Update data mapping ergonomics

[ericpan64]

Closes N/A

Background

• Makes the README more clear (removes unused components)
• Simplifies DSL

Design (high-level)

• Use function chaining instead of | syntax
• Add concrete example

Other notes

---

Summary by cubic

Streamlines the data mapping API by removing DataMapping, consolidating functionality into Mapper, and adding ergonomic method chaining and multi-path extraction in partials. This reduces boilerplate and makes transformations easier to read.

• New Features

  • Method chaining in partials: p.get("a.b").join(" ").upper() (pipe syntax still supported).
  • Multi-path extraction: p.get(["name.first", "name.given[*]", "name.suffix"]) with join(flatten=True).
  • Mapper now takes transformations and optional output_schema; accepts Mapping types.
  • Input schemas are metadata only via min_input_schemas/other_input_schemas; auto mode strictness now depends only on output_schema.
  • README rewritten with clearer examples; version bumped to 0.1.5.

• Migration

  • Replace DataMapping + Mapper with a single Mapper(transformations, output_schema=...).
  • Remove input_schema usage; use min_input_schemas/other_input_schemas for documentation only. No input validation is performed.
  • Update partials where desired to method chaining; p.get can take lists; join supports flatten=True.
  • Remove any imports/references to DataMapping (no longer exported).

[cubic-dev-ai]

2 issues found across 13 files

Prompt for AI agents (all 2 issues)

Understand the root cause of the following 2 issues and fix them.


<file name="chidian/mapper.py">

<violation number="1" location="chidian/mapper.py:152">
Short-circuiting flexible mode without an output schema bypasses _execute_flexible, so transform exceptions now raise instead of being captured as ValidationIssues. Please route this case through _execute_flexible to preserve flexible-mode error handling.</violation>
</file>

<file name="chidian/partials.py">

<violation number="1" location="chidian/partials.py:68">
Passing arguments to chainable methods like `strip(&#39; ,&#39;)` throws a TypeError because `attr(*args, **kwargs)` calls descriptors without the value. Wrap the call so the value becomes the first argument.</violation>
</file>

_{React with 👍 or 👎 to teach cubic. Mention @cubic-dev-ai to give feedback, ask questions, or re-run the review.}

[cubic-dev-ai]

Short-circuiting flexible mode without an output schema bypasses _execute_flexible, so transform exceptions now raise instead of being captured as ValidationIssues. Please route this case through _execute_flexible to preserve flexible-mode error handling.

Prompt for AI agents

Address the following comment on chidian/mapper.py at line 152:

<comment>Short-circuiting flexible mode without an output schema bypasses _execute_flexible, so transform exceptions now raise instead of being captured as ValidationIssues. Please route this case through _execute_flexible to preserve flexible-mode error handling.</comment>

<file context>
@@ -107,9 +148,9 @@ def __call__(self, data: Any) -&gt; Any | MapperResult:
-        if self._backward_compat and not self.data_mapping.has_schemas:
-            return self.data_mapping.transform(data)
+        # For non-schema mode, just return dict
+        if not self.has_schemas and self.mode == ValidationMode.FLEXIBLE:
+            return self.transform(data)
 
</file context>

[cubic-dev-ai]

Passing arguments to chainable methods like strip(' ,') throws a TypeError because attr(*args, **kwargs) calls descriptors without the value. Wrap the call so the value becomes the first argument.

Prompt for AI agents

Address the following comment on chidian/partials.py at line 68:

<comment>Passing arguments to chainable methods like `strip(&#39; ,&#39;)` throws a TypeError because `attr(*args, **kwargs)` calls descriptors without the value. Wrap the call so the value becomes the first argument.</comment>

<file context>
@@ -44,9 +44,52 @@ def __len__(self) -&gt; int:
+                    new_op = (
+                        attr
+                        if not args and not kwargs
+                        else (lambda v: attr(*args, **kwargs)(v))
+                    )
+                    return FunctionChain(*self.operations, new_op)
</file context>

Suggested change

	else (lambda v: attr(*args, **kwargs)(v))
	else (lambda v: attr.func(v, *args, **kwargs))