From 84e358b971d73ad7c12e4b796ac15bdfa6c226b8 Mon Sep 17 00:00:00 2001
From: Cuihtlauac ALVARADO <cuihtlauac@tarides.com>
Date: Wed, 21 Oct 2026 08:57:48 +0200
Subject: [PATCH] graphql_parser: drop the `re` dependency

`re` was pulled into `graphql_parser` only for a handful of
single-character/newline operations, forcing a full regex engine onto
every downstream package.

- `block_string.ml`: replace `Re.split` (split on \r\n, \n, \r) with a
  hand-rolled `split_lines` that scans the string directly, mirroring
  the existing `get_block_string_indentation` logic.
- `ast.ml`: replace the chain of `Re.replace_string` calls in
  `quote_string` with a single-pass buffer escape.
- Drop `re` from `graphql_parser/src/dune` and `graphql_parser.opam`.

Closes #221

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 CHANGES.md                         |  5 +++++
 graphql_parser.opam                |  1 -
 graphql_parser/src/ast.ml          | 23 ++++++++++++++---------
 graphql_parser/src/block_string.ml | 26 ++++++++++++++++++--------
 graphql_parser/src/dune            |  2 +-
 5 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index b14c576..4b2127a 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,8 @@
+Unreleased
+---------------------------------
+
+- Drop the `re` dependency from `graphql_parser` (#221)
+
 0.14.0 2022-07-08
 ---------------------------------
 
diff --git a/graphql_parser.opam b/graphql_parser.opam
index 872916c..26b6501 100644
--- a/graphql_parser.opam
+++ b/graphql_parser.opam
@@ -17,7 +17,6 @@ depends: [
   "menhir" {build}
   "alcotest" {with-test & >= "0.8.1"}
   "fmt"
-  "re" {>= "1.5.0"}
 ]
 
 synopsis: "Library for parsing GraphQL queries"
diff --git a/graphql_parser/src/ast.ml b/graphql_parser/src/ast.ml
index ae41a9c..e593ef2 100644
--- a/graphql_parser/src/ast.ml
+++ b/graphql_parser/src/ast.ml
@@ -77,15 +77,20 @@ module Pp = struct
   let colon : unit Fmt.t = Fmt.(const string ":")
 
   let quote_string s =
-    let open Re in
-    s
-    |> replace_string (compile (char '\\')) ~by:"\\\\"
-    |> replace_string (compile (char '"')) ~by:"\\\""
-    |> replace_string (compile (char '\b')) ~by:"\\b"
-    |> replace_string (compile (char '\012')) ~by:"\\f"
-    |> replace_string (compile (char '\n')) ~by:"\\n"
-    |> replace_string (compile (char '\r')) ~by:"\\r"
-    |> replace_string (compile (char '\t')) ~by:"\\t"
+    let b = Buffer.create (String.length s) in
+    String.iter
+      (fun c ->
+        match c with
+        | '\\' -> Buffer.add_string b "\\\\"
+        | '"' -> Buffer.add_string b "\\\""
+        | '\b' -> Buffer.add_string b "\\b"
+        | '\012' -> Buffer.add_string b "\\f"
+        | '\n' -> Buffer.add_string b "\\n"
+        | '\r' -> Buffer.add_string b "\\r"
+        | '\t' -> Buffer.add_string b "\\t"
+        | c -> Buffer.add_char b c)
+      s;
+    Buffer.contents b
 
   let rec pp_value fmt = function
     | `Null -> Fmt.string fmt "null"
diff --git a/graphql_parser/src/block_string.ml b/graphql_parser/src/block_string.ml
index 797cd7b..e1fdddb 100644
--- a/graphql_parser/src/block_string.ml
+++ b/graphql_parser/src/block_string.ml
@@ -24,6 +24,23 @@ let get_block_string_indentation (s : string) : int =
   done;
   match !common_indent with None -> 0 | Some num -> num
 
+let split_lines (s : string) : string list =
+  let lines = ref [] in
+  let b = Buffer.create 32 in
+  let i = ref 0 in
+  let n = String.length s in
+  while !i < n do
+    ( match s.[!i] with
+    | ('\r' as c) | ('\n' as c) ->
+        if c == '\r' && try s.[!i + 1] == '\n' with _ -> false then incr i;
+        lines := Buffer.contents b :: !lines;
+        Buffer.clear b
+    | c -> Buffer.add_char b c );
+    incr i
+  done;
+  lines := Buffer.contents b :: !lines;
+  List.rev !lines
+
 exception NotBlank
 
 let is_blank (s : string) : bool =
@@ -33,14 +50,7 @@ let is_blank (s : string) : bool =
   with NotBlank -> false
 
 let dedent_block_string_value (s : string) : string =
-  let lines =
-    (let open Re in
-    split
-      (compile
-         (alt [ seq [ char '\r'; char '\n' ]; alt [ char '\n'; char '\r' ] ]))
-      s)
-    |> Array.of_list
-  in
+  let lines = split_lines s |> Array.of_list in
   let start_line = ref 0 in
   while !start_line < Array.length lines && is_blank lines.(!start_line) do
     incr start_line
diff --git a/graphql_parser/src/dune b/graphql_parser/src/dune
index 478fd7f..f29f07a 100644
--- a/graphql_parser/src/dune
+++ b/graphql_parser/src/dune
@@ -7,6 +7,6 @@
 (library
  (name graphql_parser)
  (public_name graphql_parser)
- (libraries fmt re)
+ (libraries fmt)
  (flags
   (:standard -w -30)))