FE-514: Compile TypeScript expressions to SymPy by kube · Pull Request #8541 · hashintel/hash

kube · 2026-03-13T01:34:19Z

🌟 What is the purpose of this PR?

Adds the ability to compile Petrinaut's TypeScript expressions (rate laws, guard conditions, dynamics) into SymPy Python code — enabling interoperability with external scientific computing tools (TOPOS, Coherence Research). This is a demo-quality implementation proving the concept and establishing the TS→SymPy mapping.

🔗 Related links

FE-514: Compile TypeScript expressions to SymPy (internal)

🔍 What does this change?

compile-to-sympy.ts — AST-walking compiler that parses TypeScript expressions and emits SymPy equivalents. Supports arithmetic, comparisons, logical operators, ternary→Piecewise, Math.* functions/constants, Distribution.*, token/parameter access, object literals, const bindings, and type assertion unwrapping. Rejects unsupported syntax with positioned error diagnostics (start/length).
compile-to-sympy.test.ts — 51 tests covering all supported syntax, real-world expressions (SIR model, orbital dynamics, transition kernels), and error cases with position assertions.
checker.ts — Integrates SymPy compilation into the LSP checker. Runs compileToSymPy on all differential equations, transition lambdas, and transition kernels. Failures surface as warnings (code 99000) with accurate source positions in the Diagnostics tab.
export-sympy.ts — New export function that converts all model expressions to SymPy and produces a JSON file containing both the original SDCPN and a sympy_expressions array.
editor-view.tsx — Adds "JSON with SymPy expressions" to the Export submenu.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

does not modify any publishable blocks or libraries, or modifications do not need publishing

📜 Does this require a change to the docs?

The changes in this PR:

are internal and do not require a docs change

🕸️ Does this require a change to the Turbo Graph?

The changes in this PR:

do not affect the execution graph

⚠️ Known issues

This is a restricted subset compiler — not all valid TypeScript will produce SymPy output. Unsupported constructs (control flow, let, arbitrary function calls) are rejected with warnings rather than errors, since the TS code itself is still valid.

🐾 Next steps

Python language support (H-6323) would complement this by providing the runtime for SymPy expressions.

🛡 What tests cover this?

51 unit tests in compile-to-sympy.test.ts covering basic expressions, parameter/token access, all operators, Math functions, distributions, block bodies, real-world expressions, and error positioning.

❓ How to test this?

Checkout the branch
Open Petrinaut editor, load an example model (e.g. SIR Model, Satellites)
Check the Diagnostics tab for SymPy warnings on any unsupported expressions
Use Export → "JSON with SymPy expressions" and verify the output contains sympy_expressions with converted code

vercel · 2026-03-13T01:34:23Z

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kube · 2026-03-13T01:34:32Z

FE-514: Add SymPy → JavaScript compilation pipeline via Pyodide #8548
FE-514: Compile TypeScript expressions to SymPy #8541 👈 (View in Graphite)
H-6324: Migrate petrinaut to oxlint and verify React Compiler #8539 : 4 other dependent PRs (#8532 , #8537 , #8549 and 1 other)
main

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cursor · 2026-03-13T01:35:25Z

PR Summary

Medium Risk
Introduces a new AST-based compiler and feeds its failures into the LSP diagnostics pipeline; because these warnings are added to itemDiagnostics, they may affect overall isValid and reviewer expectations around “valid” nets.

Overview
Adds a new compileToSymPy pipeline that parses SDCPN transition/differential-equation TypeScript snippets and converts a restricted subset of expressions into SymPy code, with positional error reporting and extensive unit tests.

Integrates SymPy compilation into checkSDCPN by appending synthetic warning diagnostics (code: 99000) for any expressions that can’t be converted.

Extends the editor export menu with “JSON with SymPy expressions”, generating an export that embeds per-expression SymPy output (or conversion errors) alongside the original SDCPN model.

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cursor · 2026-03-13T01:39:00Z

libs/@hashintel/petrinaut/src/lsp/lib/checker.ts


+  // Run SymPy compilation checks on all code expressions
+  checkSymPyCompilation(sdcpn, itemDiagnostics);
+


SymPy warnings incorrectly invalidate the SDCPN check result

High Severity

checkSymPyCompilation appends SymPy failure diagnostics (intentionally marked as warnings, category 0) into itemDiagnostics, but isValid is computed as itemDiagnostics.length === 0. This means any code that can't be converted to SymPy — such as transition kernels returning array literals like [{ x: 1 }], which aren't handled by compile-to-sympy.ts — will cause the entire SDCPN to be reported as invalid, even though the TypeScript is perfectly valid. The comment on makeSymPyDiagnostic explicitly states these are "informational" and "the TypeScript code may still be valid," contradicting the effect on isValid.

Additional Locations (1)

libs/@hashintel/petrinaut/src/lsp/lib/checker.ts#L43-L52

cursor · 2026-03-13T01:39:00Z

libs/@hashintel/petrinaut/src/simulation/simulator/compile-to-sympy.ts

+    }
+  }
+
+  const exportExpr = exportAssignment!.expression;


Null dereference when fallback export search succeeds

Medium Severity

When exportAssignment is undefined (first find failed), the fallback search at line 130 can match an export = statement (since it doesn't filter by !isExportEquals). If exportDefault is found, the code falls through the if block and reaches exportAssignment!.expression on line 142, but exportAssignment is still undefined, causing a runtime crash. The fallback block never reassigns exportAssignment, so the non-null assertion is incorrect on that path.

graphite-app · 2026-03-13T01:39:07Z

libs/@hashintel/petrinaut/src/simulation/simulator/compile-to-sympy.ts

+  if (!exportAssignment) {
+    // Try export default as ExpressionStatement pattern
+    const exportDefault = sourceFile.statements.find((stmt) => {
+      if (ts.isExportAssignment(stmt)) {
+        return true;
+      }
+      // Handle "export default X(...)" which parses as ExportAssignment
+      return false;
+    });
+    if (!exportDefault) {
+      return errNoPos("No default export found");
+    }
+  }
+
+  const exportExpr = exportAssignment!.expression;


Critical null reference bug. If exportAssignment is null (line 128), the code enters the fallback logic (lines 129-136) to find exportDefault. However, line 142 unconditionally accesses exportAssignment!.expression which will be null, causing a runtime error.

Fix: The fallback logic appears incomplete. After finding exportDefault, it should be assigned to a variable and used instead of exportAssignment. The code should be:

let exportAssignment = sourceFile.statements.find( (stmt): stmt is ts.ExportAssignment => ts.isExportAssignment(stmt) && !stmt.isExportEquals, ); if (!exportAssignment) { return errNoPos("No default export found"); } const exportExpr = exportAssignment.expression;

The fallback logic (lines 129-136) appears to be dead code that doesn't actually change the outcome and should be removed.

Suggested change

if (!exportAssignment) {

// Try export default as ExpressionStatement pattern

const exportDefault = sourceFile.statements.find((stmt) => {

if (ts.isExportAssignment(stmt)) {

return true;

}

// Handle "export default X(...)" which parses as ExportAssignment

return false;

});

if (!exportDefault) {

return errNoPos("No default export found");

}

}

const exportExpr = exportAssignment!.expression;

const exportAssignment = sourceFile.statements.find(

(stmt): stmt is ts.ExportAssignment =>

ts.isExportAssignment(stmt) && !stmt.isExportEquals,

);

if (!exportAssignment) {

return errNoPos("No default export found");

}

const exportExpr = exportAssignment.expression;

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augmentcode · 2026-03-13T01:39:59Z

🤖 Augment PR Summary

Summary: This PR introduces SymPy compilation support for Petrinaut code snippets and surfaces conversion issues as diagnostics, plus adds an export option that includes SymPy-rendered expressions.

Changes:

Added a TypeScript-AST based compiler (compileToSymPy) that converts a restricted subset of Petrinaut TS expressions into SymPy/Python code.
Added context builders for transitions and differential equations to distinguish parameters/token fields during compilation.
Integrated SymPy compilation into the LSP checker to emit warning diagnostics when code is valid TS but not convertible to SymPy.
Added a new “JSON with SymPy expressions” export option in the editor.
Implemented exportWithSymPy to export the SDCPN alongside a sympy_expressions section containing compiled code/errors.
Added extensive Vitest coverage for supported/unsupported SymPy compilation cases and error positioning.

Technical Notes: Diagnostics are generated as synthetic ts.Diagnostics (custom code 99000) and are mapped to LSP warnings using existing serialization utilities.

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Review completed. 6 suggestions posted.

Comment augment review to trigger a new review at any time.

augmentcode · 2026-03-13T01:40:00Z

libs/@hashintel/petrinaut/src/lsp/lib/checker.ts

+      );
+    }
+
+    const kernelCtx = buildContextForTransition(


checkSymPyCompilation() compiles transitionKernelCode for every transition, but the TS checker explicitly skips kernel validation when there are no coloured output places; this will likely produce noisy SymPy warnings (and change isValid) for kernels that are effectively unused.

Severity: medium

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augmentcode · 2026-03-13T01:40:00Z

libs/@hashintel/petrinaut/src/lsp/lib/checker.ts

+  checkSymPyCompilation(sdcpn, itemDiagnostics);
+
  return {
    isValid: itemDiagnostics.length === 0,


isValid: itemDiagnostics.length === 0 now treats SymPy compilation failures (which are emitted as warnings) as making the SDCPN invalid, which seems to contradict the “informational” intent in makeSymPyDiagnostic() and will also break callers/tests that expect warnings not to invalidate the model.

Severity: high

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augmentcode · 2026-03-13T01:40:00Z

libs/@hashintel/petrinaut/src/simulation/simulator/compile-to-sympy.ts

+    }
+  }
+
+  const exportExpr = exportAssignment!.expression;


If exportAssignment is not found but an ExportAssignment with isExportEquals is present, the current flow falls through and then dereferences exportAssignment!, which will throw at runtime instead of returning a clean { ok: false } result.

Severity: medium

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augmentcode · 2026-03-13T01:40:00Z

libs/@hashintel/petrinaut/src/simulation/simulator/compile-to-sympy.ts

+      );
+      if (!result.ok) return result;
+      lines.push(result.sympyCode);
+    } else if (ts.isExpressionStatement(stmt)) {


compileBlock() currently skips all ExpressionStatements under the assumption they are comments, but comments aren’t represented as expression statements in the TS AST; this can silently ignore real statements like console.log(...) and incorrectly report a successful SymPy compilation.

Severity: medium

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augmentcode · 2026-03-13T01:40:00Z

libs/@hashintel/petrinaut/src/simulation/simulator/compile-to-sympy.ts

+          sourceFile,
+        );
+      }
+      const key = prop.name.getText(sourceFile);


For object literals, const key = prop.name.getText(sourceFile) will include quotes for string-literal keys (e.g. "Place A"), and then the output wraps it in quotes again ('"Place A"'), producing incorrect SymPy/Python dict keys.

Severity: medium

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augmentcode · 2026-03-13T01:40:00Z

libs/@hashintel/petrinaut/src/views/Editor/lib/export-sympy.ts

+    });
+  }
+
+  const exportData = {


exportData spreads ...petriNetDefinition after setting title/sympy_expressions; since imported JSON can carry extra fields (e.g. exporting then re-importing), the spread can overwrite these new fields and drop the freshly-compiled SymPy output.

Severity: medium

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Integrate compileToSymPy into the LSP checker so SymPy-incompatible expressions surface as warnings in the Diagnostics tab with accurate source positions. Add "JSON with SymPy expressions" export menu entry. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Boolean(expr) maps to sp.Ne(expr, 0) matching JS truthiness semantics. Number(expr) passes through as identity in symbolic math context. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Maps TypeScript array literals to Python lists, enabling transition kernels that return arrays of token objects to compile to SymPy. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Compiles tokens.map(callback) to [body for _iter in collection], handling both destructured ({ x, y }) and simple (token) parameters. Enables dynamics expressions that iterate over token arrays. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…ompiler Only const is allowed — both let and var are now rejected. Standalone expression statements (not assigned or returned) produce a diagnostic. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Refactors the compiler into two layers: TypeScript → Expression IR (JSON) → SymPy. The IR captures bindings, expressions, distributions, and derived distributions as a typed JSON AST, enabling future backends beyond SymPy. Key changes: - expression-ir.ts: 18 IR node types (number, symbol, parameter, tokenAccess, binary, unary, call, distribution, derivedDistribution, piecewise, etc.) - compile-to-ir.ts: TS→IR compiler with scope tracking for distribution bindings and support for Distribution.map() as derived distributions - ir-to-sympy.ts: IR→SymPy converter with let-binding inlining - compile-to-sympy.ts: thin wrapper composing the two layers - checker.ts: separate SymPy warnings from TS errors so isValid only reflects TypeScript validity; skip kernel checks for uncoloured outputs - Storybook playground for live TS→IR visualization Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Reorganize into src/expression/{ts-to-ir,ir-to-sympy} and remove the compile-to-sympy convenience wrapper. The LSP checker now uses compileToIR directly and reports "Invalid expression" instead of "SymPy" in diagnostics. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Add a `showExpressionOutput` user setting (default: false) with a toggle in the viewport settings dialog. When enabled, a resizable split panel appears below the Lambda and Transition Results code editors showing the compiled output. A floating format selector allows switching between expression IR (JSON) and SymPy (Python). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- Rewrite SymPy emitter to produce clean Python: explicit `from X import Y` imports (no `sp.` prefix), hoisted named distributions from let-bindings, inline anonymous distributions, `return` statement, and auto-indented dicts/lists when >80 chars. DerivedDistribution replaced with direct symbolic substitution. - Add OCaml backend (ir-to-ocaml) with Float operators, let-in bindings, Distribution functions, auto-indented records/lists, and direct distribution substitution (no Distribution.map wrapper). - Add Lean 4 backend (ir-to-lean) with Mathlib imports, Real.cos/sin/sqrt, Unicode operators (≤, ≥, ≠, ∧, ∨, ¬), gaussianReal/uniformOn distributions, and ℝ type annotations on let-bindings. - Wire all four targets (IR, SymPy, OCaml, Lean) into the expression output panel selector. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Import Python and F# language contributions in the Monaco provider. Map output formats to Monaco languages: JSON for IR, Python for SymPy, F# for OCaml and Lean. Use key-based remount to ensure language switches correctly when the user changes format. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Extract shared `formatIRResult` and `useCompileToOutput` helpers from the expression output hook. Add `useDiffEqExpressionOutput` for differential equations using `buildContextForDifferentialEquation`. Show the same resizable split panel with format selector in the differential equation Code section when the setting is enabled. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Destructured .map(({ x, y }) => ...) now emits propertyAccess nodes (token.x, token.y) instead of prefixed symbols (_iter_x, _iter_y). The iteration variable is derived from the collection name by singularizing it (tokens → token). Simple .map((token) => ...) uses the user's parameter name directly. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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kube changed the title ~~FE-514: Add SymPy compilation diagnostics and export option~~ FE-514: Compile TypeScript expressions to SymPy Mar 13, 2026

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This was referenced Mar 15, 2026

FE-518: Add Storybook and update build/lint setup for refractive #8549

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Enable React Compiler for SimulationTimeline chart components #8550

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FE-43: Add alternative OBB and polar distance map filters for refractive #8552

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FE-514: Support Boolean() and Number() global calls in SymPy compiler

f9c6271

Boolean(expr) maps to sp.Ne(expr, 0) matching JS truthiness semantics. Number(expr) passes through as identity in symbolic math context. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

FE-514: Support array literal expressions in SymPy compiler

1470a08

Maps TypeScript array literals to Python lists, enabling transition kernels that return arrays of token objects to compile to SymPy. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

FE-514: Reject var declarations and standalone expressions in SymPy c…

1b64b08

…ompiler Only const is allowed — both let and var are now rejected. Standalone expression statements (not assigned or returned) produce a diagnostic. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

kube force-pushed the cf/fe-514-compile-typescript-expressions-to-sympy branch from 70fa667 to b8e3990 Compare March 18, 2026 19:32

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FE-514: Mark expression output setting as experimental

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		// Run SymPy compilation checks on all code expressions
		checkSymPyCompilation(sdcpn, itemDiagnostics);

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🌟 What is the purpose of this PR?

🔗 Related links

🔍 What does this change?

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

📜 Does this require a change to the docs?

🕸️ Does this require a change to the Turbo Graph?

⚠️ Known issues

🐾 Next steps

🛡 What tests cover this?

❓ How to test this?

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SymPy warnings incorrectly invalidate the SDCPN check result

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Null dereference when fallback export search succeeds

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