XScript Manual · Chapter 34
JSON Object — JSON document handling
The script keyword JSON provides JSON utilities. A single process can hold multiple JSON documents identified by name, and any document can be read/written via path notation (/root/items/0/name).
| Concept | Meaning |
|---|---|
jsonName | Document identifier you choose ("recipe", "mes_response", …) |
path | Location inside the document — /key/key2/0/name (key for objects, index for arrays) |
| Result / error | Every call sets an internal flag — GetResult / GetErrorMessage |
Basic flow
// 1) Create an empty document
JSON.CreateJson("recipe");
// 2) Write values (intermediate paths are auto-created)
JSON.SetValue("recipe", "/title", "AlignRecipe");
JSON.SetValue("recipe", "/version", 2);
JSON.SetValue("recipe", "/exposure_ms", 18.5);
JSON.SetValue("recipe", "/use_filter", true);
// 3) Serialize
string text = JSON.ToJsonString("recipe");
Log(text);
// {"title":"AlignRecipe","version":2,"exposure_ms":18.5,"use_filter":true}
// 4) Save to disk
JSON.SaveJsonFile("recipe", "D:/Recipes/align.json");
// 5) Drop when done
JSON.RemoveJson("recipe");Document lifecycle
// Load into memory
JSON.LoadJsonFile("mes", "D:/Mes/inbound.json");
JSON.LoadJson ("inline", "{\"a\":1,\"b\":[2,3]}");
// Existence / clear / drop
if( JSON.Contains("mes") ) JSON.ClearJsonData("mes");
JSON.RemoveJson("mes");
JSON.RemoveAll(); // drop every registered documentWriting — SetValue (4 overloads)
JSON.SetValue("doc", "/name", "Alice"); // string
JSON.SetValue("doc", "/age", 30); // int
JSON.SetValue("doc", "/weight", 62.4); // double
JSON.SetValue("doc", "/active", true); // bool
JSON.SetNullValue("doc", "/parent_id"); // explicit nullMissing paths are auto-created — no need to call AddObject first. To write into an array index, the array itself must already exist.
Reading — GetXxxValue
string n = JSON.GetStringValue("doc", "/name"); // "Alice"
int a = JSON.GetIntValue ("doc", "/age"); // 30
double w = JSON.GetDoubleValue("doc", "/weight", -1.0); // -1.0 if missing
bool v = JSON.GetBoolValue ("doc", "/active", false); // default fallbackThe 3rd argument (default value) — returned when the key is missing or has a wrong type.
Trailing subtree
// Get all child keys/values from a node as one string
string sub = JSON.GetJsonStringByPath("doc", "/items/0");Adding objects / arrays
// Add object node
JSON.AddObject("doc", "/", "items"); // /items as empty object
JSON.AddObject("doc", "/items", "first"); // /items/first as empty object
// Add array node
JSON.AddArray ("doc", "/", "tags"); // /tags as empty array
// Push into array (one object / one array)
JSON.AddObjectToArray("doc", "/items", 1); // push 1 empty object
JSON.AddArrayToArray ("doc", "/tags", 1); // push 1 empty array
// Direct SetValue on an index also works
JSON.SetValue("doc", "/tags/0", "auto");
JSON.SetValue("doc", "/tags/1", "vision");Array maintenance
int n = JSON.GetItemCount("doc", "/tags"); // count
JSON.RemoveFromArray("doc", "/tags", 0); // delete index 0
JSON.MoveArrayItem ("doc", "/tags", 1, true); // move index 1 up (swap with 0)
JSON.MoveArrayItem ("doc", "/tags", 0, false); // move index 0 down
JSON.ClearArray ("doc", "/tags"); // clear allResult / error handling
Every call updates an internal result flag.
JSON.SetValue("doc", "/x/y/z", 1);
if( JSON.GetResult("doc") == false )
{
LogError($"JSON SetValue failed : {JSON.GetErrorMessage("doc")}");
JSON.ResetResult("doc");
}Pattern — verify after a series of calls:
JSON.ResetResult("doc");
JSON.SetValue("doc", "/a", 1);
JSON.SetValue("doc", "/b/c", 2);
JSON.SetValue("doc", "/b/arr/0", "x");
if( JSON.GetResult("doc") == false )
{
ShowMessage(EB_Ok, JSON.GetErrorMessage("doc"));
return false;
}Serialization / pretty-print
string compact = JSON.ToJsonString("doc"); // single line
string pretty = JSON.FormatJson(compact); // indentedFormatJson only transforms an input string — it doesn't touch any registered document.
Common patterns
Save / load recipe
FUNCTION SaveRecipe(string filePath)
{
JSON.CreateJson("rec");
JSON.SetValue("rec", "/exposure_ms", Data::Exposure);
JSON.SetValue("rec", "/light_pct", Data::Light);
JSON.AddArray("rec", "/", "trims");
for(i, 0, 9)
{
JSON.AddObjectToArray("rec", "/trims", 1);
JSON.SetValue("rec", $"/trims/{i}/x", Data::TrimX[i]);
JSON.SetValue("rec", $"/trims/{i}/y", Data::TrimY[i]);
}
JSON.SaveJsonFile("rec", filePath);
JSON.RemoveJson("rec");
}
FUNCTION LoadRecipe(string filePath)
{
if( JSON.LoadJsonFile("rec", filePath) == false )
{
ShowMessage(EB_Ok, $"Load failed : {JSON.GetErrorMessage("rec")}");
return false;
}
Data::Exposure = JSON.GetDoubleValue("rec", "/exposure_ms", 0);
Data::Light = JSON.GetIntValue ("rec", "/light_pct", 0);
int n = JSON.GetItemCount("rec", "/trims");
for(i, 0, n - 1)
{
Data::TrimX[i] = JSON.GetDoubleValue("rec", $"/trims/{i}/x", 0);
Data::TrimY[i] = JSON.GetDoubleValue("rec", $"/trims/{i}/y", 0);
}
JSON.RemoveJson("rec");
return true;
}Parse MES response
JSON.LoadJson("resp", responseString);
if( JSON.GetBoolValue("resp", "/ok", false) == false )
{
ShowError(EB_Reset, 1, JSON.GetStringValue("resp", "/message"));
return false;
}
int lotSeq = JSON.GetIntValue("resp", "/data/lot_seq", 0);Quick reference
| Group | Functions |
|---|---|
| Lifecycle | CreateJson · LoadJson · LoadJsonFile · SaveJsonFile · RemoveJson · RemoveAll · ClearJsonData · Contains |
| Result | GetResult · GetErrorMessage · ResetResult |
| Write | SetValue (string/int/double/bool) · SetNullValue |
| Read | GetStringValue · GetIntValue · GetDoubleValue · GetBoolValue · GetJsonStringByPath |
| Tree | AddObject · AddArray |
| Array ops | AddObjectToArray · AddArrayToArray · RemoveFromArray · ClearArray · GetItemCount · MoveArrayItem |
| Serialize | ToJsonString · FormatJson |