Add descriptions.tsv to the schema

src/schema/objects/columns.yaml

@@ -110,6 +110,13 @@ derived_from:
     for example a slice of tissue (`sample-02`) derived from a block of tissue (`sample-01`).
   type: string
   pattern: ^sample-[0-9a-zA-Z]+$
+desc_id:
+  name: desc_id
+  display_name: Description Label
+  description: |
+    A `desc-<label>` entity present in the derivatives dataset.
+  type: string
+  pattern: ^desc-[0-9a-zA-Z]+$
 description:
   name: description
   display_name: Description
@@ -122,6 +129,12 @@ description__optode:
   description: |
     Free-form text description of the optode, or other information of interest.
   type: string
+description__descriptions:
+  name: description
+  display_name: Description
+  description: |
+    Free-form text description of the desc entity's label (defined in `desc_id`).
+  type: string
 dimension:
   name: dimension
   display_name: Dimension

src/schema/objects/files.yaml

@@ -126,3 +126,8 @@ stimuli:
     A directory to store any stimulus files used during an experiment.
     See the [relevant section](SPEC_ROOT/modality-specific-files/task-events.md#stimuli-directory)
     for more information.
+descriptions:
+  display_name: Descriptions Definitions
+  file_type: regular
+  description: |
+    A TSV file describing labels found for the `desc` entity in a Derivatives dataset.

src/schema/rules/files/deriv/tables.yaml

@@ -0,0 +1,7 @@
+---
+descriptions:
+  level: optional
+  stem: descriptions
+  extensions:
+    - .tsv
+    - .json

src/schema/rules/tabular_data/derivatives/common_derivatives.yaml

@@ -10,3 +10,12 @@ SegmentationLookup:
     color: optional
     mapping: optional
   index_columns: [index]
+
+Descriptions:
+  selectors:
+    - path == "descriptions.tsv"
+  columns:
+    desc_id: required
+    description__descriptions: required
+  index_columns: [desc_id]
+  additional_columns: allowed