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Martin Fowler’s Syntactic Noise

Updated Saturday, April 4th, 2009

A possible translation of Martin Fowler's Syntactic Noise:

(state-machine idle
  (events
    (door-closed D1CL)
    (draw-opened D2OP)
    (light-on    L1ON))

  (commands
    (lock-panel  PNLK)
    (unlock-door D1UL))

  (state idle
    (=> door-closed active)
    (actions unlock-door
             lock-panel))

  (state active
    (=> draw-opened waiting-for-light)
    (=> light-on    waiting-for-draw)))

Put in a blender together with about 3 dl macrology, mix well.

Responses

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Robert Kasanicky said on June 24th, 2008 at 14:08 (link)

Most of the ‘noisy’ parentheses are not strictly necessary, indentation alone can work too - see http://www.lispin.org/
Mikael Jansson said on June 24th, 2008 at 14:17 (link)

Three things:

1. You already do look at the indentation level, and not the parens;
2. … moreover, most people change the paren color so they are close to the background color, making them actually disappear (mine are dark gray against a black background);
3. the output of the parens inserter is awful:
```
(defun factorial (n)
  (if (<= n 1)
    (the 1
    )(* n
      (factorial (- n 1)
))))
```
Nobody would indent their code nor place their parens like that. Instead, they would write:
```
(defun factorial (n)
  (if (<= n 1)
      (the 1)
      (* n (factorial (- n 1)))))
```
Frankly, I don’t see the point of the Lispin project. But, to each his own!
Bill Birch said on July 31st, 2008 at 15:08 (link)

Yes there are two kinds of programmers those who are happy with () and those that ain’t.
Personally I was happy with most of the (), but it puts off most developers, including
many THWers! Hence I decided to build a parser which removed most of the parens so the majority of coders would not turn up their noses.

The latest incarnation is in Genyris (http://sourceforge.net/projects/genyris/). This time the language is modified to suit indentation’s constraints, it looks like Ruby without ends. The rule is: If the indentation looks right the code will be too.

e.g.
```
class Person ()
   def !valid? (obj)
      obj
         bound? !age
 
class Boomer (Person)
   def !valid? (obj)
      obj
         between 45 !age 60
 
class Hippie (Boomer)
   def !valid? (obj)
      obj
         bound? !bong
 
define noel
  dict
     !name: "Noel"
     !age: 49
     !bong: true
 
classify Person noel
 
assert
  and
    is-instance? noel Hippie
```

Bill Birch said on July 31st, 2008 at 15:16 (link)

So MF’s example in Genyris:

state-machine idle 
  events
    door-closed D1CL
    draw-opened D2OP
    light-on    L1ON
 
  commands
    lock-panel  PNLK
    unlock-door D1UL
 
  state idle
    = door-closed active
    actions unlock-door lock-panel
 
  state active
    = draw-opened waiting-for-light
    = light-on    waiting-for-draw

Which is more readable to a non-Lisper?

Mikael Jansson said on October 2nd, 2008 at 14:10 (link)

Looks alright, but the question is how user-extensible it is. Can you do macros?
Bill Birch said on October 5th, 2008 at 03:55 (link)

Yes. Macros and templates.