diff --git a/src/webgl/ShaderGenerator.js b/src/webgl/ShaderGenerator.js
index d029ed44ef..a4ecb7c9ae 100644
--- a/src/webgl/ShaderGenerator.js
+++ b/src/webgl/ShaderGenerator.js
@@ -19,7 +19,9 @@ function shadergenerator(p5, fn) {
     if (shaderModifier instanceof Function) {
       let generatorFunction;
       if (options.parser) {
-        const sourceString = shaderModifier.toString()
+        // #7955 Wrap function declaration code in brackets so anonymous functions are not top level statements, which causes an error in acorn when parsing
+        // https://github.com/acornjs/acorn/issues/1385
+        const sourceString = `(${shaderModifier.toString()})`;
         const ast = parse(sourceString, {
           ecmaVersion: 2021,
           locations: options.srcLocations
diff --git a/test/unit/webgl/p5.Shader.js b/test/unit/webgl/p5.Shader.js
index 00d4d00847..8567280e38 100644
--- a/test/unit/webgl/p5.Shader.js
+++ b/test/unit/webgl/p5.Shader.js
@@ -324,6 +324,11 @@ suite('p5.Shader', function() {
         expect(modified.fragSrc()).not.to.match(/#define AUGMENTED_HOOK_getVertexColor/);
       });
 
+      test('anonymous function shaderModifier does not throw when parsed', function() {
+        const callModify = () => myShader.modify(function() {});
+        expect(callModify).not.toThrowError();
+      });
+
       test('filled hooks do have an AUGMENTED_HOOK define', function() {
         const modified = myShader.modify({
           'vec4 getVertexColor': `(vec4 c) {