Move parser into packages/parser

packages/parser/src/Bytes.Parser.roc

@@ -0,0 +1,39 @@
+##
+##
+## Parse an [IPv4](https://en.wikipedia.org/wiki/IPv4) address:
+##
+## parser : Parser Ip4
+## parser =
+##     a <- keep u8
+##     _ <- skip (usv '.')
+##     b <- keep u8
+##     _ <- skip (usv '.')
+##     c <- keep u8
+##     _ <- skip (usv '.')
+##     d <- keep u8
+##
+##     Parser.succeed (Ip4.fromOctets a b c d)
+
+
+interface Parser
+    exposes [ Parser ]
+    imports []
+
+Parser a :
+    [
+        @Parser (Bytes -> Result { answer : a, rest : Bytes } RawProblem)
+    ]
+
+RawProblem : [ ... ]
+
+keep : Parser a, (a -> Parser b) -> Parser b
+
+skip : Parser *, ({} -> Parser b) -> Parser b
+
+str : Parser Str
+
+u8 : Parser U8
+u8 = @Parser Str.parseU8 # TODO doesn't work for bytes!
+                         # TODO do we need a separate parser for Str vs Bytes because of encoding?  e.g. Parser.Bytes.utf8
+
+i8 : Parser I8

packages/parser/src/Parser.roc

@@ -0,0 +1,72 @@
+##
+##
+## Parse an [IPv4](https://en.wikipedia.org/wiki/IPv4) address:
+##
+## parser : Parser Ip4
+## parser =
+##     a <- keep u8
+##     _ <- skip (usv '.')
+##     b <- keep u8
+##     _ <- skip (usv '.')
+##     c <- keep u8
+##     _ <- skip (usv '.')
+##     d <- keep u8
+##
+##     Parser.succeed (Ip4.fromOctets a b c d)
+
+
+interface Parser
+    exposes [ Parser ]
+    imports []
+
+Parser a :
+    [
+        @Parser (Str -> Result { answer : a, rest : Str } RawProblem),
+    ]
+
+RawProblem :
+    [
+        Expected
+            [
+                NumU8,
+                NumI8,
+                NumU16,
+                NumI16,
+                NumU32,
+                NumI32,
+                NumU64,
+                NumI64,
+                NumU128,
+                NumI128,
+                NumF64,
+                NumF32,
+                End
+            ]
+    ]
+
+keep : Parser a, (a -> Parser b) -> Parser b
+
+skip : Parser *, ({} -> Parser b) -> Parser b
+
+symbol : Str -> Parser {}
+symbol = \symbol -> @Parser Str.chompStr symbol
+
+u8 : Parser U8
+u8 = @Parser Str.parseU8
+
+i8 : Parser I8
+i8 = @Parser Str.parseI8
+
+end : Parser {}
+end = @Parser \str ->
+    if Str.isEmpty str then
+        Ok {}
+    else
+        Err (Expected End)
+
+lazy : ({} -> Parser a) -> Parser a
+lazy = \thunk ->
+    @Parser \str ->
+        @Parser parse = thunk {}
+
+        parse str