Scripting: named signal vars, shared vars dict, control scripts, code templates

- Named variables in expressions: source channel IDs injected as Python
  identifiers alongside x[] (e.g. write `A0 * 2` instead of `x[0] * 2`)
- Shared `vars` dict on SignalProcessor accessible from all expressions,
  functions, and control scripts; persisted in .labdaq profiles
- Per-derived-channel `state` dict for persistent computation state in
  custom scripts
- Control widgets gain optional on_action_script (Python snippet with
  value, vars, channels, math in scope); syntax-checked in editor dialog
- Built-in derived kinds (derivative, rms, power, etc.) now show their
  Python implementation as read-only code previews; "Edit as Custom Script"
  converts to custom_script kind with template pre-filled

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 56 insertions, 2 deletions

diff --git a/ui/control_editor.py b/ui/control_editor.py
index c582e6b..48de21d 100644
--- a/ui/control_editor.py
+++ b/ui/control_editor.py
@@ -18,8 +18,10 @@ from PyQt6.QtWidgets import (
     QLabel, QLineEdit, QComboBox, QDoubleSpinBox,
     QSpinBox, QPushButton, QGroupBox, QWidget,
     QStackedWidget, QFrame, QCheckBox, QSizePolicy,
+    QTextEdit, QScrollArea,
 )
 from PyQt6.QtCore import Qt
+from PyQt6.QtGui import QFont, QFontMetrics
 
 
 class _DynStack(QStackedWidget):
@@ -68,6 +70,8 @@ class ControlSpec:
     max_val:      float = 100.0
     step:         float = 1.0
     max_rpm:      int   = 3000
+    # Optional Python snippet executed on every value change
+    on_action_script: str = ""
 
     def to_dict(self) -> dict:
         return asdict(self)
@@ -177,8 +181,8 @@ class ControlEditorDialog(QDialog):
         self.result_spec: Optional[ControlSpec] = None
 
         self.setWindowTitle("Edit Control" if spec else "Add Control")
-        self.setMinimumSize(440, 460)
-        self.resize(460, 500)
+        self.setMinimumSize(440, 520)
+        self.resize(460, 580)
         self._build()
         self._load_spec()
 
@@ -244,6 +248,40 @@ class ControlEditorDialog(QDialog):
             self._stack.addWidget(panel)
         params_lay.addWidget(self._stack)
         root.addWidget(self._params_grp)
+
+        # ── On-action script ───────────────────────────────────────────
+        script_grp = QGroupBox("On Action Script  (optional)")
+        script_lay = QVBoxLayout(script_grp); script_lay.setContentsMargins(10, 12, 10, 10)
+
+        _help = QLabel(
+            "Runs every time this control changes value.\n"
+            "Available: value, channel_id, device_id, vars (shared dict), "
+            "channels (latest values by channel_id), math"
+        )
+        _help.setObjectName("traceSource"); _help.setWordWrap(True)
+        script_lay.addWidget(_help)
+
+        _mono = QFont("IBM Plex Mono, Consolas, Monospace")
+        _mono.setStyleHint(QFont.StyleHint.Monospace)
+        self._script_edit = QTextEdit()
+        self._script_edit.setFont(_mono)
+        self._script_edit.setTabStopDistance(QFontMetrics(_mono).horizontalAdvance(" ") * 4)
+        self._script_edit.setMinimumHeight(80); self._script_edit.setMaximumHeight(160)
+        self._script_edit.setPlaceholderText(
+            "# Example: zero a position offset when button is pressed\n"
+            "# vars['zero_pos'] = channels.get('encoder_0', 0)"
+        )
+        script_lay.addWidget(self._script_edit)
+
+        self._script_status = QLabel("")
+        self._script_status.setObjectName("traceSource")
+        check_btn = QPushButton("Check Syntax")
+        check_btn.clicked.connect(self._check_script)
+        btn_row = QHBoxLayout()
+        btn_row.addWidget(self._script_status, 1)
+        btn_row.addWidget(check_btn)
+        script_lay.addLayout(btn_row)
+        root.addWidget(script_grp)
         root.addStretch()
 
         # ── Buttons ────────────────────────────────────────────────────
@@ -258,6 +296,18 @@ class ControlEditorDialog(QDialog):
         btn_row.addWidget(cancel); btn_row.addWidget(ok)
         root.addLayout(btn_row)
 
+    def _check_script(self):
+        src = self._script_edit.toPlainText().strip()
+        if not src:
+            self._script_status.setText(""); return
+        try:
+            compile(src, "<script>", "exec")
+            self._script_status.setText("✓ OK")
+            self._script_status.setStyleSheet("color:#22c55e;")
+        except SyntaxError as e:
+            self._script_status.setText(f"⚠ {e}")
+            self._script_status.setStyleSheet("color:#ef4444;")
+
     def _load_spec(self):
         """Populate fields from self.spec."""
         # Type
@@ -287,6 +337,9 @@ class ControlEditorDialog(QDialog):
         for name, panel in self._param_panels.items():
             panel.load(self.spec)
 
+        # Script
+        self._script_edit.setPlainText(self.spec.on_action_script)
+
     def _on_type_changed(self, type_name: str):
         idx = list(_PARAM_PANELS.keys()).index(type_name)
         self._stack.setCurrentIndex(idx)
@@ -340,6 +393,7 @@ class ControlEditorDialog(QDialog):
             device_id=self._dev_cb.currentData() or "",
             channel_id=channel_id,
             active_low=self._active_low_chk.isChecked(),
+            on_action_script=self._script_edit.toPlainText().strip(),
         )
         # Save type-specific params
         panel = self._param_panels.get(ctype)