Category:Initlib: Difference between revisions
Improved display of source code, enabled syntax highlighting, and fixed sloppy formatting and typos.
(Improved display of source code, enabled syntax highlighting, and fixed sloppy formatting and typos.) |
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Here is a library of functions tested in
<syntaxhighlight lang="shell" inline>
ghostscript -q -dNODISPLAY -c '(initlib.ps) run'
</syntaxhighlight>
== <code>initlib.ps</code> ==
<
%!PS
% conventions: parameter names with let begins with .
% basic definition, makes the definitions less verbose.
/. {bind def} bind def
/' {load} bind def
/reverse {{} exch {exch [3 1 roll aload pop]} forall}.
/let {dup length dict begin reverse {exch def} forall}.
/let* {reverse {exch def} forall}.
% some predicates.
/eq? {eq}.
/list? {dup type /arraytype eq?}.
/leaf? {list? not}.
/empty? {dup length 0 eq?}.
/zero? {dup 0 eq?}.
% stack invariant, execute any predicate and
% leave stack untouched except for answer.
/? {
4 dict begin
[/.pred] let*
count array astore /.stack exch def
/_restore {clear .stack aload pop}.
.stack aload pop .pred /.top exch def
_restore .top
end}.
% stacky functions
/rup {3 1 roll}.
/rdown {3 -1 roll}.
/# {exch dup rdown .makeoperator bind def} bind def
/getname {dup 0 get exch}.
/getbody {dup length 1 sub 1 exch getinterval}.
% convenience arithmetic
/+ {add}.
/- {sub}.
/* {mul}.
/\ {div}.
% lispy functions
/first {0 get}.
/car {first}.
Line 28 ⟶ 60:
/tail {dup length 1 sub get}.
/!tail {dup tail}.
/cons {[rup aload pop]
/tadd {[rup aload length 1 add -1 roll] }.
/uncons {getname getbody}.
/concat {exch [ rup aload pop counttomark -1 roll aload pop ] }.
% make a unit list.
/unit {1 array astore cvx}.
/succ {1 add}.
/pred {1 sub}.
/range {[rup exch aload pop rup exch rdown {} for]}.
% higher order thingies.
/map { [ rup forall ] }.
% [1 2 3 4] {1 add} map
/fold {rup exch rdown forall}.
%/reverse
% {} [1 2 3 4 5] {exch cons} forall
% [1 2 3 4] 0 {+} fold
% name - filter is taken so we are left with..
/find {
4 dict begin
end}.
/
[ exch {
{ {empty? exch pop} map all?} {pop exit} ift
[ exch {} {uncons {exch cons} dip exch} fold counttomark 1 roll] uncons
} loop ] {reverse} map
}.
/zip {[rup] transpose}.
% [[1 2 3 4 ] [5 6 7 8] [9 10 11 12]] transpose
/all? {
{
{empty?} ? {pop true exit} if
uncons {?} dip exch not {pop false exit} if
} loop
}.
% 1 {{10 gt} {5 gt} {0 gt}} any?
/any? {
{
{empty?} ? {pop false exit} if
uncons {?} dip exch {pop true exit} if
} loop
}.
/pipe {
{
{empty?} ? {pop exit} if
uncons {i} dip
} loop
}.
% 1 {{2 *} {3 *} {5 *}} pipe
/collect {
{
{empty?} ? {pop exit} if
uncons {?} dip
} loop
}.
% 1 {{2 *} {3 *} {5 *}} collect
% do on all elements of a tree.
/treemap {
[/.tree /.rec] let
/.tree '
{leaf?} /.rec '
{{empty?} {}
{dup
{first /.rec ' treemap} dip
{rest /.rec ' treemap} i cons}
ifte}
ifte
end}.
% control structures
% ift - allow stack invariant if condition
/ift {
[/.if /.then] let
/.if ' ? /.then ' if
end}.
% ift - allow stack invariant ifelse condition
/ifte {
[/.if /.then /.else] let
/.if ' ?
end}.
% switch statement.
/is? {{exit} concat cvx ift}.
/cond {{exit} concat cvx loop}.
% combinators
/dip {
[/.v /.q] let
.q /.v '
end}.
/apply {exec}.
/i {cvx exec}.
/linrec {
/.if ' /.then '
{.rec1
{/.if ' /.then ' /.rec1 ' /.rec2 ' linrec} i
.rec2}
ifte
end}.
/binrec {
[/.if /.then /.rec1 /.rec2] let
/.if ' /.then '
{ .rec1
{/.if ' /.then ' /.rec1 ' /.rec2 ' binrec} dip
{/.if ' /.then ' /.rec1 ' /.rec2 ' binrec} i
.rec2 }
ifte
end}.
/genrec {
[/.if /.then /.rec1 /.rec2] let
/.if ' /.then '
{.rec1
{/.if ' /.then ' /.rec1 ' /.rec2 ' genrec}
.rec2}
ifte
end}.
/tailrec {{} linrec}.
/primrec {
5 dict begin
/lzero? {
{list?} {empty?}
{zero?}
ifte}.
/lnext {
{list?} {rest}
{pred}
ifte}.
[/.param /.then /.rec] let*
{/.param ' lzero?} /.then '
{.param
{/.param ' lnext /.then ' /.rec ' primrec} i
.rec}
ifte
end}.
/cvstr {
4 dict begin
/elements exch def
/len elements length def
/str len string def
/i 0 def
{
i len ge { exit } if
str i
% The element of the array, as a hexadecimal string.
% If it exceeds 16#FF, this will fail with a rangecheck.
elements i get cvi
put
/i i 1 add def
} loop
str
end
} def
% debug
/puts {= (\n) print flush}.
/, {(=============\n)
% set the prompt to something else so that we know initlib is loaded.
/prompt {(>| ) print flush} bind def</syntaxhighlight>
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