Introduce Address type

ethers.nimble

@@ -5,6 +5,8 @@ license = "MIT"
 
 requires "chronos >= 3.0.0 & < 4.0.0"
 requires "contractabi >= 0.4.0 & < 0.5.0"
+requires "questionable >= 0.10.2 & < 0.11.0"
+requires "stew"
 
 task test, "Run the test suite":
   exec "nimble install -d -y"

ethers/address.nim

@@ -0,0 +1,23 @@
+import pkg/stew/byteutils
+import pkg/questionable
+
+type
+  Address* = distinct array[20, byte]
+
+func init*(_: type Address, bytes: array[20, byte]): Address =
+  Address(bytes)
+
+func init*(_: type Address, hex: string): ?Address =
+  try:
+    let bytes = array[20, byte].fromHex(hex)
+    some Address.init(bytes)
+  except ValueError:
+    none Address
+
+func toArray(address: Address): array[20, byte] =
+  array[20, byte](address)
+
+func `$`*(address: Address): string =
+  "0x" & toHex(address.toArray)
+
+func `==`*(a, b: Address): bool {.borrow.}

testmodule/test.nim

@@ -1 +1,4 @@
+import ./testAddress
+import ./testJsonRpcProvider
+
 {.warning[UnusedImport]:off.}

testmodule/testAddress.nim

@@ -0,0 +1,25 @@
+import std/unittest
+import pkg/ethers/address
+import pkg/questionable
+
+suite "Address":
+
+  let address = Address.init [
+    0x1'u8, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa,
+    0x1   , 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa
+  ]
+
+  test "can be converted to string":
+    check $address == "0x0102030405060708090a0102030405060708090a"
+
+  test "can be parsed from string":
+    check:
+      Address.init("0x0102030405060708090a0102030405060708090a") == some address
+
+  test "parsing fails when string does not contain proper hex":
+    check:
+      Address.init("0xfoo2030405060708090a0102030405060708090a") == none Address
+
+  test "parsing fails when string does not contain 20 bytes":
+    check:
+      Address.init("0x0102030405060708090a010203040506070809") == none Address