From bdf06c71433ea2155c0db78d309a0790bc83411c Mon Sep 17 00:00:00 2001
From: belhasse <rayan.belhassen@etu.u-paris.fr>
Date: Sat, 21 Mar 2026 13:27:12 +0100
Subject: [PATCH 1/2] escape data strings according to WebAssembly spec , Fixes
 #37

---
 src/ir/text.ml                  | 24 +++++++++++++++++++++++-
 test/fmt/data_bytes.wat         |  4 ++++
 test/fmt/data_roundtrip.t       |  8 ++++++++
 test/fmt/data_special_chars.wat |  4 ++++
 test/fmt/dune                   |  2 ++
 test/fmt/print.t                | 12 ++++++++++++
 6 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 test/fmt/data_bytes.wat
 create mode 100644 test/fmt/data_roundtrip.t
 create mode 100644 test/fmt/data_special_chars.wat

diff --git a/src/ir/text.ml b/src/ir/text.ml
index 2af9b75e0..67e8ffb10 100644
--- a/src/ir/text.ml
+++ b/src/ir/text.ml
@@ -16,6 +16,28 @@ type indice =
 
 let pp_id fmt id = pf fmt "$%s" id
 
+let pp_name_inner fmt s =
+  let pp_hex_char fmt c = pf fmt "\\%02x" (Char.code c) in
+  let pp_char fmt = function
+    | '\n' -> string fmt "\\n"
+    | '\r' -> string fmt "\\r"
+    | '\t' -> string fmt "\\t"
+    | '\'' -> string fmt "\\'"
+    | '"' -> string fmt "\\\""
+    | '\\' -> string fmt "\\\\"
+    | c ->
+      let ci = Char.code c in
+      if 0x20 <= ci && ci < 0x7f then char fmt c else pp_hex_char fmt c
+  in
+  let pp_unicode_char fmt = function
+    | (0x09 | 0x0a) as c -> pp_char fmt (Char.chr c)
+    | uc when 0x20 <= uc && uc < 0x7f -> pp_char fmt (Char.chr uc)
+    | uc -> pf fmt "\\u{%02x}" uc
+  in
+  String.iter (fun c -> pp_unicode_char fmt (Char.code c)) s
+
+let pp_name fmt s = pf fmt {|"%a"|} pp_name_inner s
+
 let pp_id_opt fmt = function None -> () | Some i -> pf fmt " %a" pp_id i
 
 let pp_indice fmt = function Raw u -> int fmt u | Text i -> pp_id fmt i
@@ -761,7 +783,7 @@ module Data = struct
     }
 
   let pp fmt (d : t) =
-    pf fmt {|(data%a %a %S)|} pp_id_opt d.id Mode.pp d.mode d.init
+    pf fmt {|(data%a %a %a)|} pp_id_opt d.id Mode.pp d.mode pp_name d.init
 end
 
 module Tag = struct
diff --git a/test/fmt/data_bytes.wat b/test/fmt/data_bytes.wat
new file mode 100644
index 000000000..0b61a1d7b
--- /dev/null
+++ b/test/fmt/data_bytes.wat
@@ -0,0 +1,4 @@
+(module
+  (memory 1)
+  (data (i32.const 0) "Hello\00World\01\02\03\ff")
+)
diff --git a/test/fmt/data_roundtrip.t b/test/fmt/data_roundtrip.t
new file mode 100644
index 000000000..4dda1361a
--- /dev/null
+++ b/test/fmt/data_roundtrip.t
@@ -0,0 +1,8 @@
+test data special chars round-trip:
+  $ owi fmt data_special_chars.wat > /tmp/owi_test_output.wat
+  $ owi fmt /tmp/owi_test_output.wat
+  (module
+    (memory 1)
+    (data (memory 0) (offset i32.const 0) "hello\n\t\u{0d}\"\'\\world")
+  )
+  $ rm /tmp/owi_test_output.wat
diff --git a/test/fmt/data_special_chars.wat b/test/fmt/data_special_chars.wat
new file mode 100644
index 000000000..0a0f8d4cc
--- /dev/null
+++ b/test/fmt/data_special_chars.wat
@@ -0,0 +1,4 @@
+(module
+  (memory 1)
+  (data (i32.const 0) "hello\n\t\r\"'\\world")
+)
diff --git a/test/fmt/dune b/test/fmt/dune
index 8c5d72d10..fe75cf4cf 100644
--- a/test/fmt/dune
+++ b/test/fmt/dune
@@ -11,5 +11,7 @@
   m.wat
   locals.wat
   locals_drop.wat
+  data_special_chars.wat
+  data_bytes.wat
   script.wast
   script.t))
diff --git a/test/fmt/print.t b/test/fmt/print.t
index c7c599387..42980de20 100644
--- a/test/fmt/print.t
+++ b/test/fmt/print.t
@@ -32,3 +32,15 @@ print simplified:
     )
     (start 1)
   )
+print data with special chars:
+  $ owi fmt data_special_chars.wat
+  (module
+    (memory 1)
+    (data (memory 0) (offset i32.const 0) "hello\n\t\u{0d}\"\'\\world")
+  )
+print data with raw bytes:
+  $ owi fmt data_bytes.wat
+  (module
+    (memory 1)
+    (data (memory 0) (offset i32.const 0) "Hello\u{00}World\u{01}\u{02}\u{03}\u{ff}")
+  )

From 5934e688b0dce1e14b3d097390e00b91a610ce7e Mon Sep 17 00:00:00 2001
From: belhasse <rayan.belhassen@etu.u-paris.fr>
Date: Tue, 24 Mar 2026 14:10:58 +0100
Subject: [PATCH 2/2] Address review comments for data string formatting

---
 src/ir/text.ml            | 12 +++++-------
 test/fmt/data_roundtrip.t |  6 +++---
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/ir/text.ml b/src/ir/text.ml
index 67e8ffb10..a2be1bd98 100644
--- a/src/ir/text.ml
+++ b/src/ir/text.ml
@@ -25,16 +25,14 @@ let pp_name_inner fmt s =
     | '\'' -> string fmt "\\'"
     | '"' -> string fmt "\\\""
     | '\\' -> string fmt "\\\\"
-    | c ->
-      let ci = Char.code c in
-      if 0x20 <= ci && ci < 0x7f then char fmt c else pp_hex_char fmt c
+    | '\x20' .. '\x7e' as c -> char fmt c
+    | c -> pp_hex_char fmt c
   in
   let pp_unicode_char fmt = function
-    | (0x09 | 0x0a) as c -> pp_char fmt (Char.chr c)
-    | uc when 0x20 <= uc && uc < 0x7f -> pp_char fmt (Char.chr uc)
-    | uc -> pf fmt "\\u{%02x}" uc
+    | ('\t' | '\n' | '\x20' .. '\x7e') as c -> pp_char fmt c
+    | c -> pf fmt "\\u{%02x}" (Char.code c)
   in
-  String.iter (fun c -> pp_unicode_char fmt (Char.code c)) s
+  String.iter (pp_unicode_char fmt) s
 
 let pp_name fmt s = pf fmt {|"%a"|} pp_name_inner s
 
diff --git a/test/fmt/data_roundtrip.t b/test/fmt/data_roundtrip.t
index 4dda1361a..df582ff58 100644
--- a/test/fmt/data_roundtrip.t
+++ b/test/fmt/data_roundtrip.t
@@ -1,8 +1,8 @@
 test data special chars round-trip:
-  $ owi fmt data_special_chars.wat > /tmp/owi_test_output.wat
-  $ owi fmt /tmp/owi_test_output.wat
+  $ owi fmt data_special_chars.wat > ./owi_test_output.wat
+  $ owi fmt ./owi_test_output.wat
   (module
     (memory 1)
     (data (memory 0) (offset i32.const 0) "hello\n\t\u{0d}\"\'\\world")
   )
-  $ rm /tmp/owi_test_output.wat
+  $ rm ./owi_test_output.wat