add match!

src/wf_artifacts/drafts/__init__.py

@@ -11,6 +11,8 @@ from .models import (
     DraftForeachStep,
     DraftInterruptStep,
     DraftJoinStep,
+    DraftMatchCase,
+    DraftMatchStep,
     DraftWhenStep,
     DraftUseStep,
     WorkflowDraft,
@@ -23,6 +25,8 @@ __all__ = [
     "DraftForeachStep",
     "DraftInterruptStep",
     "DraftJoinStep",
+    "DraftMatchCase",
+    "DraftMatchStep",
     "DraftWhenStep",
     "DraftUseStep",
     "WorkflowDraft",

src/wf_artifacts/drafts/adapter.py

@@ -1,16 +1,18 @@
 from __future__ import annotations
 
 from wf_authoring import WorkflowBuilder
+from wf_authoring.dsl import PathExpr
 from wf_core import JoinNode, Workflow
 
 from .models import (
+    DraftChooseStep,
     DraftForeachStep,
     DraftInterruptStep,
     DraftJoinStep,
+    DraftMatchStep,
     DraftStep,
     DraftUseStep,
     DraftWhenStep,
-    DraftChooseStep,
     WorkflowDraft,
 )
 
@@ -79,4 +81,11 @@ def _add_step(builder: WorkflowBuilder, step_id: str, step: DraftStep):
             id=step_id,
             default=step.choose.default,
         ).entry
+    if isinstance(step, DraftMatchStep):
+        return builder.match(
+            PathExpr(step.match.value),
+            {case.equals: case.then for case in step.match.cases},
+            id=step_id,
+            default=step.match.default,
+        ).entry
     raise TypeError(f"unsupported draft step {type(step)!r}")

src/wf_artifacts/drafts/models.py

@@ -7,7 +7,9 @@ from pydantic import BaseModel, Field, model_validator
 from wf_core.models.conditions import Condition
 
 JsonObject = dict[str, Any]
-STEP_KIND_KEYS = frozenset({"use", "foreach", "interrupt", "join", "when", "choose"})
+STEP_KIND_KEYS = frozenset(
+    {"use", "foreach", "interrupt", "join", "when", "choose", "match"}
+)
 
 
 class DraftUseStep(BaseModel):
@@ -91,6 +93,27 @@ class DraftChooseStep(BaseModel):
     choose: DraftChoosePayload
 
 
+class DraftMatchCase(BaseModel):
+    """One ordered equality case in a draft match decision."""
+
+    equals: Any
+    then: str
+
+
+class DraftMatchPayload(BaseModel):
+    """Payload for matching one graph value against ordered equality cases."""
+
+    value: str
+    cases: list[DraftMatchCase] = Field(min_length=1)
+    default: str = "__end__"
+
+
+class DraftMatchStep(BaseModel):
+    """Draft step that delegates equality decisions to `WorkflowBuilder.match`."""
+
+    match: DraftMatchPayload
+
+
 DraftStep = (
     DraftUseStep
     | DraftForeachStep
@@ -98,6 +121,7 @@ DraftStep = (
     | DraftJoinStep
     | DraftWhenStep
     | DraftChooseStep
+    | DraftMatchStep
 )