wast 33.0.0

Customizable Rust parsers for the WebAssembly Text formats WAT and WAST
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

use crate::ast::{kw, Float32, Float64, Index, HeapType};
use crate::parser::{Parse, Parser, Result};

/// An expression that is valid inside an `assert_return` directive.
///
/// As of https://github.com/WebAssembly/spec/pull/1104, spec tests may include `assert_return`
/// directives that allow NaN patterns (`"nan:canonical"`, `"nan:arithmetic"`). Parsing an
/// `AssertExpression` means that:
/// - only constant values (e.g. `i32.const 4`) are used in the `assert_return` directive
/// - the NaN patterns are allowed (they are not allowed in regular `Expression`s).
#[derive(Debug)]
#[allow(missing_docs)]
pub enum AssertExpression<'a> {
    I32(i32),
    I64(i64),
    F32(NanPattern<Float32>),
    F64(NanPattern<Float64>),
    V128(V128Pattern),

    RefNull(Option<HeapType<'a>>),
    RefExtern(u32),
    RefFunc(Option<Index<'a>>),

    // Either matches an f32 or f64 for an arithmetic nan pattern
    LegacyArithmeticNaN,
    // Either matches an f32 or f64 for a canonical nan pattern
    LegacyCanonicalNaN,
}

impl<'a> Parse<'a> for AssertExpression<'a> {
    fn parse(parser: Parser<'a>) -> Result<Self> {
        let keyword = parser.step(|c| match c.keyword() {
            Some(pair) => Ok(pair),
            None => Err(c.error("expected a keyword")),
        })?;

        match keyword {
            "i32.const" => Ok(AssertExpression::I32(parser.parse()?)),
            "i64.const" => Ok(AssertExpression::I64(parser.parse()?)),
            "f32.const" => Ok(AssertExpression::F32(parser.parse()?)),
            "f64.const" => Ok(AssertExpression::F64(parser.parse()?)),
            "v128.const" => Ok(AssertExpression::V128(parser.parse()?)),
            "ref.null" => Ok(AssertExpression::RefNull(parser.parse()?)),
            "ref.extern" => Ok(AssertExpression::RefExtern(parser.parse()?)),
            "ref.func" => Ok(AssertExpression::RefFunc(parser.parse()?)),
            _ => Err(parser.error("expected a [type].const expression")),
        }
    }
}

/// Either a NaN pattern (`nan:canonical`, `nan:arithmetic`) or a value of type `T`.
#[derive(Debug, PartialEq)]
#[allow(missing_docs)]
pub enum NanPattern<T> {
    CanonicalNan,
    ArithmeticNan,
    Value(T),
}

impl<'a, T> Parse<'a> for NanPattern<T>
where
    T: Parse<'a>,
{
    fn parse(parser: Parser<'a>) -> Result<Self> {
        if parser.peek::<kw::nan_canonical>() {
            parser.parse::<kw::nan_canonical>()?;
            Ok(NanPattern::CanonicalNan)
        } else if parser.peek::<kw::nan_arithmetic>() {
            parser.parse::<kw::nan_arithmetic>()?;
            Ok(NanPattern::ArithmeticNan)
        } else {
            let val = parser.parse()?;
            Ok(NanPattern::Value(val))
        }
    }
}

/// A version of `V128Const` that allows `NanPattern`s.
///
/// This implementation is necessary because only float types can include NaN patterns; otherwise
/// it is largely similar to the implementation of `V128Const`.
#[derive(Debug)]
#[allow(missing_docs)]
pub enum V128Pattern {
    I8x16([i8; 16]),
    I16x8([i16; 8]),
    I32x4([i32; 4]),
    I64x2([i64; 2]),
    F32x4([NanPattern<Float32>; 4]),
    F64x2([NanPattern<Float64>; 2]),
}

impl<'a> Parse<'a> for V128Pattern {
    fn parse(parser: Parser<'a>) -> Result<Self> {
        let mut l = parser.lookahead1();
        if l.peek::<kw::i8x16>() {
            parser.parse::<kw::i8x16>()?;
            Ok(V128Pattern::I8x16([
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
            ]))
        } else if l.peek::<kw::i16x8>() {
            parser.parse::<kw::i16x8>()?;
            Ok(V128Pattern::I16x8([
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
            ]))
        } else if l.peek::<kw::i32x4>() {
            parser.parse::<kw::i32x4>()?;
            Ok(V128Pattern::I32x4([
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
            ]))
        } else if l.peek::<kw::i64x2>() {
            parser.parse::<kw::i64x2>()?;
            Ok(V128Pattern::I64x2([parser.parse()?, parser.parse()?]))
        } else if l.peek::<kw::f32x4>() {
            parser.parse::<kw::f32x4>()?;
            Ok(V128Pattern::F32x4([
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
                parser.parse()?,
            ]))
        } else if l.peek::<kw::f64x2>() {
            parser.parse::<kw::f64x2>()?;
            Ok(V128Pattern::F64x2([parser.parse()?, parser.parse()?]))
        } else {
            Err(l.error())
        }
    }
}