Re: Learning the match-syntax...

[swedebugia]

Hej :)

On 2019-01-06 22:36, Chris Marusich wrote:
> address@hidden writes:
>
> > I'm trying very hard to learn the guile match-syntax.
>
> When I first learned about "match", I found the Guile documentation to
> be insufficient.  It is good as a reference, though.
>
> I recommend looking beyond the Guile reference manual for a tutorial.
> Check the Guile source for "match" related things. 

Good idea.

> Also, look at
> introductions to "match" from other Schemes, such as Racket.  I think
> you will understand it better by doing that.

Thanks I already did that actually. The Racket guide was way better but 
not enough. Now I finally crossed the threshold to partially 
understanding it.

e.g.
(match '(1 2 "y" "x")
  (1
   'one)
  (number
   'number))

Will match any number for the first clause and any string for the 
second. It ONLY checks if it is a number.

To actually match something e.g. the "x" literally we need to nest the 
match like this:

(match '(1 2 y x)
  (string
   (match string
        ("x"
          'x!)))
  (number
   'number))

Positional arguments work like this:

(match '(1 2 y x)
  ;match the third item
  (_ _ string
   ;check if it is the literal "x"
   (match string
        ("x"
          'x!)))
  (number
   'number))

Correct?

--
Cheers Swedebugia