WIP draft of squeaky-clean concept exercise

config.json

@@ -57,6 +57,16 @@
           "basics"
         ],
         "status": "wip"
+      },
+      {
+        "slug": "squeaky-clean",
+        "name": "squeaky-clean",
+        "uuid": "7c06c4e8-4bc1-42c3-982a-f973f45193bf",
+        "concepts": [
+          "chars"
+        ],
+        "prerequisites": [],
+        "status": "wip"
       }
     ],
     "practice": [

exercises/concept/squeaky-clean/.docs/hints.md

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+# Hints
+
+## 1. Replace any spaces encountered with underscores
+
+- [Reference documentation][char-docs] for `Char`s is here.
+- `Char` literals are enclosed in 'single quotes', `String` literals in "double quotes".
+
+## 2. Remove all whitespace
+
+- See [this method][isspace] for detecting whitespace characters and [this method][isdigit] for digits.
+
+## 3. Convert camel-case to kebab-case
+
+- See [this method][isuppercase] to check if a character is case.
+- See [this method][lowercase] to convert a character to lower case.
+
+## 5. Omit Greek lower case letters
+
+- `Char`s support the default equality and comparison operators.
+
+## 6. Combine these operations to operate on a string
+
+- A string can be iterated over, in the same way as an array.
+- To do all the transforms, consider using a comprehension.
+- Multiple strings can be [joined][join] into one.
+
+[char-docs]: https://docs.julialang.org/en/v1/manual/strings/#man-characters
+[isspace]: https://docs.julialang.org/en/v1/base/strings/#Base.Unicode.isspace
+[isdigit]: https://docs.julialang.org/en/v1/base/strings/#Base.Unicode.isdigit
+[lowercase]: https://docs.julialang.org/en/v1/base/strings/#Base.Unicode.lowercase
+[isuppercase]: https://docs.julialang.org/en/v1/base/strings/#Base.Unicode.isuppercase
+[join]: https://docs.julialang.org/en/v1/base/strings/#Base.join

exercises/concept/squeaky-clean/.docs/instructions.md

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+# Instructions
+
+In this exercise you will implement a partial set of utility routines to help a developer clean up identifier names.
+
+In the 6 tasks you will gradually build up the functions `transform` to convert single characters and `clean` to convert strings.
+
+A valid identifier comprises zero or more letters, underscores, hyphens, question marks and emojis.
+
+If an empty string is passed to the `clean` function, an empty string should be returned.
+
+## 1. Replace any hyphens encountered with underscores
+
+Implement the `transform` function to replace any hyphens with underscores.
+
+```julia
+transform('-')  # => "_"
+```
+
+## 2. Remove all whitespace
+
+Remove all whitespace characters.
+This will include leading and trailing whitespace.
+
+```julia
+transform(' ')  # => ""
+```
+
+## 3. Convert camelCase to kebab-case
+
+Modify the `transform` function to convert camelCase to kebab-case
+
+```julia
+transform('D')  # => "-d"
+```
+
+## 4. Omit characters that are digits
+
+Modify the `transform` function to omit any characters that are numeric.
+
+```julia
+transform('7')  # => ""
+```
+
+## 5. Replace Greek lower case letters with question marks
+
+Modify the `transform` function to replace any Greek letters in the range 'α' to 'ω'.
+
+```julia
+transform('β') # => "?"
+```
+
+## 6. Combine these operations to operate on a string
+
+Implement the `clean` function to apply these operations to an entire string.
+
+Characters which fall outside the rules should pass through unchanged.
+
+```julia
+clean("  a2b Cd-ω😀  ") #  => "ab-cd_?😀"
+```

exercises/concept/squeaky-clean/.docs/introduction.md

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+# Introduction
+
+_Left blank for now. Contents of `concepts/chars/introduction.md` to be copied here when finalized._

exercises/concept/squeaky-clean/.meta/config.json

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+{
+  "authors": [
+    "colinleach"
+  ],
+  "files": {
+    "solution": [
+      "squeaky-clean.jl"
+    ],
+    "test": [
+      "runtests.jl"
+    ],
+    "exemplar": [
+      ".meta/exemplar.jl"
+    ]
+  },
+  "forked_from": [
+    "fsharp/squeaky-clean"
+  ],
+  "blurb": "Learn about characters by cleaning strings."
+}

exercises/concept/squeaky-clean/.meta/exemplar.jl

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+function transform(ch)
+    if ch == '-'
+        "_"
+    elseif 'α' ≤ ch ≤ 'ω' 
+        "?"
+    elseif isspace(ch) || isdigit(ch)
+        ""
+    elseif isuppercase(ch)
+        "-$(lowercase(ch))"
+    else
+        string(ch)
+    end
+end
+
+# The default delimiter is "", so it is only included below for documentation
+clean(str) = join([transform(ch) for ch in str], "")

exercises/concept/squeaky-clean/runtests.jl

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+using Test
+
+include("squeaky-clean.jl")
+
+@testset verbose = true "tests" begin
+    @testset "1. Hyphens" begin
+        @test transform('a') == "a"
+        @test transform('-') == "_"
+    end
+
+    @testset "2. Whitespace" begin
+        @test transform(' ') == ""
+    end
+
+    @testset "3. camelCase" begin
+        @test transform('Γ') == "-γ"
+    end
+
+    @testset "4. digits" begin
+        @test transform('4') == ""
+    end
+
+    @testset "5. Greek lowercase" begin
+        @test transform('ω') == "?"
+    end
+
+    @testset "6. Combine in string" begin
+        @test clean("") == ""
+        @test clean("àḃç") == "àḃç"
+        @test clean("my   id") == "myid"
+        @test clean("   my   id  ") == "myid"
+        @test clean("9 cAbcĐ😀ω") == "c-abc-đ😀?"
+    end
+end

exercises/concept/squeaky-clean/squeaky-clean.jl

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+function transform(ch)
+
+end
+
+function clean(str)
+
+end