Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.postscript > #3032

Re: functional ps? was: Re: html generator

Show all headers | View raw

[luser droog <luser.droog@gmail.com>, 2017-03-31 23:48]
[...]
> Subsequent iterations and conversations have steered the project
> somewhat away from the object-orientation paradigm (although of
> course that will be important in the js of the resulting page)
> towards being more 'functional'. So the following is a grab-bag
> of stuff which is my attempt to rewrite some postscript without
> following my usual style.
> 
> Any comments (positive or negative) appreciated.
> 
> 
> $ cat toolbox.ps
> 
> /toolbox-main {
>     4 5 6 {a b c} BEGIN

I find this unnecessary. What's the advantage over << /a 4 /b 5 /c 6 >> begin?
For assigning parameters, I prefer your idiom ({ c b a } { exch def } forall),
or a better abstraction, maybe something like

  /pythagorean-distance { x0 y0 x1 y1 } {
       ...
  } defn

[...]

> /backward-for-loop {                            % a proc
>     exch backwards                              % proc a n-1 -1 0
>     5 -1 roll                                   % a n-1 -1 0 proc
>     for
> } def

I had to change this to:

/backwards-for-loop {                            % a proc
    exch backwards                              % proc a n-1 -1 0
    4 -1 roll                                    % a n-1 -1 0 proc
    for
} def

[...]

> % array-of-strings  join  string
> % array-of-arrays   join  array
> % string* n         join  string
> % array* n          join  array
> %
> /join {
>     dup is_integer { array astore } if
>     join-elements
> } def

I like this implementation, it's well factored and easy to follow. I never seem
to be able to do that, I always put everything in one function.

> 
> /join-elements {                                % a
>     dup element-lengths-sum                     % a n
>     1 index new-same-type-as-first              % a a'
>     exch put-by-intervals                       % a'
> } def
> 
> /element-lengths-sum {                          % a
>     0 exch { length add } forall                % n
> } def
> 
> /type-constructor <<
>     /arraytype {array}
>     /stringtype {string}
>     /nulltype {string}
> >> def  
> 
> 
> /new-same-type-as-first {                       % n a
>     %pstack/ =
>     first type                                  % n a[0]
>     %pstack/ =
>     type-constructor exch get exec              % a a'
> } def
> 
> /first { dup length 0 eq { pop null }{ 0 get } ifelse } def
> 
> /put-by-intervals {                             % a' a
>     0 exch {                                    % a' pos a[i]
>         put-element-and-update-position         % a' pos a[i]
>     } forall                                    % a' pos'
>     pop                                         % a'
> } def
> 
> /put-element-and-update-position {              % a' pos a[i]
>     3 copy putinterval                          % a' pos a[i]
>     length add                                  % a' pos'
> } def
> 
> /is_integer { type /integertype eq } def
> /is_array   { type /arraytype   eq } def
> /is_dict    { type /dicttype    eq } def
> /is_null    { type /nulltype    eq } def
> /is_zero    { dup is_integer { 0 eq }{ false } ifelse } def
> 
> /main where { pop }{ toolbox-main } ifelse
-- 

Back to comp.lang.postscript | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

html generator luser droog <luser.droog@gmail.com> - 2017-03-21 22:44 -0700
  Re: html generator Carlos <angus@quovadis.com.ar> - 2017-03-22 22:02 +0100
    Re: html generator tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2017-03-22 18:24 -0400
      Re: html generator luser droog <luser.droog@gmail.com> - 2017-03-22 16:45 -0700
        Re: html generator JohnF <john@please.see.sig.for.email.com> - 2017-03-23 05:18 +0000
        Re: html generator tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2017-03-23 19:33 -0400
      Re: html generator Carlos <angus@quovadis.com.ar> - 2017-03-23 07:56 +0100
    Re: html generator luser droog <luser.droog@gmail.com> - 2017-03-22 16:44 -0700
  functional ps? was: Re: html generator luser droog <luser.droog@gmail.com> - 2017-03-31 23:48 -0700
    Re: functional ps? was: Re: html generator Carlos <angus@quovadis.com.ar> - 2017-04-01 23:33 +0200
      Re: functional ps? was: Re: html generator luser droog <luser.droog@gmail.com> - 2017-04-03 08:10 -0700
        Re: functional ps? was: Re: html generator luser droog <luser.droog@gmail.com> - 2017-04-07 07:07 -0700
        Re: functional ps? was: Re: html generator tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2017-04-07 22:43 -0400

csiph-web