> In the help documentation, the grammatical > concepts of noun, verb, adverb and more, get used > to introduce the grammar of J. That seems effective > and I've been using something like this with OO > (not Python-specific): > > noun.adjective = value > noun.verb( ) >
Continuing with this theme, I also find it important to draw attention to the ( ) after the verb, given Python lets you mention noun.verb by name without calling it, an important distinction when writing callbacks. "The grammar of __call__" we could call it, following the practice of underlining the partly-J-inspired grammatical approach in the help docs. Here, the primitive association of "emoticon mouth" :-() <-- i.e. "mouth sideways" with "callable mouth" () e.g. __call__(), is important. To say something is "callable" is to say it "has a mouth" (in principle, even if it needs no arguments, either positional or keyword). That's the signature of a verb( ) -- which is any callable, not just "functions". The types themselves are callables e.g. enumerate, and range. "Has a mouth" is a concept like "has a face" i.e. it translates somewhat universally across human languages. None of the Python keywords have mouths i.e. keywords are not callables. When print went from being a keyword in Python 2.x to a function in Python 3.x, it only then became a callable. Beginner Python coders are apt to think of return or perhaps if, as callables: if(True): return(True) they will say, as they're thinking of if and return as callables (a mistake). The thing is, the syntax is still legal because return x return (x) return ((x)) return (((x))) ... all mean the same thing. The same confusions arise with print. print(3) works until you come to python(3, 4, sep="") with a Python 2.x interpreter: that's when the exception gets raised. Not until a keyword argument is mentioned. So just saying "return has no mouth" and/or "print has a mouth now, in newer Pythons" may be the better mnemonic to use. Kirby
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