feat(program): the windowing verdict says which way a row reads and what only data or the driver can resolve

.github/workflows/build.yml

@@ -24,7 +24,7 @@ jobs:
           fetch-depth: 0
           persist-credentials: false
       - name: Set up pixi
-        uses: prefix-dev/setup-pixi@a09b6247153796b190642a2b53fac4241043cf6f # v0.10.0
+        uses: prefix-dev/setup-pixi@f00437f565399d418b0acc85936d12c1fb668347 # v0.10.1
         with:
           locked: true
           # Off, deliberately: this job publishes the artifact a tag ships, and

.github/workflows/ci.yml

@@ -50,7 +50,7 @@ jobs:
           persist-credentials: false
 
       - name: Set up pixi
-        uses: prefix-dev/setup-pixi@a09b6247153796b190642a2b53fac4241043cf6f # v0.10.0
+        uses: prefix-dev/setup-pixi@f00437f565399d418b0acc85936d12c1fb668347 # v0.10.1
         with:
           # `--locked`: pixi.lock is the environment, and a run that quietly
           # re-solved would not be testing what a contributor has.
@@ -64,7 +64,7 @@ jobs:
       # is not a conda package. Keyed on the lockfile so a tectonic upgrade
       # gets a fresh bundle rather than a stale one.
       - name: Cache the tectonic bundle
-        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         with:
           path: ~/.cache/Tectonic
           key: tectonic-${{ runner.os }}-${{ hashFiles('pixi.lock') }}

.github/workflows/pypsa-references.yml

@@ -31,7 +31,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           persist-credentials: false
-      - uses: prefix-dev/setup-pixi@a09b6247153796b190642a2b53fac4241043cf6f # v0.10.0
+      - uses: prefix-dev/setup-pixi@f00437f565399d418b0acc85936d12c1fb668347 # v0.10.1
         with:
           run-install: false
       - name: every rung solves to its record

.github/workflows/scorecard.yml

@@ -78,6 +78,6 @@ jobs:
       # Upload the results to GitHub's code scanning dashboard (optional).
       # Commenting out will disable upload of results to your repo's Code Scanning dashboard
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@5595ccaf912efad79be6eef63a5619ff05969be3 # v4.37.6
+        uses: github/codeql-action/upload-sarif@db488ddef3bf6cb639b32c2e9a7c0a7ea8271d28 # v4.37.8
         with:
           sarif_file: results.sarif

.github/workflows/update-lockfiles.yml

@@ -18,7 +18,7 @@ jobs:
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Set up pixi
-        uses: prefix-dev/setup-pixi@a09b6247153796b190642a2b53fac4241043cf6f # v0.10.0
+        uses: prefix-dev/setup-pixi@f00437f565399d418b0acc85936d12c1fb668347 # v0.10.1
         with:
           run-install: false
       - name: Update lockfiles

.release-please-manifest.json

@@ -1,3 +1,3 @@
 {
-  ".": "0.0.0-alpha.53"
+  ".": "0.0.0-alpha.67"
 }

CHANGELOG.md

@@ -17,6 +17,110 @@ contained a literal `## [X.Y.Z]` heading, release-please inserts above the first
 `##` it finds, and so the entire release landed inside the comment and rendered
 nowhere.
 
+## [0.0.0-alpha.67](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.66...v0.0.0-alpha.67) (2026-09-02)
+
+
+### Refactoring
+
+* a built-in's one positional argument is stated once, and a degree question names the tree it walks ([#364](https://github.com/energy-models/math-spec/issues/364)) ([556af30](https://github.com/energy-models/math-spec/commit/556af3053e0bb32ca8bf60e656b9455b98068981))
+* every rule two passes shared has one home, and a docstring says what a caller needs rather than why ([#363](https://github.com/energy-models/math-spec/issues/363)) ([f24ddd3](https://github.com/energy-models/math-spec/commit/f24ddd3089da12aa75715560992822a5a3ee818b))
+* **model:** each cross-declaration rule is one method, so a refusal names the rule that raised it ([#369](https://github.com/energy-models/math-spec/issues/369)) ([b25a602](https://github.com/energy-models/math-spec/commit/b25a602d21a6bb91d597f663f8bcf0b97f95aed8))
+* **piecewise:** one block expands itself, holding its names, frame and mask once ([#367](https://github.com/energy-models/math-spec/issues/367)) ([537eadf](https://github.com/energy-models/math-spec/commit/537eadf76f52615c83235e0dfbbdd2af5fa70588))
+* resolution is one method per node kind, and each operator's dim rule is one function ([#368](https://github.com/energy-models/math-spec/issues/368)) ([c7c2833](https://github.com/energy-models/math-spec/commit/c7c283347869fbd45e0ff851d0112bfcbc09f98c))
+* **typesetting:** the legend reads what the equations returned rather than state left on the walk ([#366](https://github.com/energy-models/math-spec/issues/366)) ([db96a54](https://github.com/energy-models/math-spec/commit/db96a54d55996a9e4cc89a3f837303149475211b))
+
+## [0.0.0-alpha.66](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.65...v0.0.0-alpha.66) (2026-09-01)
+
+
+### Performance
+
+* a model loads, lowers and typesets three to eight times faster ([#357](https://github.com/energy-models/math-spec/issues/357)) ([ea6fe79](https://github.com/energy-models/math-spec/commit/ea6fe798c85118750294b642463b16aa0935065f))
+
+## [0.0.0-alpha.65](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.64...v0.0.0-alpha.65) (2026-09-01)
+
+
+### Refactoring
+
+* **language:** a translation policy and a bound's side name the values they can be, rather than being a string ([#354](https://github.com/energy-models/math-spec/issues/354)) ([d212157](https://github.com/energy-models/math-spec/commit/d2121572496bf7e624cfa5e38c348cfbed4b71ad))
+* **typesetting:** a format spells the operators the language names, rather than any string a walk happens to ask for ([#352](https://github.com/energy-models/math-spec/issues/352)) ([12b4041](https://github.com/energy-models/math-spec/commit/12b404126dbe00e28ad16b4736dbe90dfda833d0))
+
+## [0.0.0-alpha.64](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.63...v0.0.0-alpha.64) (2026-09-01)
+
+
+### Features
+
+* **parser:** a refused where string names the rewrite for pandas and C connective habits ([#346](https://github.com/energy-models/math-spec/issues/346)) ([3dbd9b2](https://github.com/energy-models/math-spec/commit/3dbd9b261dd82fc5cd52924ecdd03b18ddd88c14))
+
+## [0.0.0-alpha.63](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.62...v0.0.0-alpha.63) (2026-09-01)
+
+
+### Refactoring
+
+* **language:** an operator, a declaration kind and a notation name the values they can be, rather than being a string ([#345](https://github.com/energy-models/math-spec/issues/345)) ([3f3f858](https://github.com/energy-models/math-spec/commit/3f3f8581baabc51882ad4e1d97fb774ae1944dc3))
+
+## [0.0.0-alpha.62](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.61...v0.0.0-alpha.62) (2026-09-01)
+
+
+### Bug Fixes
+
+* **language:** a declaration named what no expression could write is refused, rather than loading unreferenceable ([#340](https://github.com/energy-models/math-spec/issues/340)) ([b865bc1](https://github.com/energy-models/math-spec/commit/b865bc15fde7e5a7714cdf809f5f0b9e6e6f44e5))
+
+## [0.0.0-alpha.61](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.60...v0.0.0-alpha.61) (2026-09-01)
+
+
+### Performance
+
+* **program:** a mask walks its leaves once and every question reads that walk ([#338](https://github.com/energy-models/math-spec/issues/338)) ([337d169](https://github.com/energy-models/math-spec/commit/337d1697724980356c8d911bf21242a19a6f517a))
+
+## [0.0.0-alpha.60](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.59...v0.0.0-alpha.60) (2026-09-01)
+
+
+### Bug Fixes
+
+* **language:** the language reference states which case arms are refused, and the refusal says what actually breaks ([#336](https://github.com/energy-models/math-spec/issues/336)) ([01920d1](https://github.com/energy-models/math-spec/commit/01920d1be4f6dbd6965f6f0e7e683543384cc744))
+
+## [0.0.0-alpha.59](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.58...v0.0.0-alpha.59) (2026-09-01)
+
+
+### Bug Fixes
+
+* **parser:** a parsed expression cannot be rewritten under another pass ([#329](https://github.com/energy-models/math-spec/issues/329)) ([fcfb7b8](https://github.com/energy-models/math-spec/commit/fcfb7b8a3e2c66cd03da316994154b9c2dd493d0))
+
+## [0.0.0-alpha.58](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.57...v0.0.0-alpha.58) (2026-09-01)
+
+
+### Features
+
+* **program:** a resolved where is a first-class Mask whose leaves carry their dims, and the where grammar is package-private ([#327](https://github.com/energy-models/math-spec/issues/327)) ([53cc352](https://github.com/energy-models/math-spec/commit/53cc3522e917a5849ce3150585c2c9e05a8ea162))
+
+## [0.0.0-alpha.57](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.56...v0.0.0-alpha.57) (2026-09-01)
+
+
+### Bug Fixes
+
+* **program:** a program describes a mathematical program rather than being one, and claims neither linearity nor a storage format ([#315](https://github.com/energy-models/math-spec/issues/315)) ([5dfa6be](https://github.com/energy-models/math-spec/commit/5dfa6be817fb49999571b2fdc8b8b820371f80d0))
+
+## [0.0.0-alpha.56](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.55...v0.0.0-alpha.56) (2026-09-01)
+
+
+### Features
+
+* **program:** the conjuncts of a where mask are the program's to give, not each consumer's to re-derive ([#313](https://github.com/energy-models/math-spec/issues/313)) ([db63d3c](https://github.com/energy-models/math-spec/commit/db63d3ca90079e4031a9339ea7749c0567b31be9))
+
+## [0.0.0-alpha.55](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.54...v0.0.0-alpha.55) (2026-08-31)
+
+
+### Documentation
+
+* **ceiling:** load-time unit checking has its own refusal, where the data-prep row used to answer for it ([#272](https://github.com/energy-models/math-spec/issues/272)) ([8dfd17d](https://github.com/energy-models/math-spec/commit/8dfd17df17993f1209fe479734c3dee756fcc384))
+
+## [0.0.0-alpha.54](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.53...v0.0.0-alpha.54) (2026-08-31)
+
+
+### Documentation
+
+* drop the effects row from the PyPSA-1.3.0 parity table, a feature that release does not have ([#305](https://github.com/energy-models/math-spec/issues/305)) ([92e5ed8](https://github.com/energy-models/math-spec/commit/92e5ed84c14c59e8068a7814722950f936e2925a))
+
 ## [0.0.0-alpha.53](https://github.com/energy-models/math-spec/compare/v0.0.0-alpha.52...v0.0.0-alpha.53) (2026-08-31)
 
 

README.md

@@ -128,14 +128,15 @@ builds reads the second.
 That seam is [one page](docs/reference/language/reading.md), and it is the whole
 of it.
 
-And the same file says, in print:
+And that same `spec` says, in print — read and checked once, then printed
+three ways:
 
 ```python
 symbols = 'dispatch.symbols.yaml'  # optional: a dict, a path, or a SymbolTable
 
-ms.to_latex('dispatch.yaml', symbols=symbols)  # amsmath align
-ms.to_typst('dispatch.yaml')  # compiles without a TeX toolchain
-ms.to_markdown('dispatch.yaml')  # renders as-is on GitHub
+ms.to_latex(spec, symbols=symbols)  # amsmath align
+ms.to_typst(spec)  # compiles without a TeX toolchain
+ms.to_markdown(spec)  # renders as-is on GitHub
 ```
 
 Drop the symbol table and the same model prints as $\mathit{load}_t$,