Type Conversions

Type Conversion rules

Terms

• Conversion refers to any change from one type to another.
• Coercion refers to implicit conversions.
• Casting refers to explicit conversions.
• Max Value is the largest representable value for Integers. For Enums the Max Value is the value assigned to the last case.
• Numeric refers to both Integer & Float types.

Coercion (Implicit)

Rules

Source Type(s)	Target Type	Condition(s)
All	Any
All	Union	Target Union contains a member of Source Type
Numeric, Pointer	Boolean
Integer	Float
Integer	Integer	Sign matches and Target is Larger
Signed	Unsigned	Source is a positive constant less than Target's Max Value
Unsigned	Signed	Target's Max Value is larger than the Source's
		Source is a constant less than Target's Max Value
Pointer	Pointer	Either Source or Target is Rawptr
Enum	Integer	Target's Max Value is larger than the Source's

Cast (Explicit)

Rules

Source Type(s)	Target Type	Condition(s)
All	Any
All	Union	Union contains a member of Source Type
Numeric, Pointer	Boolean
Numeric	Numeric
Pointer	Pointer
Pointer	Intptr, Uintptr
Intptr, Uintptr	Pointer
Function	Pointer
Pointer	Function
Enum	Integer
Integer	Enum

Notes

• When converting between Signed integer types Sign extension to the target type occurs.
• When converting from Signed to Unsigned integers the memory is simply reinterpreted. This has no runtime cost.
• When converting from a Float to an Integer the fraction is discarded. (round down)
• When converting to a Float type the value is rounded to the precision of that type.
  • Note that this is the only case where loss of information may occur during coercion.