diff --git a/packages/squiggle-lang/package.json b/packages/squiggle-lang/package.json
index 03c7517a..bf76709a 100644
--- a/packages/squiggle-lang/package.json
+++ b/packages/squiggle-lang/package.json
@@ -56,6 +56,7 @@
     "lodash": "^4.17.21",
     "moduleserve": "^0.9.1",
     "nyc": "^15.1.0",
+    "peggy": "^1.2.0",
     "reanalyze": "^2.19.0",
     "rescript-fast-check": "^1.1.1",
     "ts-jest": "^27.1.4",
diff --git a/yarn.lock b/yarn.lock
index 9666fb0e..a9c6c487 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4477,7 +4477,7 @@
   dependencies:
     "@types/react" "*"
 
-"@types/react@*", "@types/react@^18.0.1", "@types/react@^18.0.9":
+"@types/react@*", "@types/react@^18.0.9":
   version "18.0.9"
   resolved "https://registry.yarnpkg.com/@types/react/-/react-18.0.9.tgz#d6712a38bd6cd83469603e7359511126f122e878"
   integrity sha512-9bjbg1hJHUm4De19L1cHiW0Jvx3geel6Qczhjd0qY5VKVE2X5+x77YxAepuCwVh4vrgZJdgEJw48zrhRIeF4Nw==
@@ -13225,6 +13225,11 @@ pdfast@^0.2.0:
   resolved "https://registry.yarnpkg.com/pdfast/-/pdfast-0.2.0.tgz#8cbc556e1bf2522177787c0de2e0d4373ba885c9"
   integrity sha1-jLxVbhvyUiF3eHwN4uDUNzuohck=
 
+peggy@^1.2.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/peggy/-/peggy-1.2.0.tgz#657ba45900cbef1dc9f52356704bdbb193c2021c"
+  integrity sha512-PQ+NKpAobImfMprYQtc4Egmyi29bidRGEX0kKjCU5uuW09s0Cthwqhfy7mLkwcB4VcgacE5L/ZjruD/kOPCUUw==
+
 performance-now@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/performance-now/-/performance-now-2.1.0.tgz#6309f4e0e5fa913ec1c69307ae364b4b377c9e7b"
@@ -14678,7 +14683,7 @@ react-vega@^7.5.1:
     prop-types "^15.8.1"
     vega-embed "^6.5.1"
 
-react@^18.0.0, react@^18.1.0:
+react@^18.1.0:
   version "18.1.0"
   resolved "https://registry.yarnpkg.com/react/-/react-18.1.0.tgz#6f8620382decb17fdc5cc223a115e2adbf104890"
   integrity sha512-4oL8ivCz5ZEPyclFQXaNksK3adutVS8l2xzZU0cqEFrE9Sb7fC0EFK5uEk74wIreL1DERyjvsU915j1pcT2uEQ==