feat: initial commit for uri parser

.github/workflows/test.yml

@@ -0,0 +1,23 @@
+name: test
+
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: erlef/setup-beam@v1
+        with:
+          otp-version: "27.1.2"
+          gleam-version: "1.12.0"
+          rebar3-version: "3"
+          # elixir-version: "1"
+      - run: gleam deps download
+      - run: gleam test
+      - run: gleam format --check src test

.gitignore

@@ -0,0 +1,4 @@
+*.beam
+*.ez
+/build
+erl_crash.dump

README.md

@@ -1,2 +1,27 @@
+
 # uri
+
 Uri (RFC 3986) library for Gleam
+
+[![Package Version](https://img.shields.io/hexpm/v/uri)](https://hex.pm/packages/uri)
+[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/uri/)
+
+```sh
+gleam add uri@1
+```
+```gleam
+import uri
+
+pub fn main() -> Nil {
+  // TODO: An example of the project in use
+}
+```
+
+Further documentation can be found at <https://hexdocs.pm/uri>.
+
+## Development
+
+```sh
+gleam run   # Run the project
+gleam test  # Run the tests
+```

gleam.toml

@@ -0,0 +1,20 @@
+name = "uri"
+version = "1.0.0"
+
+# Fill out these fields if you intend to generate HTML documentation or publish
+# your project to the Hex package manager.
+#
+# description = ""
+# licences = ["Apache-2.0"]
+# repository = { type = "github", user = "", repo = "" }
+# links = [{ title = "Website", href = "" }]
+#
+# For a full reference of all the available options, you can have a look at
+# https://gleam.run/writing-gleam/gleam-toml/.
+
+[dependencies]
+gleam_stdlib = ">= 0.44.0 and < 2.0.0"
+
+[dev-dependencies]
+gleeunit = ">= 1.0.0 and < 2.0.0"
+startest = ">= 0.7.0 and < 1.0.0"

manifest.toml

@@ -0,0 +1,32 @@
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "argv", version = "1.0.2", build_tools = ["gleam"], requirements = [], otp_app = "argv", source = "hex", outer_checksum = "BA1FF0929525DEBA1CE67256E5ADF77A7CDDFE729E3E3F57A5BDCAA031DED09D" },
+  { name = "bigben", version = "1.0.1", build_tools = ["gleam"], requirements = ["birl", "gleam_erlang", "gleam_otp", "gleam_stdlib"], otp_app = "bigben", source = "hex", outer_checksum = "190E489610A80D76C48BACC75EB8314BD184FF0220AB0F251ABE760B993B91BB" },
+  { name = "birl", version = "1.8.0", build_tools = ["gleam"], requirements = ["gleam_regexp", "gleam_stdlib", "ranger"], otp_app = "birl", source = "hex", outer_checksum = "2AC7BA26F998E3DFADDB657148BD5DDFE966958AD4D6D6957DD0D22E5B56C400" },
+  { name = "exception", version = "2.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "exception", source = "hex", outer_checksum = "329D269D5C2A314F7364BD2711372B6F2C58FA6F39981572E5CA68624D291F8C" },
+  { name = "filepath", version = "1.1.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "B06A9AF0BF10E51401D64B98E4B627F1D2E48C154967DA7AF4D0914780A6D40A" },
+  { name = "gleam_community_ansi", version = "1.4.3", build_tools = ["gleam"], requirements = ["gleam_community_colour", "gleam_regexp", "gleam_stdlib"], otp_app = "gleam_community_ansi", source = "hex", outer_checksum = "8A62AE9CC6EA65BEA630D95016D6C07E4F9973565FA3D0DE68DC4200D8E0DD27" },
+  { name = "gleam_community_colour", version = "2.0.2", build_tools = ["gleam"], requirements = ["gleam_json", "gleam_stdlib"], otp_app = "gleam_community_colour", source = "hex", outer_checksum = "E34DD2C896AC3792151EDA939DA435FF3B69922F33415ED3C4406C932FBE9634" },
+  { name = "gleam_erlang", version = "1.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "1124AD3AA21143E5AF0FC5CF3D9529F6DB8CA03E43A55711B60B6B7B3874375C" },
+  { name = "gleam_javascript", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_javascript", source = "hex", outer_checksum = "EF6C77A506F026C6FB37941889477CD5E4234FCD4337FF0E9384E297CB8F97EB" },
+  { name = "gleam_json", version = "3.0.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_json", source = "hex", outer_checksum = "874FA3C3BB6E22DD2BB111966BD40B3759E9094E05257899A7C08F5DE77EC049" },
+  { name = "gleam_otp", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "7987CBEBC8060B88F14575DEF546253F3116EBE2A5DA6FD82F38243FCE97C54B" },
+  { name = "gleam_regexp", version = "1.1.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_regexp", source = "hex", outer_checksum = "9C215C6CA84A5B35BB934A9B61A9A306EC743153BE2B0425A0D032E477B062A9" },
+  { name = "gleam_stdlib", version = "0.62.1", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "0080706D3A5A9A36C40C68481D1D231D243AF602E6D2A2BE67BA8F8F4DFF45EC" },
+  { name = "gleam_time", version = "1.4.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_time", source = "hex", outer_checksum = "DCDDC040CE97DA3D2A925CDBBA08D8A78681139745754A83998641C8A3F6587E" },
+  { name = "gleam_yielder", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_yielder", source = "hex", outer_checksum = "8E4E4ECFA7982859F430C57F549200C7749823C106759F4A19A78AEA6687717A" },
+  { name = "gleeunit", version = "1.6.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "FDC68A8C492B1E9B429249062CD9BAC9B5538C6FBF584817205D0998C42E1DAC" },
+  { name = "glint", version = "1.2.1", build_tools = ["gleam"], requirements = ["gleam_community_ansi", "gleam_community_colour", "gleam_stdlib", "snag"], otp_app = "glint", source = "hex", outer_checksum = "2214C7CEFDE457CEE62140C3D4899B964E05236DA74E4243DFADF4AF29C382BB" },
+  { name = "ranger", version = "1.4.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_yielder"], otp_app = "ranger", source = "hex", outer_checksum = "C8988E8F8CDBD3E7F4D8F2E663EF76490390899C2B2885A6432E942495B3E854" },
+  { name = "simplifile", version = "2.3.0", build_tools = ["gleam"], requirements = ["filepath", "gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "0A868DAC6063D9E983477981839810DC2E553285AB4588B87E3E9C96A7FB4CB4" },
+  { name = "snag", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "snag", source = "hex", outer_checksum = "7E9F06390040EB5FAB392CE642771484136F2EC103A92AE11BA898C8167E6E17" },
+  { name = "startest", version = "0.7.0", build_tools = ["gleam"], requirements = ["argv", "bigben", "birl", "exception", "gleam_community_ansi", "gleam_erlang", "gleam_javascript", "gleam_regexp", "gleam_stdlib", "glint", "simplifile", "tom"], otp_app = "startest", source = "hex", outer_checksum = "71B9CB82C4B8779A4BD54C7151DF7D0B0F778D0DDE805B782B44EFA7BA8F50DA" },
+  { name = "tom", version = "2.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "gleam_time"], otp_app = "tom", source = "hex", outer_checksum = "74D0C5A3761F7A7D06994755D4D5AD854122EF8E9F9F76A3E7547606D8C77091" },
+]
+
+[requirements]
+gleam_stdlib = { version = ">= 0.44.0 and < 2.0.0" }
+gleeunit = { version = ">= 1.0.0 and < 2.0.0" }
+startest = { version = ">= 0.7.0 and < 1.0.0" }

src/uri.gleam

@@ -0,0 +1,733 @@
+import gleam/bool
+import gleam/int
+import gleam/list.{Continue, Stop}
+import gleam/option.{type Option, None, Some}
+import gleam/result
+import gleam/string
+import gleam/uri
+
+pub type Uri {
+  Uri(
+    scheme: Option(String),
+    userinfo: Option(String),
+    host: Option(String),
+    port: Option(Int),
+    path: String,
+    query: Option(String),
+    fragment: Option(String),
+  )
+}
+
+pub const empty_uri = Uri(None, None, None, None, "", None, None)
+
+pub fn main() {
+  // parse("test://asd@test!te%20ste/a/b/c?a=31#asd") |> echo
+  // parse("test:/blah") |> echo
+  parse("foo://user:password@localhost") |> echo
+  uri.parse("foo://user:password@localhost") |> echo
+  // uri.parse("../../") |> echo
+}
+
+pub fn parse(uri: String) -> Result(Uri, Nil) {
+  case parse_scheme(uri) {
+    Ok(#(scheme, rest)) -> {
+      use #(rel_part, rest) <- result.try(parse_hier_part(rest))
+
+      use #(query, rest) <- result.try(parse_query(rest))
+
+      use #(fragment, rest) <- result.try(parse_fragment(rest))
+
+      case rest {
+        "" -> Ok(combine_uris([scheme, rel_part, query, fragment]))
+        _ -> Error(Nil)
+      }
+    }
+    Error(_) -> {
+      use #(rel_part, rest) <- result.try(parse_relative_part(uri))
+
+      use #(query, rest) <- result.try(parse_query(rest))
+
+      use #(fragment, rest) <- result.try(parse_fragment(rest))
+
+      case rest {
+        "" -> Ok(combine_uris([rel_part, query, fragment]))
+        _ -> Error(Nil)
+      }
+    }
+  }
+}
+
+fn parse_query(str: String) -> Result(#(Uri, String), Nil) {
+  case str {
+    "?" <> rest -> {
+      let #(query, rest) = get_multiple_optional(parse_query_fragment, rest)
+      Ok(#(Uri(..empty_uri, query: Some(query)), rest))
+    }
+    _ -> Ok(#(empty_uri, str))
+  }
+}
+
+fn parse_fragment(str: String) -> Result(#(Uri, String), Nil) {
+  case str {
+    "#" <> rest -> {
+      let #(fragment, rest) = get_multiple_optional(parse_query_fragment, rest)
+      Ok(#(Uri(..empty_uri, fragment: Some(fragment)), rest))
+    }
+    _ -> Ok(#(empty_uri, str))
+  }
+}
+
+fn parse_hier_part(str: String) -> Result(#(Uri, String), Nil) {
+  list.fold_until(
+    [parse_authority, parse_absolute, parse_rootless, parse_empty],
+    Error(Nil),
+    get_parser_fn(str),
+  )
+}
+
+fn parse_relative_part(str: String) -> Result(#(Uri, String), Nil) {
+  list.fold_until(
+    [parse_authority, parse_absolute, parse_noscheme, parse_empty],
+    Error(Nil),
+    get_parser_fn(str),
+  )
+}
+
+fn parse_absolute(str: String) -> Result(#(Uri, String), Nil) {
+  case str {
+    "/" <> rest -> {
+      use #(seg1, rest) <- result.try(do_parse_segment_nz(rest))
+
+      let #(segs, rest) =
+        get_multiple_optional(
+          fn(str) {
+            case str {
+              "/" <> rest -> {
+                do_parse_segment(rest, do_parse_pchar, "/")
+              }
+              _ -> Error(Nil)
+            }
+          },
+          rest,
+        )
+
+      Ok(#(Uri(None, None, None, None, "/" <> seg1 <> segs, None, None), rest))
+    }
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_rootless(str: String) -> Result(#(Uri, String), Nil) {
+  use #(seg1, rest) <- result.try(do_parse_segment_nz(str))
+
+  let #(segs, rest) =
+    get_multiple_optional(
+      fn(str) {
+        case str {
+          "/" <> rest -> {
+            do_parse_segment(rest, do_parse_pchar, "/")
+          }
+          _ -> Error(Nil)
+        }
+      },
+      rest,
+    )
+
+  Ok(#(Uri(None, None, None, None, seg1 <> segs, None, None), rest))
+}
+
+fn parse_noscheme(str: String) -> Result(#(Uri, String), Nil) {
+  use #(seg1, rest) <- result.try(do_parse_segment_nz_nc(str))
+
+  let #(segs, rest) =
+    get_multiple_optional(
+      fn(str) {
+        case str {
+          "/" <> rest -> {
+            do_parse_segment(rest, do_parse_pchar, "/")
+          }
+          _ -> Error(Nil)
+        }
+      },
+      rest,
+    )
+
+  Ok(#(Uri(None, None, None, None, seg1 <> segs, None, None), rest))
+}
+
+fn get_multiple_optional(opt_fn, str: String) {
+  case get_multiple(opt_fn, str) {
+    Error(_) -> #("", str)
+    Ok(r) -> r
+  }
+}
+
+fn parse_empty(str: String) -> Result(#(Uri, String), Nil) {
+  Ok(#(Uri(None, None, None, None, "", None, None), str))
+}
+
+fn parse_authority(str: String) -> Result(#(Uri, String), Nil) {
+  case str {
+    "//" <> rest -> {
+      parse_authority_part(rest)
+    }
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_authority_part(str: String) -> Result(#(Uri, String), Nil) {
+  let #(ui, rest) = case parse_userinfo(str, "") {
+    Ok(#(ui, rest)) -> #(Some(ui), rest)
+    Error(_) -> #(None, str)
+  }
+
+  use #(host, rest) <- result.try(parse_host(rest))
+
+  let #(port, rest) = case parse_port(rest) {
+    Ok(#("", rest)) -> #(None, rest)
+    Error(_) -> #(None, rest)
+    Ok(#(port, rest)) -> {
+      let assert Ok(port) = int.parse(port)
+      #(Some(port), rest)
+    }
+  }
+
+  let #(path, rest) = parse_abs_empty(rest)
+
+  Ok(#(Uri(None, ui, Some(host), port, path, None, None), rest))
+}
+
+fn parse_port(str: String) {
+  case str {
+    ":" <> rest -> {
+      Ok(parse_digits(rest, ""))
+    }
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_digits(str: String, digits: String) {
+  case parse_digit(str) {
+    Ok(#(d, rest)) -> {
+      parse_digits(rest, digits <> d)
+    }
+    Error(_) -> #(digits, str)
+  }
+}
+
+fn parse_host(str: String) {
+  list.fold_until(
+    [parse_ip_literal, parse_ipv4, parse_reg_name],
+    Error(Nil),
+    get_parser_fn(str),
+  )
+}
+
+fn parse_ip_literal(str: String) {
+  Error(Nil)
+}
+
+fn get_multiple(
+  to_run: fn(String) -> Result(#(String, String), Nil),
+  str: String,
+) -> Result(#(String, String), Nil) {
+  case do_get_multiple(to_run, str, "") {
+    Ok(#("", _)) | Error(Nil) -> Error(Nil)
+    Ok(#(r, rest)) -> Ok(#(r, rest))
+  }
+}
+
+fn do_get_multiple(
+  to_run: fn(String) -> Result(#(String, String), Nil),
+  str: String,
+  ret: String,
+) -> Result(#(String, String), Nil) {
+  case str {
+    "" -> Ok(#(ret, str))
+    _ ->
+      case to_run(str) {
+        Ok(#(r, rest)) -> do_get_multiple(to_run, rest, ret <> r)
+        Error(_) -> Ok(#(ret, str))
+      }
+  }
+}
+
+fn parse_query_fragment(str: String) {
+  list.fold_until(
+    [
+      do_parse_pchar,
+      fn(str: String) {
+        case str {
+          "/" as l <> rest | "?" as l <> rest -> Ok(#(l, rest))
+          _ -> Error(Nil)
+        }
+      },
+    ],
+    Error(Nil),
+    get_parser_fn(str),
+  )
+}
+
+fn parse_abs_empty(str: String) -> #(String, String) {
+  get_multiple_optional(
+    fn(str) {
+      case str {
+        "/" <> rest -> {
+          do_parse_segment(rest, do_parse_pchar, "/")
+        }
+        _ -> Error(Nil)
+      }
+    },
+    str,
+  )
+}
+
+fn do_parse_segment(
+  str: String,
+  char_fn,
+  segment: String,
+) -> Result(#(String, String), Nil) {
+  case char_fn(str) {
+    Error(Nil) | Ok(#("", _)) -> Ok(#(segment, str))
+    Ok(#(l, rest)) -> do_parse_segment(rest, char_fn, segment <> l)
+  }
+}
+
+fn do_parse_segment_nz(str: String) {
+  use #(char1, rest) <- result.try(do_parse_pchar(str))
+
+  use #(chars, rest) <- result.try(do_parse_segment(rest, do_parse_pchar, char1))
+
+  Ok(#(chars, rest))
+}
+
+fn do_parse_segment_nz_nc(str: String) {
+  use #(char1, rest) <- result.try(do_parse_pchar_nc(str))
+
+  use #(chars, rest) <- result.try(do_parse_segment(
+    rest,
+    do_parse_pchar_nc,
+    char1,
+  ))
+
+  Ok(#(chars, rest))
+}
+
+fn do_parse_pchar(str: String) {
+  list.fold_until(
+    [
+      parse_unreserved,
+      parse_pct_encoded,
+      parse_sub_delim,
+      fn(str: String) {
+        case str {
+          ":" as l <> rest | "@" as l <> rest -> Ok(#(l, rest))
+          _ -> Error(Nil)
+        }
+      },
+    ],
+    Error(Nil),
+    get_parser_fn(str),
+  )
+}
+
+fn do_parse_pchar_nc(str: String) {
+  list.fold_until(
+    [
+      parse_unreserved,
+      parse_pct_encoded,
+      parse_sub_delim,
+      fn(str: String) {
+        case str {
+          "@" as l <> rest -> Ok(#(l, rest))
+          _ -> Error(Nil)
+        }
+      },
+    ],
+    Error(Nil),
+    get_parser_fn(str),
+  )
+}
+
+fn parse_reg_name(str: String) {
+  // can't error
+
+  case do_parse_reg_name(str, "") {
+    Error(Nil) -> Ok(#("", str))
+    Ok(#(reg_name, rest)) -> Ok(#(reg_name, rest))
+  }
+}
+
+fn do_parse_reg_name(str: String, reg_name: String) {
+  case
+    list.fold_until(
+      [parse_unreserved, parse_pct_encoded, parse_sub_delim],
+      Error(Nil),
+      get_parser_fn(str),
+    )
+  {
+    Error(Nil) | Ok(#("", _)) -> Ok(#(reg_name, str))
+    Ok(#(l, rest)) -> do_parse_reg_name(rest, reg_name <> l)
+  }
+}
+
+fn parse_pct_encoded(str: String) {
+  case str {
+    "%" <> rest -> {
+      use #(hex1, rest) <- result.try(parse_hex_digit(rest))
+      use #(hex2, rest) <- result.try(parse_hex_digit(rest))
+
+      Ok(#("%" <> hex1 <> hex2, rest))
+    }
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_sub_delim(str: String) {
+  case str {
+    "!" as l <> rest
+    | "$" as l <> rest
+    | "&" as l <> rest
+    | "'" as l <> rest
+    | "(" as l <> rest
+    | ")" as l <> rest
+    | "*" as l <> rest
+    | "+" as l <> rest
+    | "," as l <> rest
+    | ";" as l <> rest
+    | "=" as l <> rest -> Ok(#(l, rest))
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_ipv4(str: String) {
+  use #(oct1, rest) <- result.try(parse_dec_octet(str))
+  use rest <- result.try(case rest {
+    "." <> rest -> Ok(rest)
+    _ -> Error(Nil)
+  })
+  use #(oct2, rest) <- result.try(parse_dec_octet(rest))
+  use rest <- result.try(case rest {
+    "." <> rest -> Ok(rest)
+    _ -> Error(Nil)
+  })
+  use #(oct3, rest) <- result.try(parse_dec_octet(rest))
+  use rest <- result.try(case rest {
+    "." <> rest -> Ok(rest)
+    _ -> Error(Nil)
+  })
+  use #(oct4, rest) <- result.try(parse_dec_octet(rest))
+  Ok(#(oct1 <> "." <> oct2 <> "." <> oct3 <> "." <> oct4, rest))
+}
+
+fn parse_dec_octet(str: String) -> Result(#(String, String), Nil) {
+  let matches = [
+    ["2", "5", "012345"],
+    ["2", "01234", "0123456789"],
+    ["1", "0123456789", "0123456789"],
+    ["123456789", "0123456789"],
+    ["0123456789"],
+  ]
+
+  list.fold_until(matches, Error(Nil), fn(_, chars) {
+    case
+      list.fold_until(chars, #("", str), fn(acc, charset) {
+        let #(octet, str) = acc
+        case string.pop_grapheme(str) {
+          Error(_) -> Stop(#("", ""))
+          Ok(#(char, rest)) -> {
+            case string.contains(charset, char) {
+              True -> Continue(#(octet <> char, rest))
+              False -> Stop(#("", ""))
+            }
+          }
+        }
+      })
+    {
+      #("", _) -> Continue(Error(Nil))
+      #(octet, rest) -> Stop(Ok(#(octet, rest)))
+    }
+  })
+}
+
+fn parse_userinfo(
+  str: String,
+  userinfo: String,
+) -> Result(#(String, String), Nil) {
+  case str {
+    "@" <> rest -> Ok(#(userinfo, rest))
+    "" -> Error(Nil)
+    _ -> {
+      use #(part, rest) <- result.try(list.fold_until(
+        [
+          parse_unreserved,
+          parse_pct_encoded,
+          parse_sub_delim,
+          fn(str: String) {
+            case str {
+              ":" as l <> rest -> Ok(#(l, rest))
+              _ -> Error(Nil)
+            }
+          },
+        ],
+        Error(Nil),
+        get_parser_fn(str),
+      ))
+      parse_userinfo(rest, userinfo <> part)
+    }
+  }
+}
+
+fn parse_scheme(str: String) -> Result(#(Uri, String), Nil) {
+  case parse_alpha(str) {
+    Ok(#(first, rest)) -> {
+      case do_parse_scheme(rest, first) {
+        Error(_) -> Error(Nil)
+        Ok(#(scheme, rest)) ->
+          Ok(#(Uri(Some(scheme), None, None, None, "", None, None), rest))
+      }
+    }
+    _ -> Error(Nil)
+  }
+}
+
+fn do_parse_scheme(
+  str: String,
+  scheme: String,
+) -> Result(#(String, String), Nil) {
+  case str {
+    ":" <> rest -> Ok(#(scheme, rest))
+    "" -> Error(Nil)
+    _ -> {
+      use #(part, rest) <- result.try(list.fold_until(
+        [
+          parse_alpha,
+          parse_digit,
+          fn(str) {
+            case str {
+              "+" as l <> rest | "-" as l <> rest | "." as l <> rest ->
+                Ok(#(l, rest))
+              _ -> Error(Nil)
+            }
+          },
+        ],
+        Error(Nil),
+        get_parser_fn(str),
+      ))
+      do_parse_scheme(rest, scheme <> part)
+    }
+  }
+}
+
+fn get_parser_fn(
+  str: String,
+) -> fn(a, fn(String) -> Result(b, c)) -> list.ContinueOrStop(Result(b, Nil)) {
+  fn(_, parse_fn) {
+    case parse_fn(str) {
+      Ok(r) -> Stop(Ok(r))
+      Error(_) -> Continue(Error(Nil))
+    }
+  }
+}
+
+fn parse_hex_digits(str, min, max) {
+  use <- bool.guard(when: min < 0 || max <= 0 || min > max, return: Error(Nil))
+  case
+    list.repeat("", max)
+    |> list.fold_until(Ok(#("", str, 0)), fn(acc, _) {
+      let assert Ok(#(hex, str, i)) = acc
+      case parse_hex_digit(str) {
+        Error(_) ->
+          case i < min {
+            True -> Stop(Error(Nil))
+            False -> Stop(Ok(#(hex, str, i)))
+          }
+        Ok(#(l, rest)) -> Continue(Ok(#(hex <> l, rest, i + 1)))
+      }
+    })
+  {
+    Error(_) -> Error(Nil)
+    Ok(#(hex, str, _)) -> Ok(#(hex, str))
+  }
+}
+
+fn parse_hex_digit(str) {
+  case str {
+    "0" as l <> rest
+    | "1" as l <> rest
+    | "2" as l <> rest
+    | "3" as l <> rest
+    | "4" as l <> rest
+    | "5" as l <> rest
+    | "6" as l <> rest
+    | "7" as l <> rest
+    | "8" as l <> rest
+    | "9" as l <> rest
+    | "a" as l <> rest
+    | "b" as l <> rest
+    | "c" as l <> rest
+    | "d" as l <> rest
+    | "e" as l <> rest
+    | "f" as l <> rest
+    | "A" as l <> rest
+    | "B" as l <> rest
+    | "C" as l <> rest
+    | "D" as l <> rest
+    | "E" as l <> rest
+    | "F" as l <> rest -> Ok(#(l, rest))
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_digit(str: String) -> Result(#(String, String), Nil) {
+  case str {
+    "0" as l <> rest
+    | "1" as l <> rest
+    | "2" as l <> rest
+    | "3" as l <> rest
+    | "4" as l <> rest
+    | "5" as l <> rest
+    | "6" as l <> rest
+    | "7" as l <> rest
+    | "8" as l <> rest
+    | "9" as l <> rest -> Ok(#(l, rest))
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_alpha(str: String) -> Result(#(String, String), Nil) {
+  case str {
+    "a" as l <> rest
+    | "b" as l <> rest
+    | "c" as l <> rest
+    | "d" as l <> rest
+    | "e" as l <> rest
+    | "f" as l <> rest
+    | "g" as l <> rest
+    | "h" as l <> rest
+    | "i" as l <> rest
+    | "j" as l <> rest
+    | "k" as l <> rest
+    | "l" as l <> rest
+    | "m" as l <> rest
+    | "n" as l <> rest
+    | "o" as l <> rest
+    | "p" as l <> rest
+    | "q" as l <> rest
+    | "r" as l <> rest
+    | "s" as l <> rest
+    | "t" as l <> rest
+    | "u" as l <> rest
+    | "v" as l <> rest
+    | "w" as l <> rest
+    | "x" as l <> rest
+    | "y" as l <> rest
+    | "z" as l <> rest
+    | "A" as l <> rest
+    | "B" as l <> rest
+    | "C" as l <> rest
+    | "D" as l <> rest
+    | "E" as l <> rest
+    | "F" as l <> rest
+    | "G" as l <> rest
+    | "H" as l <> rest
+    | "I" as l <> rest
+    | "J" as l <> rest
+    | "K" as l <> rest
+    | "L" as l <> rest
+    | "M" as l <> rest
+    | "N" as l <> rest
+    | "O" as l <> rest
+    | "P" as l <> rest
+    | "Q" as l <> rest
+    | "R" as l <> rest
+    | "S" as l <> rest
+    | "T" as l <> rest
+    | "U" as l <> rest
+    | "V" as l <> rest
+    | "W" as l <> rest
+    | "X" as l <> rest
+    | "Y" as l <> rest
+    | "Z" as l <> rest -> Ok(#(l, rest))
+    _ -> Error(Nil)
+  }
+}
+
+fn parse_unreserved(str: String) -> Result(#(String, String), Nil) {
+  list.fold_until(
+    [
+      parse_alpha,
+      parse_digit,
+      fn(str) {
+        case str {
+          "_" as l <> rest
+          | "-" as l <> rest
+          | "." as l <> rest
+          | "~" as l <> rest -> Ok(#(l, rest))
+          _ -> Error(Nil)
+        }
+      },
+    ],
+    Error(Nil),
+    get_parser_fn(str),
+  )
+}
+
+fn combine_uris(uris: List(Uri)) -> Uri {
+  list.fold(uris, Uri(None, None, None, None, "", None, None), fn(acc, uri) {
+    let acc = case uri {
+      Uri(Some(scheme), _, _, _, _, _, _) -> Uri(..acc, scheme: Some(scheme))
+      _ -> acc
+    }
+    let acc = case uri {
+      Uri(_, Some(userinfo), _, _, _, _, _) ->
+        Uri(..acc, userinfo: Some(userinfo))
+      _ -> acc
+    }
+    let acc = case uri {
+      Uri(_, _, Some(host), _, _, _, _) -> Uri(..acc, host: Some(host))
+      _ -> acc
+    }
+    let acc = case uri {
+      Uri(_, _, _, Some(port), _, _, _) -> Uri(..acc, port: Some(port))
+      _ -> acc
+    }
+    let acc = case uri {
+      Uri(_, _, _, _, path, _, _) if path != "" -> Uri(..acc, path: path)
+      _ -> acc
+    }
+    let acc = case uri {
+      Uri(_, _, _, _, _, Some(query), _) -> Uri(..acc, query: Some(query))
+      _ -> acc
+    }
+    case uri {
+      Uri(_, _, _, _, _, _, Some(fragment)) ->
+        Uri(..acc, fragment: Some(fragment))
+      _ -> acc
+    }
+  })
+}
+
+pub fn to_uri(uri: Uri) -> uri.Uri {
+  uri.Uri(
+    uri.scheme,
+    uri.userinfo,
+    uri.host,
+    uri.port,
+    uri.path,
+    uri.query,
+    uri.fragment,
+  )
+}
+
+pub fn from_uri(uri: uri.Uri) -> Uri {
+  Uri(
+    uri.scheme,
+    uri.userinfo,
+    uri.host,
+    uri.port,
+    uri.path,
+    uri.query,
+    uri.fragment,
+  )
+}

test/uri_test.gleam

@@ -0,0 +1,103 @@
+import gleam/option.{Some}
+import gleeunit/should
+import startest.{describe, it}
+import uri.{Uri}
+
+pub fn main() {
+  startest.run(startest.default_config())
+}
+
+pub fn parse_scheme_tests() {
+  describe("scheme parsing", [
+    it("should parse", fn() {
+      uri.parse("") |> should.equal(Ok(uri.empty_uri))
+      uri.parse("foo")
+      |> should.equal(Ok(Uri(..uri.empty_uri, path: "foo")))
+      uri.parse("foo:")
+      |> should.equal(Ok(Uri(..uri.empty_uri, scheme: Some("foo"))))
+      uri.parse("foo:bar:nisse")
+      |> should.equal(Ok(
+        Uri(..uri.empty_uri, scheme: Some("foo"), path: "bar:nisse"),
+      ))
+      uri.parse("foo://")
+      |> should.equal(Ok(
+        Uri(..uri.empty_uri, scheme: Some("foo"), host: Some("")),
+      ))
+      uri.parse("foo:///")
+      |> should.equal(Ok(
+        Uri(..uri.empty_uri, scheme: Some("foo"), host: Some(""), path: "/"),
+      ))
+      uri.parse("foo:////")
+      |> should.equal(Ok(
+        Uri(..uri.empty_uri, scheme: Some("foo"), host: Some(""), path: "//"),
+      ))
+    }),
+  ])
+}
+
+pub fn parse_userinfo_tests() {
+  describe("userinfo parsing", [
+    it("should parse", fn() {
+      uri.parse("user:password@localhost")
+      |> should.equal(Ok(
+        Uri(..uri.empty_uri, scheme: Some("user"), path: "password@localhost"),
+      ))
+      uri.parse("user@")
+      |> should.equal(Ok(Uri(..uri.empty_uri, path: "user@")))
+      uri.parse("/user@")
+      |> should.equal(Ok(Uri(..uri.empty_uri, path: "/user@")))
+      uri.parse("user@localhost")
+      |> should.equal(Ok(Uri(..uri.empty_uri, path: "user@localhost")))
+      uri.parse("//user@localhost")
+      |> should.equal(Ok(
+        Uri(..uri.empty_uri, userinfo: Some("user"), host: Some("localhost")),
+      ))
+      uri.parse("//user:password@localhost")
+      |> should.equal(Ok(
+        Uri(
+          ..uri.empty_uri,
+          userinfo: Some("user:password"),
+          host: Some("localhost"),
+        ),
+      ))
+      uri.parse("foo:/user@")
+      |> should.equal(Ok(
+        Uri(..uri.empty_uri, scheme: Some("foo"), path: "/user@"),
+      ))
+      uri.parse("foo://user@localhost")
+      |> should.equal(Ok(
+        Uri(
+          ..uri.empty_uri,
+          scheme: Some("foo"),
+          userinfo: Some("user"),
+          host: Some("localhost"),
+        ),
+      ))
+      uri.parse("foo://user:password@localhost")
+      |> should.equal(Ok(
+        Uri(
+          ..uri.empty_uri,
+          scheme: Some("foo"),
+          userinfo: Some("user:password"),
+          host: Some("localhost"),
+        ),
+      ))
+    }),
+  ])
+}
+// gleeunit test functions end in `_test`
+// pub fn uri_test() {
+//   match("uri:")
+//   match("//@")
+//   match("//")
+//   match("")
+//   match("?")
+//   match("#")
+//   match("#\t")
+//   match("//:")
+// }
+
+// fn match(uri: String) {
+//   assert uri.parse(uri)  |> uri.to_uri
+//     == uri2.parse(uri)
+// }