Add a starting point for glob API.

src/Glob.elm

@@ -0,0 +1,89 @@
+module Glob exposing (..)
+
+
+type Glob a
+    = Glob String (List String -> a)
+
+
+type GlobMatcher
+    = Literal String
+    | Star
+
+
+init : constructor -> Glob constructor
+init constructor =
+    Glob "" (\captures -> constructor)
+
+
+run : List String -> Glob a -> { match : a, pattern : String }
+run captures (Glob pattern applyCapture) =
+    { match = applyCapture captures
+    , pattern = pattern
+    }
+
+
+toPattern : Glob a -> String
+toPattern (Glob pattern applyCapture) =
+    pattern
+
+
+keep : GlobMatcher -> Glob (String -> value) -> Glob value
+keep matcher (Glob pattern applyCapture) =
+    Glob (pattern ++ matcherToPattern matcher)
+        (case matcher of
+            Literal literalString ->
+                continueNonCapturing literalString applyCapture
+
+            Star ->
+                popCapture applyCapture
+        )
+
+
+matcherToPattern : GlobMatcher -> String
+matcherToPattern matcher =
+    case matcher of
+        Literal literalString ->
+            literalString
+
+        Star ->
+            "*"
+
+
+continueNonCapturing : String -> (List String -> (String -> value)) -> (List String -> value)
+continueNonCapturing hardcodedCaptureValue applyCapture =
+    \captures ->
+        applyCapture captures hardcodedCaptureValue
+
+
+popCapture : (List String -> (String -> value)) -> (List String -> value)
+popCapture applyCapture =
+    \captures ->
+        case captures of
+            first :: rest ->
+                applyCapture rest first
+
+            [] ->
+                applyCapture [] "ERROR"
+
+
+drop : GlobMatcher -> Glob a -> Glob a
+drop matcher (Glob pattern applyCapture) =
+    Glob (pattern ++ matcherToPattern matcher)
+        (\captures ->
+            case matcher of
+                Literal literalString ->
+                    applyCapture captures
+
+                Star ->
+                    applyCapture captures
+        )
+
+
+literal : String -> GlobMatcher
+literal string =
+    Literal string
+
+
+star : GlobMatcher
+star =
+    Star

tests/GlobTests.elm

@@ -0,0 +1,45 @@
+module GlobTests exposing (all)
+
+import Expect
+import Glob
+import Test exposing (describe, only, test)
+
+
+all =
+    describe "glob"
+        [ test "literal" <|
+            \() ->
+                Glob.init identity
+                    |> Glob.keep (Glob.literal "hello")
+                    |> expect
+                        { captures = []
+                        , expectedMatch = "hello"
+                        , expectedPattern = "hello"
+                        }
+        , test "capture" <|
+            \() ->
+                Glob.init identity
+                    |> Glob.keep Glob.star
+                    |> Glob.drop (Glob.literal ".txt")
+                    |> expect
+                        { captures = [ "my-file" ]
+                        , expectedMatch = "my-file"
+                        , expectedPattern = "*.txt"
+                        }
+        ]
+
+
+expect :
+    { captures : List String
+    , expectedMatch : match
+    , expectedPattern : String
+    }
+    -> Glob.Glob match
+    -> Expect.Expectation
+expect { captures, expectedMatch, expectedPattern } glob =
+    glob
+        |> Glob.run captures
+        |> Expect.equal
+            { pattern = expectedPattern
+            , match = expectedMatch
+            }