Hopefully fix unicodes and indented pretty printing

src/PrettyPrinting.jl

@@ -1591,8 +1591,14 @@ function _write_line(io::IOCustom, str::AbstractString)
     spaceleft = c - ind - io.printed
   end
   #@show spaceleft
-  firstlen = min(spaceleft, length(str))
-  firststr = str[1:firstlen]
+  # maybe rewrite using https://docs.julialang.org/en/v1/stdlib/Unicode/#Unicode.graphemes
+  # once minimum supported version for package is Julia 1.9
+  normalised_str = Base.Unicode.normalize(str)
+  firstlen = min(spaceleft, length(normalised_str))
+  # make an iterator over valid indices
+  firstiter = Base.Iterators.take(eachindex(normalised_str), firstlen)
+  restiter = Base.Iterators.drop(eachindex(normalised_str), firstlen)
+  firststr = normalised_str[collect(firstiter)]
   if io.lowercasefirst
     written += write(io.io, lowercasefirst(firststr))
     io.lowercasefirst = false
@@ -1601,13 +1607,18 @@ function _write_line(io::IOCustom, str::AbstractString)
     io.lowercasefirst = false
   end
   io.printed += textwidth(firststr)
-  reststr = str[firstlen + 1:end]
+  reststr = normalised_str[collect(restiter)]
   it = Iterators.partition(1:textwidth(reststr), c - ind > 0 ? c - ind : c)
   for i in it
+    # partitions of the spillover text
     written += write(io.io, "\n")
     written += write_indent(io)
-    written += write(io.io, reststr[i])
-    io.printed = textwidth(reststr[i])
+    for j in Base.Iterators.drop(Base.Iterators.take(reststr,i[end]), i[begin]-1)
+      # j is reststr[i[begin]:i[end]], constructed via iterators
+      written += write(io.io, j)
+      io.printed = textwidth(j)
+    end
+    println()
   end
   return written
 end

test/PrettyPrinting-test.jl

@@ -415,6 +415,30 @@ let
                              "    test\n" *
                              "  test"
 
+  # Test unicode
+  io = IOBuffer()
+  io = AbstractAlgebra.pretty(io, force_newlines = true)
+  println(io, "testing unicode")
+  print(io, AbstractAlgebra.Indent(), "ŎŚĊĂŖ")
+  @test String(take!(io)) == "testing unicode\n" *
+                             "  ŎŚĊĂŖ"
+
+  # Test evil unicodes
+  io = IOBuffer()
+  io = AbstractAlgebra.pretty(io, force_newlines = true)
+  _, c = displaysize(io)
+  print(io, AbstractAlgebra.Indent())
+  ellipses = String([0xe2, 0x80, 0xa6])
+  wedge = String([0xe2, 0x88, 0xa7])
+  iacute = String([0xc3, 0xad])
+  str = wedge ^25 * ellipses^25 * iacute^50
+  print(io, "aa", str)
+  @test String(take!(io)) == "  aa∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧∧" *
+                             "…………………………………………………………………" *
+                             "íííííííííííííííííííííííííí\n" *
+                             "  íííííííííííííííííííííííí"
+
+
   # Test string longer than width
   io = IOBuffer()
   io = AbstractAlgebra.pretty(io, force_newlines = true)
@@ -431,6 +455,50 @@ let
                              "    aa" * "t"^(c - 6) * "\n" *
                              "    tttttt"
 
+  # Test unicode string longer than width
+  io = IOBuffer()
+  io = AbstractAlgebra.pretty(io, force_newlines = true)
+  _, c = displaysize(io)
+  print(io, AbstractAlgebra.Indent())
+  println(io, "Ŏ"^c)
+  println(io, "aa", "Ś"^c)
+  print(io, AbstractAlgebra.Indent())
+  print(io, "aa", "Ŗ"^c)
+  @test String(take!(io)) == "  " * "Ŏ"^(c-2) * "\n" *
+                             "  ŎŎ" * "\n" *
+                             "  aa" * "Ś"^(c-4) * "\n" *
+                             "  ŚŚŚŚ" * "\n" *
+                             "    aa" * "Ŗ"^(c-6) * "\n" *
+                             "    ŖŖŖŖŖŖ"
+
+  # Test evil unicode string much longer than width
+  io = IOBuffer()
+  io = AbstractAlgebra.pretty(io, force_newlines = true)
+  _, c = displaysize(io)
+  ellipses = String([0xe2, 0x80, 0xa6])
+  wedge = String([0xe2, 0x88, 0xa7])
+  iacute = String([0xc3, 0xad])
+  print(io, AbstractAlgebra.Indent())
+  println(io, "Ŏ"^c)
+  println(io, ellipses^c)
+  println(io, "aa", "Ś"^c)
+  println(io, "bb", wedge^c)
+  print(io, AbstractAlgebra.Indent())
+  println(io, "aa", "Ŗ"^c)
+  print(io, iacute^c)
+  @test String(take!(io)) == "  " * "Ŏ"^(c-2) * "\n" *
+                              "  ŎŎ" * "\n" *
+                              "  " * ellipses^(c-2) * "\n" *
+                              "  " * ellipses^2 * "\n" *
+                              "  aa" * "Ś"^(c-4) * "\n" *
+                              "  ŚŚŚŚ" * "\n" *
+                              "  bb" * wedge^(c-4) * "\n" *
+                              "  " * wedge^4 * "\n" *
+                              "    aa" * "Ŗ"^(c-6) * "\n" *
+                              "    ŖŖŖŖŖŖ" * "\n" *
+                              "    " * iacute^(c-4) * "\n" *
+                              "    " * iacute^4
+
   # Test too much indentation
   io = IOBuffer()
   io = AbstractAlgebra.pretty(io, force_newlines = true)