fix: skip unimplemented dtypes in from-scalar example

[Planeshifter]

Description

This pull request:

• Adds a guard in @stdlib/ndarray/from-scalar example to skip float16 and complex32 dtypes, whose buffer constructors in @stdlib/ndarray/base/buffer-ctors are placeholder notImplemented functions that throw Error: not implemented when invoked as constructors.

The example iterates over all dtypes returned by dtypes() (which includes every registered dtype in dtypes.json). For float16 and complex32, the internal call chain is:

scalar2ndarray(i, { dtype: 'float16' })
  → buffer('float16', 1)
    → bufferCtors('float16')   // returns notImplemented (truthy)
      → new notImplemented(1)  // throws Error: not implemented

The if (buf === null) guard in from-scalar/lib/main.js never fires because the throw happens before buffer() can return. The fix skips these two dtypes in the example until their constructors are implemented (tracked by the FIXME comments in buffer-ctors/lib/ctors.js).

This resolves the random_examples CI job failure seen in workflow run 27923327635.

Related Issues

• No dedicated issue; failure surfaced via CI job random_examples on develop.

Questions

No.

Other

No.

Checklist

• Read, understood, and followed the contributing guidelines.

AI Assistance

• Yes

• Code generation (e.g., when writing an implementation or fixing a bug)

• Research and understanding

Disclosure

This PR was written primarily by Claude Code as part of an automated CI failure investigation routine. The root cause was identified by tracing the call chain from the failing example through @stdlib/ndarray/base/buffer and @stdlib/ndarray/base/buffer-ctors. The fix was validated by running the example locally and by three independent automated reviewers (correctness, regression, and style checks).

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@stdlib-js/reviewers

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
ndarray/from-scalar	$\\color{red}230/232$ $\\color{green}+99.14\\%$	$\\color{red}30/31$ $\\color{green}+96.77\\%$	$\\color{green}1/1$ $\\color{green}+100.00\\%$	$\\color{red}230/232$ $\\color{green}+99.14\\%$

The above coverage report was generated for the changes in this PR.