← Back to home
Comparison · Analytics

constants vs vellum

A side-by-side editorial comparison of constants and vellum — release velocity, themes, recent moves, and the top alternatives to consider.

constants vs vellum: at a glance

Featureconstantsvellum
SectorAnalyticsAnalytics
Velocity score0.05.0
Sparks · 30d00
Top themesphysical-constants, codata, units, uncertainty-propagationr-graphics, rendering-engine, linting, accessibility
Last editorial update1h ago7h ago
WebsiteVisit →Visit →

What is constants?

The R package for CODATA constants rebuilt its symbol table on NIST's naming so future updates stop being hand work.

constants exposes the CODATA recommended values of the physical constants to R, as a data frame plus symbol lists that carry units, uncertainties, or both. The package reached 1.0.0 on the 2018 CODATA release and has shipped once since, purely to track a units package update. Its surface is small and its release cadence is bound to CODATA, which revises every few years.

Read the full constants trajectory →

What is vellum?

vellum's bugs are now found by using it, not testing it — the downstream grammar is doing the QA.

The rendering engine shipped nine releases in the two weeks around the end of July, six of them on a single day. Almost every entry is a correctness fix in a capability that worked when drawn and failed when measured, or worked in isolation and failed in composition. The release notes are unusually forensic: each one states the mechanism, the observable symptom, and why the fix mirrors the draw path rather than reimplementing it.

Read the full vellum trajectory →

constants vs vellum: editorial side-by-side

C
constants
ANALYTICS
0.0

The R package for CODATA constants rebuilt its symbol table on NIST's naming so future updates stop being hand work.

◆ Current state

constants exposes the CODATA recommended values of the physical constants to R, as a data frame plus symbol lists that carry units, uncertainties, or both. The package reached 1.0.0 on the 2018 CODATA release and has shipped once since, purely to track a units package update. Its surface is small and its release cadence is bound to CODATA, which revises every few years.

◆ Where it's heading

The direction set at 1.0.0 was to stop being a curated convenience wrapper and become a mechanical mirror of NIST. Hand-crafted symbol names were replaced with NIST's own ASCII symbols, categories adopted NIST's, and uncertainty switched from relative to absolute — all framed by the maintainer as necessary to make future CODATA updates routine. On top of that the package gained a correlation matrix and optional integration with the quantities package, moving it from a lookup table toward something that can propagate uncertainty.

◆ Prediction

Having rebuilt the symbol table specifically so CODATA revisions become mechanical, the next substantive release most likely tracks a new CODATA dataset rather than adding API. The experimental correlated-value support, disabled by default at 1.0.0, is the one part these entries flag as unfinished.

V
vellum
ANALYTICS
5.0

vellum's bugs are now found by using it, not testing it — the downstream grammar is doing the QA.

◆ Current state

The rendering engine shipped nine releases in the two weeks around the end of July, six of them on a single day. Almost every entry is a correctness fix in a capability that worked when drawn and failed when measured, or worked in isolation and failed in composition. The release notes are unusually forensic: each one states the mechanism, the observable symptom, and why the fix mirrors the draw path rather than reimplementing it.

◆ Where it's heading

The pivotal detail is stated outright in 0.6.3 — the first bug in the series found by using the engine from vellumplot rather than testing it in isolation. Every release since names the downstream as the source: the contrast rule's false positives, the lint rules that fired on all five sample plots, the keyed roundrect batch. A rendering engine with a real grammar built on top of it is now getting the integration coverage that unit tests structurally cannot provide, and the fixes are converging on one theme: the measurement path and the draw path must not drift.

◆ Prediction

Expect the release rate to fall as the vellumplot integration surface is exhausted, with remaining work concentrated in the lint rule set now that it is meant to gate builds rather than just inform.

Alternatives to constants and vellum

Other Analytics products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either constants or vellum.

See all constants alternatives → · See all vellum alternatives →

Recent activity from constants and vellum

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 11d agovellumLinter grows to 20 rules and stops firing on every plot
  2. 13d agovellumAnimated SVGs no longer blink once and vanish or play in reverse
  3. 14d agovellumPick table now reports device pixels instead of two coordinate systems
  4. 15d agovellumContrast rule stops flagging every plot; gridlines become PDF artifacts
  5. 15d agovellumgrobwidth and grobheight now measure wrapped text, not the unwrapped line
  6. 15d agovellumKeyed roundrect becomes a real batch after downstream integration exposes it
  7. 5y agoconstantsCompatibility fix for units 0.7-0
  8. 5y agoconstantsconstants 1.0.0
  9. 8y agoconstantsUnit handling fixes ahead of the 1.0.0 rebuild

Frequently asked questions

What is the difference between constants and vellum?

They serve adjacent needs but don't currently overlap on shipped themes. vellum is currently shipping more aggressively (velocity 5.0 vs 0.0), with 0 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.

Is constants better than vellum?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. vellum is currently shipping more aggressively (velocity 5.0 vs 0.0), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Analytics products to evaluate alongside.

What are the best alternatives to constants?

Top constants alternatives in Analytics are ranked by recent ship velocity. Browse the "constants alternatives" section above for the current picks, or visit /alternatives/constants-r for the full list with editorial commentary on each.

What are the best alternatives to vellum?

Top vellum alternatives in Analytics are ranked by recent ship velocity. Browse the "vellum alternatives" section above for the current picks, or visit /alternatives/vellum-r for the full list with editorial commentary on each.