shishantbiswas/c3c
1
1
Fork 0
mirror of https://github.com/c3lang/c3c.git synced 2026-02-27 12:01:16 +00:00
Code Issues Packages Projects Releases Wiki Activity

Updated cast rules

Browse Source
This commit is contained in:
Christoffer Lerno
2024-11-19 00:04:10 +01:00
parent dd06dfa5ba
commit 489bb70901
1 changed files with 178 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

239
resources/castrules.md
View File

@@ -1,79 +1,196 @@
Some short names: ## Special rules for distinct types
1. expl - explicit
2. sw/sn - simple widening + subexpression narrowing 1. Implicit conversion will happen from constant values that can be implicitly converted to the underlying type.
3. yes - always allowed 2. Implicit conversion will happen to the underlying type if inline.
4. explptr - explicit if pointer sized
5. ptrconv - to/from void* is fine, other cast must be explicit ## Special rules for vectors
6. saconv - explicit if same element size
7. explbase - explicit to base disregaring sign 1. Implicit conversion will happen for non-vector numeric types, bools and pointers for init only.
8. distel - explicit to same element disregarding distinct 2. Explicit conversion is available in all other cases.
9. inline - implicit if type subtype
10. cond - implicit in cond, explicit otherwise ## Special rules for bool conversion in conditionals
11. edist - explicit to anything underlying type can convert to, if inline as underlying
12. arve - if array or vec ptr Types that may convert to a bool, will implicitly do so in a conditional.
### Bool ### Bool
1. Explicitly convert to float, int, bool vector #### Implicit conversion
2. Implicitly convert to bool vector init None
3. Implicitly convert to distinct bool if constant value.
#### Explicit conversion
1. To float => 0.0 and 1.0
2. To int => 0 and 1 (note, there is an argument for ~0 instead)
### Int ### Int
1. Implicitly convert to unsigned counterpart #### Implicit conversion
2. Implicitly convert to float / wider int for simple expressions.
3. Implicitly convert to same int vector init (or any?) 1. To float if simple expression
4. Explicitly convert to pointer if pointer sized 2. To wider int if simple expression
5. Explicitly convert to same size int vector, enum with same backing size, bitstruct with same backing size.
6. Explicitly convert to bool, any int or float. #### Explicit conversion
7. Implicitly convert to bool in conditionals.
8. Implicitly convert to any distinct integer. (Same size only?) 1. To bool/float/int always works
9. Implicitly convert to any float/int/distinct float/int if constant value that fits. 2. To pointer if the int is pointer sized
3. To enum (const will be range checked)
4. To bitstruct if size matches
5. To bool
### Float ### Float
1. Implicitly convert to wider float for simple expressions. #### Implicit conversion
2. Implicitly convert to same float vector init (or any?)
3. Explicitly convert to bool, any int or float.
4. Explicitly convert to any distinct float. (Same size only?)
5. Implicitly convert to any float / distinct float constant value that fits.
### Non void* pointer 1. To wider float if simple expression
1. Implicitly convert to void* and `any`. #### Explicit conversion
2. Implicitly convert to an interface if the pointee implements the interface.
3. Explicitly convert to pointer sized int.
4. Implicitly convert to slice if it is a pointer to a vector or array.
5. Explicitly convert to any other pointer.
6. Explicitly convert to any distinct pointer.
### void* pointer 1. To int / float
2. To bool
1. Implicitly convert to a pointer sized int. ### Non "void\*" pointer
2. Implicitly convert to any other pointer.
3. Explicitly convert to any distinct pointer. #### Implicit conversion
4. Implicitly convert to any distinct pointer if constant value.
1. To void*
2. To `any`
3. To slice if it is a pointer to a vector or array
4. To an interface if the pointee implements the interface.
#### Explicit conversion
1. To any pointer
2. To any interface
3. To an int size pointer
4. To bool
### "void\*" pointer
#### Implicit conversion
1. To any pointer
#### Explicit conversion
1. To a pointer sized int.
2. To bool
### Slice ### Slice
1. Implicitly convert to a pointer of the same type. #### Implicit conversion
2.
1. To a pointer of the same base pointer. For constant strings the ichar and char are equivalent.
2. To an array or vector of the same compile time known length if the array/vector conversion exists.
| from, to | bool | int | float | pointer | subarr | vec | bits | distc | array | struct | union | any | fault | enum | typeid | #### Explicit conversion
|----------|--------|----------|--------|---------|--------|----------|----------|-------|----------|--------|--------|--------|--------|--------|--------|
| bool | n/a | expl | expl | no | no | expand | no | edist | no | no | no | no | no | no | no | 1. To a pointer of the same structure.
| int | cond | sw/sn | always | explptr | no | expand | explbase | edist | no | no | no | no | no | edist | no | 2. To a slice of the same structure.
| float | cond | expl | sw/sn | no | no | expand | no | edist | no | no | no | no | no | no | no | 3. To an array of the vector of the same compile time known length if the explicit array/vector conversion exists.
| pointer | cond | explptr | no | ptrconv | arve | expand | no | edist | no | no | no | yes | expl | no | expl |
| slice | cond | no | no | no | saconv | no | no | edist | no? | no | no | no | no | no | no | ### Vector
| vec | cond | no | no | no | no | as base | no | edist | expl | no | no | no | no | no | no |
| bits | no | explbase | no | no | no | no | no? | edist | explbase | no | no | no | no | no | no | #### Implicit conversion
| distc | edist | edist | edist | edist | edist | edist | edist | edist | edist | edist | edist | edist | edist | edist | edist |
| array | no | no | no | no | no | explbase | explbase | edist | distel | no | no | no | no | no | no | 1. To a slice of the same type *if* the vector is constant.
| struct | inline | inline | inline | inline | inline | inline | inline | edist | inline | inline | inline | inline | inline | inline | inline | 2. To another vector if the base type conversion is implicit
| union | no | no | no | no | no | no | no | edist | no | no | no | no | no | no | no | 3. To an array if the conversion would work if this was an array -> array conversion.
| any | cond | no | no | expl | no | no | no | edist | no | no | no | n/a | no | no | no |
| fault | cond | explptr | no | expl | no | no | no | edist | no | no | no | no | anyf | no | no | #### Explicit conversion
| enum | no | expl | no | no | no | expand | no | edist | no | no | no | no | no | no | no |
| typeid | cond | no | no | expl | no | no | no | edist | no | no | no | no | no | no | n/a | 1. To a slice of the same structural equivalent type *if* the vector is constant.
2. To another vector if the base type conversion is valid.
3. To an array if the conversion would work if this was an explicit array -> array conversion.
### Array
#### Implicit conversion
1. To a slice of the same type *if* the array is constant.
2. To another array of the same length but with compatible types.
3. To a vector if the conversion would work if this was an array -> array conversion.
#### Explicit conversion
1. To a slice of the same structural equivalent type *if* the array is constant.
2. To another array of the same length with structurally equivalent elements.
3. To a vector if the conversion would work if this was an explicit array -> array conversion.
### Bitstruct
#### Implicit conversion
None
#### Explicit conversion
1. To the underlying type (integer or char array).
2. To bool
### Struct
#### Implicit conversion
1. To inline member
#### Explicit conversion
None
### Union
No conversions
### "any"
#### Implicit conversion
1. To `void*`
#### Explicit conversion
1. To any interface
2. To any pointer
3. To bool
### Interface
#### Implicit conversion
1. To `void*`
2. To `any`
2. To a parent interface
#### Explicit conversion
1. To any other interface
2. To any pointer
3. To bool
### Fault
#### Implicit conversion
1. To `anyfault`
#### Explicit conversion
1. To a pointer sized int
2. To bool
3. To pointer
### "anyfault"
#### Explicit conversion
1. To a pointer sized int
2. To bool
3. To pointer
4. To a `fault`
### "typeid"
#### Explicit conversion
1. To a pointer size int
2. To bool
3. To pointer