2. Compilation Model

A program is compiled as a whole. Every module is parsed, resolved and type-checked before any code runs, and @comptime values are computed at build time (§14).

Exposed execution modes#

The compiled program runs in one of two ways:

• on the Vader virtual machine, with vader run and vader test;
• as a native binary, through generated C and the system C compiler, with vader build.

A WebAssembly target is planned (§17). The command line is described in docs/TOOLING.md.

Run-time checks#

The program stops, in every build mode, when:

• an array index is out of bounds;
• an integer division or remainder has a zero divisor;
• a conversion into a range type, an enum or char gets a value outside the target type (Hour(x), E(x), char(x)).

INT_MIN / -1 gives INT_MIN. A float division follows IEEE 754 and can give inf or nan.

An integer +, -, * or unary - that overflows also stops the program, except in a release build, where it wraps (§4 Integer overflow).

There is no null check at run time: narrowing settles nullability at compile time.