feat(library): add experimental string ASC overloads

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

3 files changed, 19 insertions, 0 deletions

diff --git a/pseudocode-lib/README.md b/pseudocode-lib/README.md
index bd646ee..665e2ed 100644
--- a/pseudocode-lib/README.md
+++ b/pseudocode-lib/README.md
@@ -28,3 +28,5 @@ The library provides `&`, `_EXP_STRING_NUM_TO_STR` (INTEGER/REAL), `_EXP_STRING_
 `_EXP_STRING_LCASE(S : _EXP_STRING)` returns a new `_EXP_STRING` with letters converted to lower case. Its `(Ch : CHAR)` overload returns CHAR, following guide section 5.5. Nonletters and embedded NUL bytes are preserved; the source is unchanged. Use ASCII for predictable case conversion.
 
 `_EXP_STRING_UCASE(S : _EXP_STRING)` returns a new `_EXP_STRING` with letters converted to upper case. Its `(Ch : CHAR)` overload returns CHAR, following guide section 5.5. Nonletters and embedded NUL bytes are preserved; the source is unchanged. Use ASCII for predictable case conversion.
+
+`_EXP_STRING_ASC(S : _EXP_STRING)` returns the unsigned code of the first byte as INTEGER, or 0 for an empty string. Its `(Ch : CHAR)` overload returns the unsigned byte code of Ch. For ASCII characters this is the ASCII code.
diff --git a/pseudocode-lib/_exp_string.cc b/pseudocode-lib/_exp_string.cc
index bd476b8..6a17f74 100644
--- a/pseudocode-lib/_exp_string.cc
+++ b/pseudocode-lib/_exp_string.cc
@@ -113,6 +113,15 @@ char _exp_string_impl_ucase_char(char Ch) {
         return static_cast<char>(std::toupper(static_cast<unsigned char>(Ch)));
     });
 }
+long long _exp_string_impl_asc(void *Handle) {
+    return checked([&]() -> long long {
+        const auto &Source = text(Handle);
+        return Source.empty() ? 0 : static_cast<unsigned char>(Source.front());
+    });
+}
+long long _exp_string_impl_asc_char(char Ch) {
+    return checked([&]() -> long long { return static_cast<unsigned char>(Ch); });
+}
 void _exp_string_impl_output(void *Handle) {
     checked([&] {
         const auto &Text = text(Handle);
diff --git a/pseudocode-lib/_exp_string.cps b/pseudocode-lib/_exp_string.cps
index a56ed04..a4d95d6 100644
--- a/pseudocode-lib/_exp_string.cps
+++ b/pseudocode-lib/_exp_string.cps
@@ -21,6 +21,8 @@ EXTERN "C" EXTERN_PROCEDURE _exp_string_impl_lcase(_EXP_STRING_HANDLE, _EXP_STRI
 EXTERN "C" EXTERN_FUNCTION _exp_string_impl_lcase_char(C_CHAR) RETURNS C_CHAR
 EXTERN "C" EXTERN_PROCEDURE _exp_string_impl_ucase(_EXP_STRING_HANDLE, _EXP_STRING_HANDLE)
 EXTERN "C" EXTERN_FUNCTION _exp_string_impl_ucase_char(C_CHAR) RETURNS C_CHAR
+EXTERN "C" EXTERN_FUNCTION _exp_string_impl_asc(_EXP_STRING_HANDLE) RETURNS _EXP_STRING_C_INTEGER
+EXTERN "C" EXTERN_FUNCTION _exp_string_impl_asc_char(C_CHAR) RETURNS _EXP_STRING_C_INTEGER
 EXTERN "C" EXTERN_PROCEDURE _exp_string_impl_output(_EXP_STRING_HANDLE)
 
 CLASS _EXP_STRING
@@ -103,3 +105,9 @@ ENDFUNCTION
 OVERLOAD FUNCTION _EXP_STRING_UCASE(Ch : CHAR) RETURNS CHAR
     RETURN (CHAR)_exp_string_impl_ucase_char((C_CHAR)Ch)
 ENDFUNCTION
+OVERLOAD FUNCTION _EXP_STRING_ASC(S : _EXP_STRING) RETURNS INTEGER
+    RETURN (INTEGER)_exp_string_impl_asc(S._HANDLE)
+ENDFUNCTION
+OVERLOAD FUNCTION _EXP_STRING_ASC(Ch : CHAR) RETURNS INTEGER
+    RETURN (INTEGER)_exp_string_impl_asc_char((C_CHAR)Ch)
+ENDFUNCTION