diff --git a/include/tree_sitter/runtime.h b/include/tree_sitter/runtime.h
index 1b2c90b6..e2a1dd3f 100644
--- a/include/tree_sitter/runtime.h
+++ b/include/tree_sitter/runtime.h
@@ -19,8 +19,8 @@ typedef enum {
 
 typedef struct {
   void *payload;
-  const char *(*read_fn)(void *payload, size_t *bytes_read);
-  int (*seek_fn)(void *payload, size_t character, size_t byte);
+  const char *(*read)(void *payload, size_t *bytes_read);
+  int (*seek)(void *payload, size_t character_index, size_t byte_index);
   TSInputEncoding encoding;
 } TSInput;
 
diff --git a/spec/helpers/spy_input.cc b/spec/helpers/spy_input.cc
index 3968bcc2..d5d4bf96 100644
--- a/spec/helpers/spy_input.cc
+++ b/spec/helpers/spy_input.cc
@@ -63,8 +63,8 @@ TSInput SpyInput::input() {
   TSInput result;
   result.payload = this;
   result.encoding = encoding;
-  result.seek_fn = seek;
-  result.read_fn = read;
+  result.seek = seek;
+  result.read = read;
   return result;
 }
 
diff --git a/spec/runtime/document_spec.cc b/spec/runtime/document_spec.cc
index 8b50e33b..ec479b4e 100644
--- a/spec/runtime/document_spec.cc
+++ b/spec/runtime/document_spec.cc
@@ -69,8 +69,8 @@ describe("Document", [&]() {
     it("allows the input to be retrieved later", [&]() {
       ts_document_set_input(doc, spy_input->input());
       AssertThat(ts_document_input(doc).payload, Equals<void *>(spy_input));
-      AssertThat(ts_document_input(doc).read_fn, Equals(spy_input->input().read_fn));
-      AssertThat(ts_document_input(doc).seek_fn, Equals(spy_input->input().seek_fn));
+      AssertThat(ts_document_input(doc).read, Equals(spy_input->input().read));
+      AssertThat(ts_document_input(doc).seek, Equals(spy_input->input().seek));
     });
 
     it("does not assume that the document's text has changed", [&]() {
diff --git a/src/runtime/document.c b/src/runtime/document.c
index 0da347c1..1211eb5e 100644
--- a/src/runtime/document.c
+++ b/src/runtime/document.c
@@ -90,7 +90,7 @@ void ts_document_edit(TSDocument *self, TSInputEdit edit) {
 }
 
 int ts_document_parse(TSDocument *self) {
-  if (!self->input.read_fn || !self->parser.language)
+  if (!self->input.read || !self->parser.language)
     return -1;
 
   TSTree *reusable_tree = self->valid ? self->tree : NULL;
diff --git a/src/runtime/lexer.c b/src/runtime/lexer.c
index 7a3c2f04..d87ebd9c 100644
--- a/src/runtime/lexer.c
+++ b/src/runtime/lexer.c
@@ -24,11 +24,11 @@ static void ts_lexer__get_chunk(TSLexer *self) {
   TSInput input = self->input;
   if (!self->chunk ||
       self->current_position.bytes != self->chunk_start + self->chunk_size)
-    input.seek_fn(input.payload, self->current_position.chars,
+    input.seek(input.payload, self->current_position.chars,
                   self->current_position.bytes);
 
   self->chunk_start = self->current_position.bytes;
-  self->chunk = input.read_fn(input.payload, &self->chunk_size);
+  self->chunk = input.read(input.payload, &self->chunk_size);
   if (!self->chunk_size)
     self->chunk = empty_chunk;
 }
diff --git a/src/runtime/string_input.c b/src/runtime/string_input.c
index b1b87edc..338047c9 100644
--- a/src/runtime/string_input.c
+++ b/src/runtime/string_input.c
@@ -36,8 +36,8 @@ TSInput ts_string_input_make(const char *string) {
   input->length = strlen(string);
   return (TSInput){
     .payload = input,
-    .read_fn = ts_string_input_read,
-    .seek_fn = ts_string_input_seek,
+    .read = ts_string_input_read,
+    .seek = ts_string_input_seek,
     .encoding = TSInputEncodingUTF8,
   };