Add SimpleLERP node

Implement a linear-interpolation math node that maps an input value
from an input range [in_min, in_max] onto an output range
[out_min, out_max].

- node.py: SimpleLERP class (classic INPUT_TYPES/RETURN_TYPES pattern),
  float inputs for value and both ranges, plus a clamp toggle. Guards
  against a zero-width input range and supports inverted ranges.
- __init__.py: export NODE_CLASS_MAPPINGS / NODE_DISPLAY_NAME_MAPPINGS
  for ComfyUI discovery.
- README.md: usage, formula, and inputs/outputs tables.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -1,2 +1,36 @@
 # comfyui-lerp-node
 A simple math node that performs linear interpolation between a base range and a mapped range.
+
+## SimpleLERP
+
+Maps an input `value` from an input range `[in_min, in_max]` onto an output range
+`[out_min, out_max]`:
+
+```
+t      = (value - in_min) / (in_max - in_min)
+output = out_min + t * (out_max - out_min)
+```
+
+Found in the node browser under the **math** category as **Simple LERP**.
+
+### Inputs
+
+| Name      | Type    | Default | Description                                                        |
+|-----------|---------|---------|--------------------------------------------------------------------|
+| `value`   | FLOAT   | 0.0     | The value to map.                                                  |
+| `in_min`  | FLOAT   | 0.0     | Lower bound of the input range.                                    |
+| `in_max`  | FLOAT   | 1.0     | Upper bound of the input range.                                    |
+| `out_min` | FLOAT   | 0.0     | Lower bound of the output range.                                   |
+| `out_max` | FLOAT   | 1.0     | Upper bound of the output range.                                   |
+| `clamp`   | BOOLEAN | False   | If true, hold the result within the output range instead of extrapolating. |
+
+### Output
+
+| Name    | Type  | Description                |
+|---------|-------|----------------------------|
+| `value` | FLOAT | The interpolated result.   |
+
+Notes:
+- With `clamp` off, inputs outside `[in_min, in_max]` extrapolate beyond the output range.
+- Inverted ranges (e.g. `out_min > out_max`) are supported.
+- If `in_min == in_max`, the result is `out_min` (no division by zero).

__init__.py

@@ -0,0 +1,3 @@
+from .node import NODE_CLASS_MAPPINGS, NODE_DISPLAY_NAME_MAPPINGS
+
+__all__ = ["NODE_CLASS_MAPPINGS", "NODE_DISPLAY_NAME_MAPPINGS"]

node.py

@@ -0,0 +1,40 @@
+class SimpleLERP:
+    """Linear interpolation: map a value from an input range to an output range."""
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        flt = {"default": 0.0, "min": -1e9, "max": 1e9, "step": 0.01}
+        return {
+            "required": {
+                "value": ("FLOAT", flt),
+                "in_min": ("FLOAT", {**flt, "default": 0.0}),
+                "in_max": ("FLOAT", {**flt, "default": 1.0}),
+                "out_min": ("FLOAT", {**flt, "default": 0.0}),
+                "out_max": ("FLOAT", {**flt, "default": 1.0}),
+                "clamp": ("BOOLEAN", {"default": False}),
+            }
+        }
+
+    RETURN_TYPES = ("FLOAT",)
+    RETURN_NAMES = ("value",)
+    FUNCTION = "lerp"
+    CATEGORY = "math"
+
+    def lerp(self, value, in_min, in_max, out_min, out_max, clamp):
+        in_span = in_max - in_min
+        if in_span == 0:
+            # Degenerate input range: nothing to interpolate across.
+            result = out_min
+        else:
+            t = (value - in_min) / in_span
+            result = out_min + t * (out_max - out_min)
+
+        if clamp:
+            lo, hi = min(out_min, out_max), max(out_min, out_max)
+            result = max(lo, min(hi, result))
+
+        return (result,)
+
+
+NODE_CLASS_MAPPINGS = {"SimpleLERP": SimpleLERP}
+NODE_DISPLAY_NAME_MAPPINGS = {"SimpleLERP": "Simple LERP"}