WRT python strings: I'm not sure what you are getting at.
Why use the { }, but then also have the double quotes? "Hello {" expr "} World"
For instance, this works - by keeping the value inside the string
print(f"string expression={1}\n")
What you showed looks to me like SlickC style - implicit concat, I didn't know other languages that do it that way:
print(f"string expression={"1"}\n")
In java you might do
String a = "Hello" + str(5) + "World";
While the same in SlickC is
_str a = "Hello" 5 "World";
And it my latest language I've been working in, "R" (really powerful, yet oh, so ugly)
a = paste("Hello", 5, "World", sep = "")
Certainly python strings are screwy in other ways, so I'm willing to believe that they are messed up in this way to.
The one that irritates me the most is that backslash (\) kind-of escapes a quote inside of a raw string.
a=R"abc\def" # A is 7 characters - as expected
a=R"abc\"def" # A is 8 characters - as expected
a=R"abc\"def\" # Syntax error - that last quote is escaped! (WTF?)