43. Constant expression checker¶
The constexpr module implements constant expression function argument check.
All functions and symbols are in “constexpr” module, use require to get access to it.
require daslib/constexpr
43.1. Function annotations¶
-
constexpr
¶
This macro implements a constexpr function argument checker. Given list of arguments to verify, it will fail for every one where non-constant expression is passed. For example:
[constexpr (a)]
def foo ( t:string; a : int )
print("{t} = {a}\n")
var BOO = 13
[export]
def main
foo("blah", 1)
foo("ouch", BOO) // comilation error: `a is not a constexpr, BOO`