qasm 1.0.0

A OPENQASM 2.0 Parser
Documentation 
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
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382

//! This module implements the various parsing methods.
//! Most methods are not documented, and should only be accessed
//! indirectly from the `parse` method.

use token::Token;
use error::Error;
use ast::{Argument, AstNode};
use std::result;

type Result<T> = result::Result<T, Error>;

pub fn parse_node(tokens: &mut Vec<Token>) -> Result<AstNode> {
    match tokens.remove(0) {
        Token::QReg => qreg(tokens),
        Token::CReg => creg(tokens),
        Token::Barrier => barrier(tokens),
        Token::Reset => reset(tokens),
        Token::Measure => measure(tokens),
        Token::Id(i) => application(tokens, i),
        Token::Opaque => opaque(tokens),
        Token::Gate => gate(tokens),
        Token::If => if_(tokens),

        _ => Err(Error::SourceError),
    }
}

pub fn version(tokens: &mut Vec<Token>) -> Result<f32> {
    let version = match_real(tokens)?;
    match_semicolon(tokens)?;

    Ok(version)
}

pub fn qreg(tokens: &mut Vec<Token>) -> Result<AstNode> {
    // QReg -> Identifier -> Left Square Bracket -> Int -> Right Square Bracket -> Semicolon
    let identifier = match_identifier(tokens)?;

    match_token(tokens, Token::LSParen)?;

    let num = match_nninteger(tokens)?;
    match_token(tokens, Token::RSParen)?;
    match_semicolon(tokens)?;

    Ok(AstNode::QReg(identifier, num))
}

pub fn creg(tokens: &mut Vec<Token>) -> Result<AstNode> {
    // CReg -> Identifier -> Left Square Bracket -> Int -> Right Square Bracket -> Semicolon
    let identifier = match_identifier(tokens)?;

    match_token(tokens, Token::LSParen)?;

    let num = match_nninteger(tokens)?;
    match_token(tokens, Token::RSParen)?;
    match_semicolon(tokens)?;

    Ok(AstNode::CReg(identifier, num))
}

pub fn if_(tokens: &mut Vec<Token>) -> Result<AstNode> {
    match_token(tokens, Token::LParen)?;
    let id = match_identifier(tokens)?;
    match_token(tokens, Token::Equals)?;
    let val = match_nninteger(tokens)?;
    match_token(tokens, Token::RParen)?;
    let node = parse_node(tokens)?;

    Ok(AstNode::If(id, val, Box::new(node)))
}

pub fn barrier(tokens: &mut Vec<Token>) -> Result<AstNode> {
    // Barrier -> Argument -> Semicolon
    let argument = match_argument(tokens)?;
    match_semicolon(tokens)?;
    Ok(AstNode::Barrier(argument))
}

pub fn reset(tokens: &mut Vec<Token>) -> Result<AstNode> {
    // reset -> Argument -> Semicolon
    let argument = match_argument(tokens)?;
    match_semicolon(tokens)?;
    Ok(AstNode::Reset(argument))
}

pub fn measure(tokens: &mut Vec<Token>) -> Result<AstNode> {
    // Measure -> Argument -> Arrow -> Argument -> Semicolon
    let arg_1 = match_argument(tokens)?;
    match_token(tokens, Token::Arrow)?;
    let arg_2 = match_argument(tokens)?;
    match_semicolon(tokens)?;

    Ok(AstNode::Measure(arg_1, arg_2))
}

pub fn application(tokens: &mut Vec<Token>, id: String) -> Result<AstNode> {
    // id -> argument list -> Semicolon;
    // id -> () -> argument list -> Semicolon;
    // id -> ( Expr list ) ->
    let params = match match_token_peek(tokens, Token::LParen) {
        Ok(_) => {
            tokens.remove(0);
            match match_token_peek(tokens, Token::RParen) {
                Ok(_) => {
                    tokens.remove(0);
                    vec![]
                }
                Err(_) => {
                    let p = match_mathexpr_list(tokens)?;
                    match_token(tokens, Token::RParen)?;
                    p
                }
            }
        }
        Err(_) => vec![],
    };

    let list = match_argument_list(tokens)?;
    match_semicolon(tokens)?;
    Ok(AstNode::ApplyGate(id, list, params))
}

pub fn opaque(tokens: &mut Vec<Token>) -> Result<AstNode> {
    // opaque -> id -> argument list -> Semicolon;
    // opaque -> id -> () -> argument list -> Semicolon;
    // opaque -> id -> ( Expr list ) ->
    let id = match_identifier(tokens)?;
    let params = match match_token_peek(tokens, Token::LParen) {
        Ok(_) => {
            tokens.remove(0);
            match match_token_peek(tokens, Token::RParen) {
                Ok(_) => {
                    tokens.remove(0);
                    vec![]
                }
                Err(_) => {
                    let p = match_id_list(tokens)?;
                    match_token(tokens, Token::RParen)?;
                    p
                }
            }
        }
        Err(_) => vec![],
    };

    let list = match_argument_list(tokens)?;
    match_semicolon(tokens)?;
    Ok(AstNode::Opaque(id, list, params))
}

pub fn gate(tokens: &mut Vec<Token>) -> Result<AstNode> {
    // gate -> id -> argument list -> { -> list of applications -> }
    // gate -> id -> () -> argument list ->{ -> list of applications -> }
    // gate -> id -> ( Expr list ) -> { -> list of applications -> }
    let id = match_identifier(tokens)?;

    let params = match match_token_peek(tokens, Token::LParen) {
        Ok(_) => {
            tokens.remove(0);
            match match_token_peek(tokens, Token::RParen) {
                Ok(_) => {
                    tokens.remove(0);
                    vec![]
                }
                Err(_) => {
                    let p = match_id_list(tokens)?;
                    match_token(tokens, Token::RParen)?;
                    p
                }
            }
        }
        Err(_) => vec![],
    };

    let list = match_id_list(tokens)?;

    match_token(tokens, Token::LCParen)?;

    let applications = if tokens[0] != Token::RCParen {
        match_application_list(tokens)?
    } else {
        vec![]
    };

    match_token(tokens, Token::RCParen)?;

    Ok(AstNode::Gate(id, list, params, applications))
}

//////////////////////////////////////////////////////////////////////
// Terminals
//////////////////////////////////////////////////////////////////////
pub fn match_application_list(tokens: &mut Vec<Token>) -> Result<Vec<AstNode>> {
    let mut args = vec![];
    let id = match_identifier(tokens)?;

    let head = application(tokens, id)?;

    args.push(head);

    if let Token::Id(_) = tokens[0] {
        let tail = match_application_list(tokens)?;
        for t in tail {
            args.push(t);
        }
    }
    Ok(args)
}

pub fn match_argument_list(tokens: &mut Vec<Token>) -> Result<Vec<Argument>> {
    let mut args = vec![];
    let head = match_argument(tokens)?;

    args.push(head);

    if match_token_peek(tokens, Token::Comma).is_ok() {
        tokens.remove(0);
        let tail = match_argument_list(tokens)?;
        for t in tail {
            args.push(t);
        }
    }

    Ok(args)
}

pub fn match_mathexpr_list(tokens: &mut Vec<Token>) -> Result<Vec<String>> {
    let mut args = vec![];
    let head = match_mathexpr(tokens)?;

    args.push(head);

    if match_token_peek(tokens, Token::Comma).is_ok() {
        tokens.remove(0);
        let tail = match_mathexpr_list(tokens)?;
        for t in tail {
            args.push(t);
        }
    }

    Ok(args)
}

pub fn match_id_list(tokens: &mut Vec<Token>) -> Result<Vec<String>> {
    let mut args = vec![];
    let head = match_identifier(tokens)?;

    args.push(head);

    if match_token_peek(tokens, Token::Comma).is_ok() {
        tokens.remove(0);
        let tail = match_id_list(tokens)?;
        for t in tail {
            args.push(t);
        }
    }

    Ok(args)
}

pub fn match_mathexpr(tokens: &mut Vec<Token>) -> Result<String> {
    if tokens.is_empty() {
        return Err(Error::SourceError);
    }

    let mut expr_string = String::from("");
    let mut num_open_paren = 0;

    // Parse until we find a comma, semicolon or a non matching paren
    while !tokens.is_empty() {
        let string: String = match tokens[0].clone() {
            Token::Real(f) => f.to_string(),
            Token::NNInteger(n) => n.to_string(),
            Token::Id(i) => i,
            Token::Pi => String::from("pi"),
            Token::LParen => {
                num_open_paren += 1;
                String::from("(")
            }
            Token::RParen => {
                if num_open_paren == 0 {
                    return Ok(expr_string);
                }
                num_open_paren -= 1;
                String::from(")")
            }
            Token::Plus => String::from("+"),
            Token::Minus => String::from("-"),
            Token::Times => String::from("*"),
            Token::Divide => String::from("/"),
            Token::Exp => String::from("^"),
            Token::Sin => String::from("sin"),
            Token::Cos => String::from("cos"),
            Token::Tan => String::from("tan"),
            Token::Ln => String::from("ln"),
            Token::Sqrt => String::from("sqrt"),
            _ => return Ok(expr_string),
        };

        tokens.remove(0);
        expr_string.push_str(" ");
        expr_string.push_str(&string);
        expr_string.push_str(" ");
    }

    Ok(expr_string)
}

pub fn match_argument(tokens: &mut Vec<Token>) -> Result<Argument> {
    let id = match_identifier(tokens)?;

    match match_token_peek(tokens, Token::LSParen) {
        Ok(()) => {
            tokens.remove(0);
            let n = match_nninteger(tokens)?;
            match_token(tokens, Token::RSParen)?;
            Ok(Argument::Qubit(id, n))
        }
        Err(_) => Ok(Argument::Register(id)),
    }
}

pub fn match_real(tokens: &mut Vec<Token>) -> Result<f32> {
    if tokens.is_empty() {
        return Err(Error::SourceError);
    }
    match tokens.remove(0) {
        Token::Real(n) => Ok(n),
        _ => Err(Error::MissingReal),
    }
}

pub fn match_nninteger(tokens: &mut Vec<Token>) -> Result<i32> {
    if tokens.is_empty() {
        return Err(Error::SourceError);
    }
    match tokens.remove(0) {
        Token::NNInteger(n) => Ok(n),
        _ => Err(Error::MissingInt),
    }
}

pub fn match_identifier(tokens: &mut Vec<Token>) -> Result<String> {
    if tokens.is_empty() {
        return Err(Error::SourceError);
    }
    match tokens.remove(0) {
        Token::Id(s) => Ok(s),
        _ => Err(Error::MissingIdentifier),
    }
}

pub fn match_token(tokens: &mut Vec<Token>, token: Token) -> Result<()> {
    if tokens.is_empty() {
        return Err(Error::SourceError);
    }
    if tokens.remove(0) != token {
        return Err(Error::SourceError);
    }
    Ok(())
}

pub fn match_token_peek(tokens: &mut Vec<Token>, token: Token) -> Result<()> {
    if tokens.is_empty() {
        return Err(Error::SourceError);
    }
    if tokens[0] != token {
        return Err(Error::SourceError);
    }
    Ok(())
}

pub fn match_semicolon(tokens: &mut Vec<Token>) -> Result<()> {
    if tokens.is_empty() {
        return Err(Error::SourceError);
    }

    if tokens.remove(0) != Token::Semicolon {
        return Err(Error::MissingSemicolon);
    }
    Ok(())
}