Simplify options parsing, (thanks dzaima)

arc.bqn

@@ -7,25 +7,22 @@
 
 opts←{
   a←•args
+  _optl_←{≠◶⟨𝔾,𝔽⊑⟩ (»a∊𝕩)/a}
+  _opt_←{ 𝔽_optl_𝔾 ⋈𝕩}
   {𝕤
     •Out "Usage: "∾•name∾" [OPTION]...
   --help,-h: Display this help message
   --levels,-l FILE: load levels from FILE 
   --chars,-c STRING: Characters to display for each game object, needs to have length 15
   --fchars,-f STRING: Characters to represent each game object in the levels file, needs to have length 15
-  --start,-s N: Start directly at level number N
-  "
+  --start,-s N: Start directly at level number N"
     •Exit 0
-  }⍟((∨´"-h"<⊸⍷a)∨(∨´"--help"<⊸⍷a)) @
+  }⍟∨´"-h"‿"--help"∊a
 
-  c⇐{0=≠𝕩?" λ$⊕⭍#/\-|+<>^v";⊑𝕩}(»(<"--chars")⊸⍷)⊸/a
-  f⇐{0=≠𝕩?" λ$⊕⭍#/\-|+<>^v";⊑𝕩}(»(<"--fchars")⊸⍷)⊸/a
-  chars⇐{0=≠𝕩?c;⊑𝕩}(»(<"-c")⊸⍷)⊸/a
-  fchars⇐{0=≠𝕩?f;⊑𝕩}(»(<"-f")⊸⍷)⊸/a
-  l←{0=≠𝕩?"levels";⊑𝕩}(»(<"--levels")⊸⍷)⊸/a
-  levels⇐{0=≠𝕩?l;⊑𝕩}(»(<"-l")⊸⍷)⊸/a
-  s⇐{0=≠𝕩?1;1⌈⊑𝕩}•BQN¨⎊{𝕊: •Out "Invalid starting level number" ⋄ •Exit 1}(»(<"-s")⊸⍷)⊸/a
-  n⇐{0=≠𝕩?s;1⌈⊑𝕩}•BQN¨⎊{𝕊: •Out "Invalid starting level number" ⋄ •Exit 1}(»(<"--start")⊸⍷)⊸/a
+  chars ⇐ ⊢_optl_" λ$⊕⭍#/\-|+<>^v" "-c"‿"--chars"
+  fchars⇐ ⊢_optl_" λ$⊕⭍#/\-|+<>^v" "-f"‿"--fchars"
+  levels⇐ ⊢_optl_"levels"          "-l"‿"--levels"
+  n⇐{1⌈•BQN⎊{𝕊: •Out "Invalid starting level number" ⋄ •Exit 1} 𝕩}_optl_ 1 "-s"‿"--start"
 }
 
 g←Game⎊{𝕊: •Out •CurrentError @ ⋄ •Exit 1} opts.n‿opts.levels‿opts.chars‿opts.fchars‿⟨ansi.defaultB,ansi.yellow,ansi.cyan,ansi.red⟩