address #7430: to

lib/pure/conv.nim

@@ -0,0 +1,28 @@
+#
+#
+#            Nim's Runtime Library
+#        (c) Copyright 2018 Nim contributors
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+##[
+Universal conversion template.
+Usage:
+.. code-block:: nim
+      import conv
+      echo "yes".to(bool)
+      echo "0034".to(int)
+
+Design:
+each specialized `to` overload should belong in its respective module, eg:
+`parseJson` in `lib/pure/json.nim`
+to avoid making this module pull in all dependencies
+]##
+
+import strutils
+
+template to*(source: string; dest: typedesc[bool]): untyped = parseBool(source)
+template to*(source: string; dest: typedesc[int]): untyped = parseInt(source)
+template to*(source: string; dest: typedesc[float]): untyped = parseFloat(source)

lib/pure/json.nim

@@ -1339,6 +1339,8 @@ else:
   proc parseJson*(buffer: string): JsonNode =
     return parseNativeJson(buffer).convertObject()
 
+template to*(source: string; dest: typedesc[JsonNode]): untyped = parseJson(source)
+
 # -- Json deserialiser macro. --
 
 proc createJsonIndexer(jsonNode: NimNode,

tests/stdlib/tconv.nim

@@ -0,0 +1,6 @@
+import conv
+
+doAssert "true".to(bool) == true
+doAssert "yes".to(bool) == true
+doAssert "0034".to(int) == 34
+doAssert "1.5".to(float) == 1.5

tests/stdlib/tjsonmacro.nim

@@ -142,6 +142,19 @@ when isMainModule:
     except:
       doAssert false
 
+  # Test parseJson vs to
+  block:
+    let str = """
+      {
+        "person": {
+          "name": "Nimmer",
+          "age": 21
+        },
+        "list": [1, 2, 3, 4]
+      }
+    """
+    doAssert str.parseJson == str.to(JsonNode)
+
   # Test the example in json module.
   block:
     let jsonNode = parseJson("""