John Clements wrote at 10/26/2010 02:33 AM:
Who thinks it would be helpful, though, if Check Syntax were to, say, underline
the function position?
Not for the non-beginner languages, please.
After thinking about it for a while, I'm currently of the opinion that one
serious shortcoming of our syntax is that we fail to distinguish the function
position from that of the arguments, something that the traditional f(x)
notation does pretty clearly.
FWIW, when I was first learning non-Scheme Lisps, I visualized the
function name as part of the parentheses pair. So, this is atomic
syntax for the application of function "myfunc":
(myfunc )
With some background between the parens, and elastic to accommodate
arguments, and with the name permanently fixed as part of the left
paren. Perhaps the "(myfunc" and its ")" are die-cast metal tags on the
ends of a piece of elastic or on parts of a slide rule, though I never
thought of it quite that concretely. To reinforce: the ")" are like
little handles on the very ends that you can pull and push, and they
mark the very ends, too.
When I moved to Scheme, I gave up this fairly physical notion of the
syntax, since clearly it would discourage me from thinking about
procedures as first-class objects, which Scheme seemed to consider
important.
However, if new students are somehow confused by this syntax, and you
want to teach the noble lie that procedures always have names, and
therefore that students could use the more physical/visual notion of the
syntax that always has parentheses... I suggest that the first thing to
do is to make the color of the parentheses pair match the color of the
procedure name.
Hand-wavey cog-sci: By making parens a different color, as DrRacket
does, they are more a different thing than the procedure name things,
and then we have to think more about their semantic and spatial
relationships with other things.
Optionally, in addition to making parens use the same color as their
procedures, you could then use hue or brightness or something to
indicate nesting depth or syntactic form identity, always keeping the
parens matching their procedure. (You have to explain what the color
differences mean, then, and worry about whether they interrupt reading
flow too much or complicate looking at more than one syntactic construct
thing at a time.)
Or maybe you don't have change anything in DrRacket, and instead simply
tell students some physical/visual ways to conceptualize the syntax
itself. Students who have trouble remembering the syntax could latch
onto conceptualization that works for them, til they no longer need the
training wheels. Or til you have to teach that procedure are first-class.
--
http://www.neilvandyke.org/
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