
//!     *pc += 1;
//!     if mem.len() <= *pc {
//!         mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!     }
//!     mem[*pc] = mem[*pc].wrapping_add(2);
//!     *pc += 2;
//!     if mem.len() <= *pc {
//!         mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!     }
//!     mem[*pc] = mem[*pc].wrapping_add(1);
//!     if *pc < 1 {
//!         panic!("BrainFuck Program Counter reduced to below zero !!!");
//!     } else {
//!         *pc -= 1;
//!     }
//!     while mem[*pc] != 0 {
//!         mem[*pc] = mem[*pc].wrapping_sub(1);
//!         while mem[*pc] != 0 {
//!             *pc += 2;
//!             if mem.len() <= *pc {
//!                 mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!             }
//!             mem[*pc] = mem[*pc].wrapping_add(1);
//!             if *pc < 2 {
//!                 panic!("BrainFuck Program Counter reduced to below zero !!!");
//!             } else {
//!                 *pc -= 2;
//!             }
//!             mem[*pc] = mem[*pc].wrapping_sub(1);
//!         }
//!         mem[*pc] = mem[*pc].wrapping_add(1);
//!         *pc += 2;
//!         if mem.len() <= *pc {
//!             mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!         }
//!     }
//!     *pc += 1;
//!     if mem.len() <= *pc {
//!         mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!     }
//!     mem[*pc] = mem[*pc].wrapping_add(1);
//!     while mem[*pc] != 0 {
//!         mem[*pc] = mem[*pc].wrapping_sub(1);
//!         if *pc < 3 {
//!             panic!("BrainFuck Program Counter reduced to below zero !!!");
//!         } else {
//!             *pc -= 3;
//!         }
//!         while mem[*pc] != 0 {
//!             mem[*pc] = mem[*pc].wrapping_sub(1);
//!             *pc += 1;
//!             if mem.len() <= *pc {
//!                 mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!             }
//!             while mem[*pc] != 0 {
//!                 mem[*pc] = mem[*pc].wrapping_add(1);
//!                 while mem[*pc] != 0 {
//!                     mem[*pc] = mem[*pc].wrapping_sub(1);
//!                 }
//!                 mem[*pc] = mem[*pc].wrapping_add(1);
//!                 *pc += 1;
//!                 if mem.len() <= *pc {
//!                     mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!                 }
//!                 mem[*pc] = mem[*pc].wrapping_add(2);
//!                 *pc += 3;
//!                 if mem.len() <= *pc {
//!                     mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!                 }
//!                 mem[*pc] = mem[*pc].wrapping_sub(1);
//!                 if *pc < 2 {
//!                     panic!("BrainFuck Program Counter reduced to below zero !!!");
//!                 } else {
//!                     *pc -= 2;
//!                 }
//!             }
//!             if *pc < 1 {
//!                 panic!("BrainFuck Program Counter reduced to below zero !!!");
//!             } else {
//!                 *pc -= 1;
//!             }
//!             while mem[*pc] != 0 {
//!                 if *pc < 1 {
//!                     panic!("BrainFuck Program Counter reduced to below zero !!!");
//!                 } else {
//!                     *pc -= 1;
//!                 }
//!             }
//!             *pc += 2;
//!             if mem.len() <= *pc {
//!                 mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!             }
//!             mem[*pc] = mem[*pc].wrapping_add(6);
//!             while mem[*pc] != 0 {
//!                 if *pc < 2 {
//!                     panic!("BrainFuck Program Counter reduced to below zero !!!");
//!                 } else {
//!                     *pc -= 2;
//!                 }
//!                 mem[*pc] = mem[*pc].wrapping_add(5);
//!                 *pc += 2;
//!                 if mem.len() <= *pc {
//!                     mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!                 }
//!                 mem[*pc] = mem[*pc].wrapping_sub(1);
//!             }
//!             mem[*pc] = mem[*pc].wrapping_add(1);
//!             if *pc < 2 {
//!                 panic!("BrainFuck Program Counter reduced to below zero !!!");
//!             } else {
//!                 *pc -= 2;
//!             }
//!             mem[*pc] = mem[*pc].wrapping_add(2);
//!             print!("{}", mem[*pc] as char);
//!             while mem[*pc] != 0 {
//!                 mem[*pc] = mem[*pc].wrapping_sub(1);
//!             }
//!             if *pc < 2 {
//!                 panic!("BrainFuck Program Counter reduced to below zero !!!");
//!             } else {
//!                 *pc -= 2;
//!             }
//!         }
//!         *pc += 1;
//!         if mem.len() <= *pc {
//!             mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!         }
//!         print!("{}", mem[*pc] as char);
//!         *pc += 1;
//!         if mem.len() <= *pc {
//!             mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!         }
//!         mem[*pc] = mem[*pc].wrapping_add(1);
//!         while mem[*pc] != 0 {
//!             *pc += 2;
//!             if mem.len() <= *pc {
//!                 mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!             }
//!         }
//!         *pc += 1;
//!         if mem.len() <= *pc {
//!             mem.append(&mut vec![0; *pc - mem.len() + 1]);
//!         }
//!         mem[*pc] = mem[*pc].wrapping_add(1);
//!     }
//! });
//! ```


pub use bflib_proc_macro::brain_fuck;

/// Represents a brainfuck codeblock
/// ```
/// brain_fuck!(
///     ++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.
///     >---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.
/// )
/// ```
pub struct BrainfuckBlock {
    code: &'static dyn Fn(&mut usize, &mut Vec<u8>),
    opt_env: Option<(usize, Vec<u8>)>,
    runned: bool
}

impl BrainfuckBlock {
    /// Constructor of `BrainfuckBlock`
    /// 
    /// receives output of proc marco
    /// 
    /// **HUMAN NEVER USE**
    pub fn new(code: &'static dyn Fn(&mut usize, &mut Vec<u8>)) -> BrainfuckBlock {
        BrainfuckBlock { code, opt_env: None, runned: false }
    }
    /// Sets the Program Counter `pc` and Memory `mem` of the Brainfuck codeblock
    /// Returns self
    pub fn env(mut self, pc: usize, mem: Vec<u8>) -> Self {
        self.opt_env = Some((pc, mem));
        self
    }
}

impl Into<(usize, Vec<u8>)> for BrainfuckBlock {
    /// obtain `(pc: usize, mem: Vec<u8>)` after running
    fn into(mut self) -> (usize, Vec<u8>) {
        self.runned = true;
        let mut pc = 0;
        let mut mem = vec![];
        (self.code)(&mut pc, &mut mem);
        (pc, mem)
    }
}

impl Drop for BrainfuckBlock {
    /// runs the code on dropping if the block never runned
    /// 
    /// Case:
    /// ```
    /// brain_fuck!(
    ///     ++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.
    ///     >---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.
    /// );
    /// ```
    fn drop(&mut self) {
        if !self.runned {
            match self {
                BrainfuckBlock { code, opt_env: Some((pc, mem)), runned: false } => {
                    code(pc, mem);
                },
                BrainfuckBlock { code, opt_env: None, runned: false } => {
                    code(&mut 0, &mut vec![]);
                },
                BrainfuckBlock {runned: true, .. } => {}
            }
        }
    }
}