For running php or sth else, it's maybe a good start to let macro {.exec.} can return stdout outputs
Edit: seems this already works:
{.exec|php\php.exe -r "$str='Hello, PHP!'; echo $str;"|out=x.}
{.^x.}
{.exec|python -c "str='Hello, Python!';print(str)"|out=y.}
{.^y.}
So is HFS already able to run php, python, and many more thing?
(With an error message corrected)
Needs to make {.exec.} more reliable. Such as
this.