zig/test/cases/reflection.zig

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const assert = @import("std").debug.assert;
const mem = @import("std").mem;
const reflection = this;
test "reflection: array, pointer, nullable, error union type child" {
comptime {
assert(([10]u8).Child == u8);
assert((*u8).Child == u8);
assert((error!u8).Payload == u8);
assert((?u8).Child == u8);
}
}
test "reflection: function return type, var args, and param types" {
comptime {
assert(@typeOf(dummy).ReturnType == i32);
assert(!@typeOf(dummy).is_var_args);
assert(@typeOf(dummy_varargs).is_var_args);
assert(@typeOf(dummy).arg_count == 3);
assert(@ArgType(@typeOf(dummy), 0) == bool);
assert(@ArgType(@typeOf(dummy), 1) == i32);
assert(@ArgType(@typeOf(dummy), 2) == f32);
}
}
fn dummy(a: bool, b: i32, c: f32) i32 {
return 1234;
}
fn dummy_varargs(args: ...) void {}
test "reflection: struct member types and names" {
comptime {
assert(@memberCount(Foo) == 3);
assert(@memberType(Foo, 0) == i32);
assert(@memberType(Foo, 1) == bool);
assert(@memberType(Foo, 2) == void);
assert(mem.eql(u8, @memberName(Foo, 0), "one"));
assert(mem.eql(u8, @memberName(Foo, 1), "two"));
assert(mem.eql(u8, @memberName(Foo, 2), "three"));
}
}
test "reflection: enum member types and names" {
comptime {
assert(@memberCount(Bar) == 4);
assert(@memberType(Bar, 0) == void);
assert(@memberType(Bar, 1) == i32);
assert(@memberType(Bar, 2) == bool);
assert(@memberType(Bar, 3) == f64);
assert(mem.eql(u8, @memberName(Bar, 0), "One"));
assert(mem.eql(u8, @memberName(Bar, 1), "Two"));
assert(mem.eql(u8, @memberName(Bar, 2), "Three"));
assert(mem.eql(u8, @memberName(Bar, 3), "Four"));
}
}
test "reflection: @field" {
var f = Foo{
.one = 42,
.two = true,
.three = void{},
};
assert(f.one == f.one);
assert(@field(f, "o" ++ "ne") == f.one);
assert(@field(f, "t" ++ "wo") == f.two);
assert(@field(f, "th" ++ "ree") == f.three);
assert(@field(Foo, "const" ++ "ant") == Foo.constant);
assert(@field(Bar, "O" ++ "ne") == Bar.One);
assert(@field(Bar, "T" ++ "wo") == Bar.Two);
assert(@field(Bar, "Th" ++ "ree") == Bar.Three);
assert(@field(Bar, "F" ++ "our") == Bar.Four);
assert(@field(reflection, "dum" ++ "my")(true, 1, 2) == dummy(true, 1, 2));
@field(f, "o" ++ "ne") = 4;
assert(f.one == 4);
}
const Foo = struct {
const constant = 52;
one: i32,
two: bool,
three: void,
};
const Bar = union(enum) {
One: void,
Two: i32,
Three: bool,
Four: f64,
};