motivating example:
```nim
iterator p(a: openArray[char]): int =
if a.len != 0:
if a[0] != '/':
discard
for t in p(""): discard
```
The compiler wants to evaluate `a[0]` at compile time even though it is
protected by the if statement above it. Similarly expressions like
`a.len != 0 and a[0] == '/'` have problems. It seems like the logic in
semfold needs to be more aware of branches to positively identify when
it is okay to fail compilation in these scenarios. It's a bit tough
though because it may be the case that non-constant expressions in
branching logic can properly protect some constant expressions.
(cherry picked from commit 850f327713)
closes https://github.com/nim-lang/RFCs/issues/554
Adds a symmetric difference operation to the language bitset type. This
maps to a simple `xor` operation on the backend and thus is likely
faster than the current alternatives, namely `(a - b) + (b - a)` or `a +
b - a * b`. The compiler VM implementation of bitsets already
implemented this via `symdiffSets` but it was never used.
The standalone binary operation is added to `setutils`, named
`symmetricDifference` in line with [hash
sets](https://nim-lang.org/docs/sets.html#symmetricDifference%2CHashSet%5BA%5D%2CHashSet%5BA%5D).
An operator version `-+-` and an in-place version like `toggle` as
described in the RFC are also added, implemented as trivial sugar.
(cherry picked from commit ae9287c4f3)
fixes#24104, refs #23955
The line `result.typ = dstTyp` added in #23955 changes the type of
`result`, which was the type of `n` due to the argument passed to
`newIntNodeT`, to the abstract type skipped `dstTyp`. The line is
removed to just keep the type as abstract.
When creating heterogenous slices of distinct types, the compiler does
not initialize the internal type's `size` before accessing it.
This then leads to this crash message:
```
compiler/int128.nim(594, 11) `false` masking only implemented for 1, 2, 4 and 8 bytes [AssertionError]
```
This patch initializes the `size` properly, fixing the problem.
* compiler/vmhooks: add getVar to allow vmops with var params
* addFloat vmops with var param
* cgen now renders float32 literals in c backend using roundtrip float to string
* code cleanups
* refactorings for IC
* more refactorings for IC
* IC: attach the 'nil' type to its module
* IC: refactorings and improvements
* IC: progress
* IC: more serialization fixes
* IC: embarrassing omission
* code cleanups
* reworked ID handling
* the packed AST now has its own ID mechanism
* basic serialization code works
* extract rodfiles to its own module
* rodfiles: store and compare configs
* rodfiles: store dependencies
* store config at the end
* precise dependency tracking
* dependency tracking for rodfiles
* completed loading of PSym, PType, etc
* removed dead code
* bugfix: do not realloc seqs when taking addr into an element
* make IC opt-in for now
* makes tcompilerapi green again
* final cleanups
Co-authored-by: Andy Davidoff <github@andy.disruptek.com>
* refactoring: idents don't need inheritance
* refactoring: adding an IdGenerator (part 1)
* refactoring: adding an IdGenerator (part 2)
* refactoring: adding an IdGenerator (part 3)
* refactoring: adding an IdGenerator (part 4)
* refactoring: adding an IdGenerator (part 5)
* refactoring: adding an IdGenerator (part 5)
* IdGenerator must be a ref type; hello world works again
* make bootstrapping work again
* progress: add back the 'exactReplica' ideas
* added back the missing exactReplica hacks
* make tcompilerapi work again
* make important packages green
* attempt to fix the build for 32 bit machines (probably need a better solution here)
* Error -> Defect for defects
The distinction between Error and Defect is subjective,
context-dependent and somewhat arbitrary, so when looking at an
exception, it's hard to guess what it is - this happens often when
looking at a `raises` list _without_ opening the corresponding
definition and digging through layers of inheritance.
With the help of a little consistency in naming, it's at least possible
to start disentangling the two error types and the standard lib can set
a good example here.
