diff --git a/publicodes/source/mecanisms/arrondi.tsx b/publicodes/source/mecanisms/arrondi.tsx
index bb527f808..0490ba20d 100644
--- a/publicodes/source/mecanisms/arrondi.tsx
+++ b/publicodes/source/mecanisms/arrondi.tsx
@@ -5,11 +5,10 @@ import { InfixMecanism } from '../components/mecanisms/common'
 import { defaultNode, evaluateNode, mergeAllMissing } from '../evaluation'
 import { simplifyNodeUnit } from '../nodeUnits'
 import { mapTemporal, pureTemporal, temporalAverage } from '../temporal'
-import { EvaluatedNode, EvaluatedRule, Evaluation } from '../types'
+import { EvaluatedNode, EvaluatedRule } from '../types'
 import { serializeUnit } from '../units'
 
 type MecanismRoundProps = {
-	nodeValue: Evaluation<number>
 	explanation: ArrondiExplanation
 }
 
@@ -18,7 +17,7 @@ type ArrondiExplanation = {
 	decimals: EvaluatedNode<string, number>
 }
 
-function MecanismRound({ nodeValue, explanation }: MecanismRoundProps) {
+function MecanismRound({ explanation }: MecanismRoundProps) {
 	return (
 		<InfixMecanism value={explanation.value}>
 			{explanation.decimals.nodeValue !== false &&
@@ -75,7 +74,7 @@ function evaluate<Names extends string>(
 	}
 }
 
-export default (recurse, k, v) => {
+export default (recurse, v) => {
 	const explanation = {
 		value: has('valeur', v) ? recurse(v['valeur']) : recurse(v),
 		decimals: has('décimales', v) ? recurse(v['décimales']) : defaultNode(0)
diff --git a/publicodes/source/mecanisms/barème.ts b/publicodes/source/mecanisms/barème.ts
index a4aa3e646..e3d76a59d 100644
--- a/publicodes/source/mecanisms/barème.ts
+++ b/publicodes/source/mecanisms/barème.ts
@@ -12,19 +12,9 @@ import {
 	evaluatePlafondUntilActiveTranche,
 	parseTranches
 } from './trancheUtils'
-import { decompose } from './utils'
-import variations from './variations'
 
-export default function parse(parse, k, v) {
-	// Barème en taux marginaux.
-
-	if (v.composantes) {
-		//mécanisme de composantes. Voir mécanismes.md/composantes
-		return decompose(parse, k, v)
-	}
-	if (v.variations) {
-		return variations(parse, k, v, true)
-	}
+// Barème en taux marginaux.
+export default function parse(parse, v) {
 	const explanation = {
 		assiette: parse(v.assiette),
 		multiplicateur: v.multiplicateur ? parse(v.multiplicateur) : defaultNode(1),
diff --git a/publicodes/source/mecanisms/condition-allof.tsx b/publicodes/source/mecanisms/condition-allof.tsx
index 9118e7972..ec13b6640 100644
--- a/publicodes/source/mecanisms/condition-allof.tsx
+++ b/publicodes/source/mecanisms/condition-allof.tsx
@@ -16,7 +16,7 @@ const evaluate = (cache, situation, parsedRules, node) => {
 	return { ...node, nodeValue, explanation, missingVariables }
 }
 
-export const mecanismAllOf = (recurse, k, v) => {
+export const mecanismAllOf = (recurse, v) => {
 	if (!is(Array, v)) throw new Error('should be array')
 	const explanation = map(recurse, v)
 	const jsx = ({ nodeValue, explanation, unit }) => (
diff --git a/publicodes/source/mecanisms/condition-oneof.tsx b/publicodes/source/mecanisms/condition-oneof.tsx
index 6ba9c90ac..6b70d99ec 100644
--- a/publicodes/source/mecanisms/condition-oneof.tsx
+++ b/publicodes/source/mecanisms/condition-oneof.tsx
@@ -26,7 +26,7 @@ const evaluate = (cache, situation, parsedRules, node) => {
 	return { ...node, nodeValue, explanation, missingVariables }
 }
 
-export const mecanismOneOf = (recurse, k, v) => {
+export const mecanismOneOf = (recurse, v) => {
 	if (!is(Array, v)) throw new Error('should be array')
 	const explanation = map(recurse, v)
 	const jsx = ({ nodeValue, explanation, unit }) => (
diff --git a/publicodes/source/mecanisms/durée.tsx b/publicodes/source/mecanisms/durée.tsx
index ca3e8fffa..2492858a2 100644
--- a/publicodes/source/mecanisms/durée.tsx
+++ b/publicodes/source/mecanisms/durée.tsx
@@ -69,7 +69,7 @@ const evaluate = (cache, situation, parsedRules, node) => {
 	}
 }
 
-export default (recurse, k, v) => {
+export default (recurse, v) => {
 	const explanation = parseObject(recurse, objectShape, v)
 
 	return {
diff --git a/publicodes/source/mecanisms/encadrement.tsx b/publicodes/source/mecanisms/encadrement.tsx
index a7ab07aa2..b19ab57ef 100644
--- a/publicodes/source/mecanisms/encadrement.tsx
+++ b/publicodes/source/mecanisms/encadrement.tsx
@@ -82,7 +82,7 @@ const evaluate = evaluateObject(
 	}
 )
 
-export default (recurse, k, v) => {
+export default (recurse, v) => {
 	const explanation = parseObject(recurse, objectShape, v)
 
 	return {
diff --git a/publicodes/source/mecanisms/grille.ts b/publicodes/source/mecanisms/grille.ts
index cedc5c939..3faa115cd 100644
--- a/publicodes/source/mecanisms/grille.ts
+++ b/publicodes/source/mecanisms/grille.ts
@@ -1,8 +1,6 @@
 import { lensPath, over } from 'ramda'
 import grille from '../components/mecanisms/Grille'
 import { defaultNode, evaluateNode, mergeAllMissing } from '../evaluation'
-import { decompose } from '../mecanisms/utils'
-import variations from '../mecanisms/variations'
 import {
 	liftTemporal2,
 	liftTemporalNode,
@@ -15,14 +13,7 @@ import {
 	parseTranches
 } from './trancheUtils'
 
-export default function parse(parse, k, v) {
-	if (v.composantes) {
-		//mécanisme de composantes. Voir mécanismes.md/composantes
-		return decompose(parse, k, v)
-	}
-	if (v.variations) {
-		return variations(parse, k, v, true)
-	}
+export default function parse(parse, v) {
 	const defaultUnit = v['unité'] && parseUnit(v['unité'])
 	const explanation = {
 		assiette: parse(v.assiette),
diff --git a/publicodes/source/mecanisms/inversion.ts b/publicodes/source/mecanisms/inversion.ts
index d6fe7283c..7d46f3ceb 100644
--- a/publicodes/source/mecanisms/inversion.ts
+++ b/publicodes/source/mecanisms/inversion.ts
@@ -86,7 +86,7 @@ export const evaluateInversion = (oldCache, situation, parsedRules, node) => {
 	}
 }
 
-export const mecanismInversion = dottedName => (recurse, k, v) => {
+export const mecanismInversion = dottedName => (recurse, v) => {
 	if (!v.avec) {
 		throw new Error(
 			"Une formule d'inversion doit préciser _avec_ quoi on peut inverser la variable"
diff --git a/publicodes/source/mecanisms/max.tsx b/publicodes/source/mecanisms/max.tsx
index ec5d1f1d6..0f11d5c73 100644
--- a/publicodes/source/mecanisms/max.tsx
+++ b/publicodes/source/mecanisms/max.tsx
@@ -2,7 +2,7 @@ import React from 'react'
 import { Mecanism } from '../components/mecanisms/common'
 import { evaluateArray, makeJsx } from '../evaluation'
 
-export const mecanismMax = (recurse, k, v) => {
+export const mecanismMax = (recurse, v) => {
 	const explanation = v.map(recurse)
 
 	const max = (a, b) => {
diff --git a/publicodes/source/mecanisms/min.tsx b/publicodes/source/mecanisms/min.tsx
index 0a8b9b0fc..fdd985ec4 100644
--- a/publicodes/source/mecanisms/min.tsx
+++ b/publicodes/source/mecanisms/min.tsx
@@ -3,7 +3,7 @@ import React from 'react'
 import { Mecanism } from '../components/mecanisms/common'
 import { evaluateArray, makeJsx } from '../evaluation'
 
-export const mecanismMin = (recurse, k, v) => {
+export const mecanismMin = (recurse, v) => {
 	const explanation = v.map(recurse)
 	const evaluate = evaluateArray(min, Infinity)
 	const jsx = ({ nodeValue, explanation, unit }) => (
diff --git a/publicodes/source/mecanisms/one-possibility.tsx b/publicodes/source/mecanisms/one-possibility.tsx
index 353629014..2e00a1816 100644
--- a/publicodes/source/mecanisms/one-possibility.tsx
+++ b/publicodes/source/mecanisms/one-possibility.tsx
@@ -1,5 +1,5 @@
 // TODO : This isn't a real mecanism, cf. #963
-export const mecanismOnePossibility = dottedName => (recurse, k, v) => ({
+export const mecanismOnePossibility = dottedName => (recurse, v) => ({
 	...v,
 	'une possibilité': 'oui',
 	evaluate: (cache, situation, parsedRules, node) => ({
diff --git a/publicodes/source/mecanisms/operation.tsx b/publicodes/source/mecanisms/operation.tsx
index 15517cd00..1a48a979c 100644
--- a/publicodes/source/mecanisms/operation.tsx
+++ b/publicodes/source/mecanisms/operation.tsx
@@ -8,7 +8,7 @@ import { inferUnit, serializeUnit } from '../units'
 import { curry, map } from 'ramda'
 import React from 'react'
 
-export default (k, operatorFunction, symbol) => (recurse, k, v) => {
+export default (k, operatorFunction, symbol) => (recurse, v) => {
 	const evaluate = (cache, situation, parsedRules, node) => {
 		const explanation = map(
 			curry(evaluateNode)(cache, situation, parsedRules),
diff --git a/publicodes/source/mecanisms/product.tsx b/publicodes/source/mecanisms/product.tsx
index e7a96ceb1..2ef5d01d1 100644
--- a/publicodes/source/mecanisms/product.tsx
+++ b/publicodes/source/mecanisms/product.tsx
@@ -1,19 +1,10 @@
 import Product from '../components/mecanisms/Product'
 import { typeWarning } from '../error'
 import { defaultNode, evaluateObject, parseObject } from '../evaluation'
-import { decompose } from './utils'
-import variations from './variations'
 import { convertNodeToUnit } from '../nodeUnits'
 import { areUnitConvertible, convertUnit, inferUnit } from '../units'
 
-export const mecanismProduct = (recurse, k, v) => {
-	if (v.composantes) {
-		//mécanisme de composantes. Voir mécanismes.md/composantes
-		return decompose(recurse, k, v)
-	}
-	if (v.variations) {
-		return variations(recurse, k, v, true)
-	}
+export const mecanismProduct = (recurse, v) => {
 	const objectShape = {
 		assiette: false,
 		taux: defaultNode(1),
diff --git a/publicodes/source/mecanisms/recalcul.ts b/publicodes/source/mecanisms/recalcul.ts
index bfd983284..4cace26b9 100644
--- a/publicodes/source/mecanisms/recalcul.ts
+++ b/publicodes/source/mecanisms/recalcul.ts
@@ -45,7 +45,7 @@ const evaluateRecalcul = (cache, situation, parsedRules, node) => {
 	}
 }
 
-export const mecanismRecalcul = dottedNameContext => (recurse, k, v) => {
+export const mecanismRecalcul = dottedNameContext => (recurse, v) => {
 	const amendedSituation = Object.keys(v.avec).map(dottedName => [
 		recurse(dottedName),
 		recurse(v.avec[dottedName])
diff --git a/publicodes/source/mecanisms/reduction.ts b/publicodes/source/mecanisms/reduction.ts
index 1d54848a0..238a3efed 100644
--- a/publicodes/source/mecanisms/reduction.ts
+++ b/publicodes/source/mecanisms/reduction.ts
@@ -5,7 +5,7 @@ import { defaultNode, evaluateObject, parseObject } from '../evaluation'
 import { convertNodeToUnit } from '../nodeUnits'
 import { parseUnit, serializeUnit } from '../units'
 
-export const mecanismReduction = (recurse, k, v) => {
+export const mecanismReduction = (recurse, v) => {
 	const objectShape = {
 		assiette: false,
 		abattement: defaultNode(0),
diff --git a/publicodes/source/mecanisms/régularisation.ts b/publicodes/source/mecanisms/régularisation.ts
index a6db5006f..783ad1423 100644
--- a/publicodes/source/mecanisms/régularisation.ts
+++ b/publicodes/source/mecanisms/régularisation.ts
@@ -20,7 +20,7 @@ function stripTemporalTransform(node) {
 	}
 	return stripTemporalTransform(node.explanation.value)
 }
-export default function parse<Name extends string>(parse, k, v) {
+export default function parse<Name extends string>(parse, v) {
 	const rule = parse(v.règle)
 	if (!v['valeurs cumulées']) {
 		throw new Error(
diff --git a/publicodes/source/mecanisms/sum.tsx b/publicodes/source/mecanisms/sum.tsx
index 12080892b..f6bf4bf7c 100644
--- a/publicodes/source/mecanisms/sum.tsx
+++ b/publicodes/source/mecanisms/sum.tsx
@@ -7,7 +7,7 @@ const evaluate = evaluateArray(
 	false
 )
 
-export const mecanismSum = (recurse, k, v) => {
+export const mecanismSum = (recurse, v) => {
 	const explanation = v.map(recurse)
 	return {
 		evaluate,
diff --git a/publicodes/source/mecanisms/synchronisation.tsx b/publicodes/source/mecanisms/synchronisation.tsx
index 3da9cc752..033b37502 100644
--- a/publicodes/source/mecanisms/synchronisation.tsx
+++ b/publicodes/source/mecanisms/synchronisation.tsx
@@ -33,7 +33,7 @@ const evaluate = (cache, situation, parsedRules, node) => {
 	return { ...node, nodeValue: safeNodeValue, explanation, missingVariables }
 }
 
-export const mecanismSynchronisation = (recurse, k, v) => {
+export const mecanismSynchronisation = (recurse, v) => {
 	return {
 		explanation: { ...v, API: recurse(v.API) },
 		evaluate,
diff --git a/publicodes/source/mecanisms/tauxProgressif.ts b/publicodes/source/mecanisms/tauxProgressif.ts
index ace9738d2..287bafb1e 100644
--- a/publicodes/source/mecanisms/tauxProgressif.ts
+++ b/publicodes/source/mecanisms/tauxProgressif.ts
@@ -1,6 +1,4 @@
 import { defaultNode, evaluateNode, mergeAllMissing } from '../evaluation'
-import { decompose } from './utils'
-import variations from './variations'
 import tauxProgressif from '../components/mecanisms/TauxProgressif'
 import { convertNodeToUnit } from '../nodeUnits'
 import { parseUnit } from '../units'
@@ -9,15 +7,7 @@ import {
 	parseTranches
 } from './trancheUtils'
 
-export default function parse(parse, k, v) {
-	if (v.composantes) {
-		//mécanisme de composantes. Voir mécanismes.md/composantes
-		return decompose(parse, k, v)
-	}
-	if (v.variations) {
-		return variations(parse, k, v, true)
-	}
-
+export default function parse(parse, v) {
 	const explanation = {
 		assiette: parse(v.assiette),
 		multiplicateur: v.multiplicateur ? parse(v.multiplicateur) : defaultNode(1),
diff --git a/publicodes/source/mecanisms/variableTemporelle.ts b/publicodes/source/mecanisms/variableTemporelle.ts
index b1a315af0..9a4398c8b 100644
--- a/publicodes/source/mecanisms/variableTemporelle.ts
+++ b/publicodes/source/mecanisms/variableTemporelle.ts
@@ -46,7 +46,7 @@ function evaluate(
 	}
 }
 
-export default function parseVariableTemporelle(parse, __, v: any) {
+export default function parseVariableTemporelle(parse, v) {
 	const explanation = parse(v.explanation)
 	return {
 		evaluate,
diff --git a/publicodes/source/mecanisms/variations.ts b/publicodes/source/mecanisms/variations.ts
index e854fa5b3..1754f8137 100644
--- a/publicodes/source/mecanisms/variations.ts
+++ b/publicodes/source/mecanisms/variations.ts
@@ -12,15 +12,12 @@ import {
 import { inferUnit } from '../units'
 import { mergeAllMissing } from './../evaluation'
 
-/* @devariate = true => This function will produce variations of a same mecanism (e.g. product) that share some common properties */
-export default function parse(recurse, k, v, devariate) {
-	const explanation = devariate
-		? devariateExplanation(recurse, k, v)
-		: v.map(({ si, alors, sinon }) =>
-				sinon !== undefined
-					? { consequence: recurse(sinon), condition: defaultNode(true) }
-					: { consequence: recurse(alors), condition: recurse(si) }
-		  )
+export default function parse(recurse, v) {
+	const explanation = v.map(({ si, alors, sinon }) =>
+		sinon !== undefined
+			? { consequence: recurse(sinon), condition: defaultNode(true) }
+			: { consequence: recurse(alors), condition: recurse(si) }
+	)
 
 	// TODO - find an appropriate representation
 	return {
@@ -36,6 +33,23 @@ export default function parse(recurse, k, v, devariate) {
 		)
 	}
 }
+
+export function devariate(recurse, k, v) {
+	const explanation = devariateExplanation(recurse, k, v)
+	return {
+		explanation,
+		evaluate,
+		jsx: Variations,
+		category: 'mecanism',
+		name: 'variations',
+		type: 'numeric',
+		unit: inferUnit(
+			'+',
+			explanation.map(r => r.consequence.unit)
+		)
+	}
+}
+
 type Variation =
 	| {
 			si: any
@@ -44,7 +58,7 @@ type Variation =
 	| {
 			sinon: object
 	  }
-export const devariateExplanation = (
+const devariateExplanation = (
 	recurse,
 	mecanismKey,
 	v: { variations: Array<Variation> }
diff --git a/publicodes/source/parse.tsx b/publicodes/source/parse.tsx
index 6c3fe1042..968336d59 100644
--- a/publicodes/source/parse.tsx
+++ b/publicodes/source/parse.tsx
@@ -1,7 +1,6 @@
 // This should be the new way to implement mecanisms
 // In a specific file
 // TODO import them automatically
-// TODO convert the legacy functions to new files
 import mecanismRound, { unchainRoundMecanism } from './mecanisms/arrondi'
 import barème from './mecanisms/barème'
 import durée from './mecanisms/durée'
@@ -11,7 +10,7 @@ import operation from './mecanisms/operation'
 import régularisation from './mecanisms/régularisation'
 import tauxProgressif from './mecanisms/tauxProgressif'
 import variableTemporelle from './mecanisms/variableTemporelle'
-import variations from './mecanisms/variations'
+import variations, { devariate } from './mecanisms/variations'
 import { Grammar, Parser } from 'nearley'
 import {
 	add,
@@ -43,6 +42,7 @@ import { mecanismSynchronisation } from './mecanisms/synchronisation'
 import { mecanismRecalcul } from './mecanisms/recalcul'
 import { parseReferenceTransforms } from './parseReference'
 import { EvaluatedRule } from './types'
+import { decompose } from './mecanisms/utils'
 
 export const parse = (rules, rule, parsedRules) => rawNode => {
 	if (rawNode == null) {
@@ -146,6 +146,7 @@ Cela vient probablement d'une erreur dans l'indentation
 	}
 
 	const parseFn = parseFunctions[mecanismName]
+
 	if (!parseFn) {
 		syntaxError(
 			rule.dottedName,
@@ -155,7 +156,15 @@ Vérifiez qu'il n'y ait pas d'erreur dans l'orthographe du nom.`
 		)
 	}
 	try {
-		return parseFn(parse(rules, rule, parsedRules), mecanismName, values)
+		const recurse = parse(rules, rule, parsedRules)
+		// Mécanisme de composantes. Voir mécanismes.md/composantes
+		if (values?.composantes) {
+			return decompose(recurse, mecanismName, values)
+		}
+		if (values?.variations) {
+			return devariate(recurse, mecanismName, values)
+		}
+		return parseFn(recurse, values)
 	} catch (e) {
 		if (e instanceof EngineError) {
 			throw e
@@ -232,8 +241,8 @@ const statelessParseFunction = {
 	allègement: mecanismReduction,
 	variations,
 	synchronisation: mecanismSynchronisation,
-	valeur: (recurse, __, v) => recurse(v),
-	constant: (_, __, v) => ({
+	valeur: (recurse, v) => recurse(v),
+	constant: (_, v) => ({
 		type: v.type,
 		constant: true,
 		nodeValue: v.nodeValue,