On Friday, 26 January 2018 at 11:32:42 UTC, Mike Parker wrote:
On Friday, 26 January 2018 at 11:18:21 UTC, Oleksii Skidan
wrote:
I could imagine a mixin-based solution in D:
```d
// Usage:
ASSERT!"a == b";
```
But it seems a bit alien to me. First of all, it kind of
stringly-typed one. Secondly, neither IDEs nor advanced text
editors are able to figure out that the string contains actual
D code, and so neither syntax highlighting nor code assistance
work with this approach.
Token strings are intended for this and editors *should*
highlight them (don't know if any currently do):
https://dlang.org/spec/lex.html#token_strings
Seems like I have to add some context into this conversation: I'm
writing a poor man's testing framework, since it's the best and
easiest way to learn D ;-)
I'm trying to achieve something similar to
`Catch2``REQUIRE`macro. To be honest, I did not know about toking
strings until today, and I don't know D much. Here's what I came
up with so far:
```d
string require(string expr)(string file = __FILE__, int line =
__LINE__)
{
import std.array, std.conv;
return q{
if (!($expr)) {
import std.stdio;
writeln("Test failed @", `$file`, ":", $line, "\n",
" Expected: `", `$expr`, "` to be
`true`.\n");
}
}.replace("$expr", expr)
.replace("$file", file)
.replace("$line", to!string(line));
}
```
That code snippet uses token strings to compose an if statement
that basically checks whether the given condition holds. That
looks okay-ish to me, the usage of that function is not pretty
though:
```d
unittest
{
mixin(require!q{false}); // This test will fail.
}
```
It would be awesome if I could write something like the this
instead:
```d
unittest
{
require!q{false};
}
```
At first glance it seems like I could have moved the `mixin`
statement into the `require` function itself, but that would not
really work. Consider the following snippet:
```d
unittest
{
float value = 3f;
require!q{value == 3f}; // This line won't compile.
}
```
That code won't even compile, since `value` exists in `unittest`
scope, which is not visible to the `require` function.
--
Oleksii
