stack_assembly/
effect.rs

1/// # An event triggered by scripts, to signal a specific condition
2///
3/// Evaluating an operator can trigger an effect. Active effects are stored in
4/// in [`Eval`]'s [`effect`] field. Please refer to the documentation of that
5/// field, for more information on effects and how to handle them.
6///
7/// [`Eval`]: crate::Eval
8/// [`effect`]: struct.Eval.html#structfield.effect
9#[derive(Debug, Eq, PartialEq)]
10pub enum Effect {
11    /// # An assertion failed
12    ///
13    /// Can trigger when evaluating `assert`, if its input is zero.
14    AssertionFailed,
15
16    /// # Tried to divide by zero
17    ///
18    /// Can trigger when evaluating the `/` operator, if its second input is
19    /// `0`.
20    DivisionByZero,
21
22    /// # Division resulted in integer overflow
23    ///
24    /// Can only trigger when evaluating the `/` operator, if its first input is
25    /// the lowest signed (two's complement) 32-bit integer, and its second
26    /// input is `-1`.
27    ///
28    /// All other arithmetic operators wrap on overflow and don't trigger this
29    /// effect.
30    IntegerOverflow,
31
32    /// # A memory address is out of bounds
33    ///
34    /// Can trigger when evaluating the `read` or `write` operators, if their
35    /// _address_ input (when interpreted as an unsigned 32-bit integer) does
36    /// not refer to an address that is within the bounds of the memory.
37    InvalidAddress,
38
39    /// # Evaluated a reference that is not paired with a matching label
40    ///
41    /// Can trigger when evaluating a reference, if that reference does not
42    /// refer to a label.
43    InvalidReference,
44
45    /// # An index that supposedly refers to a value on the stack, doesn't
46    ///
47    /// Can trigger when evaluating the `copy` or `drop` operators, if their
48    /// _index_ input is too large to refer to a value on the stack.
49    InvalidStackIndex,
50
51    /// # Ran out of operators to evaluate
52    ///
53    /// Triggers when evaluation reaches the end of the script, where no more
54    /// operators are available. This signals the regular end of the evaluation.
55    OutOfOperators,
56
57    /// # Tried popping a value from an empty stack
58    ///
59    /// Can trigger when evaluating any operator that has more inputs than the
60    /// number of values currently on the stack.
61    StackUnderflow,
62
63    /// # Evaluated an identifier that the language does not recognize
64    ///
65    /// Can trigger when evaluating an identifier, if that identifier does not
66    /// refer to a known operation.
67    UnknownIdentifier,
68
69    /// # The evaluating script yields control to the host
70    ///
71    /// Triggers when evaluating the `yield` operator.
72    Yield,
73}
stack_assembly/effect.rs

stack_assembly/
effect.rs
