Fix library configuration with new submodules.

cliutils/config.nim

@@ -0,0 +1,64 @@
+import docopt, json, nre, os, strtabs, strutils
+
+type
+  CombinedConfig* = object
+    docopt*: Table[string, Value]
+    json*: JsonNode
+
+template walkFieldDefs*(t: NimNode, body: untyped) =
+  let tTypeImpl = t.getTypeImpl
+
+  var nodeToItr: NimNode
+  if tTypeImpl.typeKind == ntyObject: nodeToItr = tTypeImpl[2]
+  elif tTypeImpl.typeKind == ntyTypeDesc: nodeToItr = tTypeImpl.getType[1].getType[2]
+  else: error $t & " is not an object or type desc (it's a " & $tTypeImpl.typeKind & ")."
+
+  for fieldDef {.inject.} in nodeToItr.children:
+    # ignore AST nodes that are not field definitions
+    if fieldDef.kind == nnkIdentDefs:
+      let fieldIdent {.inject.} = fieldDef[0]
+      let fieldType {.inject.} = fieldDef[1]
+      body
+
+    elif fieldDef.kind == nnkSym:
+      let fieldIdent {.inject.} = fieldDef
+      let fieldType {.inject.} = fieldDef.getType
+      body
+
+
+# TODO: Generic config loader
+# macro loadConfig*(filePath: string, cfgType: typed, args: Table[string, docopt.Value): untyped =
+#   result = newNimNode(nnkObjConstr).(cfgType)
+#
+#   var idx = 0
+#   cfgType.walkFieldDefs:
+#     let valLookup = quote do: `getVal`(
+
+proc getVal*(cfg: CombinedConfig, key: string): string =
+  let argKey = "--" & key
+  let envKey = key.replace('-', '_').toUpper
+  let jsonKey = key.replace(re"(-\w)", proc (m: RegexMatch): string = ($m)[1..1].toUpper)
+
+  if cfg.docopt.contains(argKey) and cfg.docopt[argKey]: return $cfg.docopt[argKey]
+  elif existsEnv(envKey): return getEnv(envKey)
+  elif cfg.json.hasKey(jsonKey):
+    let node = cfg.json[jsonKey]
+    case node.kind
+    of JString: return node.getStr
+    of JInt: return $node.getInt
+    of JFloat: return $node.getFloat
+    of JBool: return $node.getBool
+    of JNull: return ""
+    of JObject: return $node
+    of JArray: return $node
+  else: raise newException(ValueError, "cannot find a configuration value for \"" & key & "\"")
+
+proc getVal*(cfg: CombinedConfig, key, default: string): string =
+  try: return getVal(cfg, key)
+  except: return default
+
+proc loadEnv*(): StringTableRef =
+  result = newStringTable()
+
+  for k, v in envPairs():
+    result[k] = v