feat(table): ✨ first implementation of pointer system in zencode

More testing is needed before merging

src/lua/zencode_table.lua

@@ -267,3 +267,39 @@ When("create the copy of last element in ''", function(obj_name)
     end
     new_codec('copy_of_last_element', n_codec)
 end)
+
+When("set pointer to ''", function(obj_name)
+    local obj, obj_codec = have(obj_name)
+    empty "pointer"
+    zencode_assert(obj_codec.zentype ~= "e", "Cannot set pointer to an element")
+    ACK.pointer = obj
+    new_codec("pointer", nil, obj_name)
+end)
+
+When("enter '' with pointer", function(key_name)
+         local key_o, key_codec = mayhave(key_name)
+         local p, p_codec = have("pointer")
+         local key_s
+         if key_o then
+             key_s = get_encoding_function(key_codec.encoding)(key_o)
+         else
+             key_s = key_name
+         end
+         if p_codec.zentype == "a" then
+             key_s = tonumber(key_s)
+             zencode_assert(key_s, "Pointer is an array but key is not a position number: "..key_name)
+         end
+         zencode_assert(p[key_s], "Cannot find "..key_s.." in pointer")
+         zencode_assert(luatype(p[key_s]) == "table",
+                        "Cannot enter a "..luatype(p[key_s])..", is not a table")
+         -- do not point to elements
+         zencode_assert(not p_codec.schema, "Cannot set pointer to an element")
+         ACK.pointer = p[key_s]
+         local n_codec = {encoding = p_codec.encoding}
+         if p_codec.schema then
+             n_codec.schema = p_codec.schema
+             n_codec.zentype = "e"
+         end
+         CODEC.pointer = nil
+         new_codec("pointer", n_codec)
+end)

test/zencode/table.bats

@@ -0,0 +1,68 @@
+load ../bats_setup
+load ../bats_zencode
+SUBDOC=table
+
+
+@test "move with pointer" {
+cat <<EOF | save_asset pointer.data
+{ 
+  "dataFromEndpoint": {
+    "cod": "200",
+    "count": 1,
+    "list": [
+      {
+        "clouds": {
+          "all": 20
+        },
+        "coord": {
+          "lat": 43.7667,
+          "lon": 11.25
+        },
+        "dt": 1624277371,
+        "id": 3176959,
+        "main": {
+          "feels_like": 305.32,
+          "humidity": 48,
+          "pressure": 1010,
+          "temp": 304.11,
+          "temp_max": 304.82,
+          "temp_min": 303.15
+        },
+        "name": "Florence",
+        "sys": {
+          "country": "IT"
+        },
+        "weather": [
+          {
+            "description": "few clouds",
+            "icon": "02d",
+            "id": 801,
+            "main": "Clouds"
+          }
+        ],
+        "wind": {
+          "deg": 0,
+          "speed": 2.06
+        }      }
+    ],
+    "message": "accurate"
+  },
+  "key_inside_list": "main"
+}
+EOF
+cat <<EOF | zexe pointer.zen pointer.data
+Given I have a 'string dictionary' named 'dataFromEndpoint'
+and I have a 'string' named 'key_inside_list'
+
+When I set pointer to 'dataFromEndpoint'
+and I enter 'list' with pointer
+and I enter '1' with pointer
+and I enter 'key_inside_list' with pointer
+and I move 'key_inside_list' in 'pointer'
+
+Then print 'pointer'
+and print 'dataFromEndpoint'
+EOF
+    save_output 'pointer.out'
+    assert_output '{"dataFromEndpoint":{"cod":"200","count":1,"list":[{"clouds":{"all":20},"coord":{"lat":43.7667,"lon":11.25},"dt":1.624277e+09,"id":3176959.0,"main":{"feels_like":305.32,"humidity":48,"key_inside_list":"main","pressure":1010,"temp":304.11,"temp_max":304.82,"temp_min":303.15},"name":"Florence","sys":{"country":"IT"},"weather":[{"description":"few clouds","icon":"02d","id":801,"main":"Clouds"}],"wind":{"deg":0,"speed":2.06}}],"message":"accurate"},"pointer":{"feels_like":305.32,"humidity":48,"key_inside_list":"main","pressure":1010,"temp":304.11,"temp_max":304.82,"temp_min":303.15}}'
+}