Param.check.letter: def of bolt@1.27.0.0
Import: import bolt@1.27.0.0/src/rules/style/param.bend as Param
Lines 14-20 of bolt@1.27.0.0/src/rules/style/param.bend: https://jend.leeeet.dev/read.txt?path=bolt@1.27.0.0/src/rules/style/param.bend&start_line=14&end_line=20

import Base

# one character, and a capital: a type parameter
def check.letter(cs: List<&2, Char>) -> Bool:
  match cs:
    case Con{c, Nil{}}:
      Char.is_upper(c)
    case other:
      False{}

Uses (4):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Char
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Char.is_upper
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List