Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

docs: add rationale for floordiv rounding behavior #3845

Merged
merged 2 commits into from
Mar 8, 2024
Merged

docs: add rationale for floordiv rounding behavior #3845

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
8feaf50
docs: add rationale for floordiv rounding behavior
charles-cooper Mar 7, 2024
4b5eb25
fix formatting
charles-cooper Mar 7, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion docs/types.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -132,7 +132,7 @@ Shifting is only available for 256-bit wide types. That is, ``x`` must be ``int2
While at runtime shifts are unchecked (that is, they can be for any number of bits), to prevent common mistakes, the compiler is stricter at compile-time and will prevent out of bounds shifts. For instance, at runtime, ``1 << 257`` will evaluate to ``0``, while that expression at compile-time will raise an ``OverflowException``.

.. note::
Integer division has different rounding semantics than Python for negative numbers: Vyper rounds towards zero, while Python rounds towards negative infinity. For example, ``-1 // 2` will return ``-1`` in Python, but ``0`` in Vyper.
Integer division has different rounding semantics than Python for negative numbers: Vyper rounds towards zero, while Python rounds towards negative infinity. For example, ``-1 // 2`` will return ``-1`` in Python, but ``0`` in Vyper. This preserves the spirit (but not the text!) of the reasoning for Python's round-towards-negative-infinity behavior, which is that the behavior of ``//`` combined with the behavior of ``%`` preserves the following identity no matter if the quantities are negative or non-negative: ``(x // y) * y + (x % y) == x``.

.. index:: ! uint, ! uintN, ! unsigned integer

Expand Down
Loading