From 518d2612e6c225933f0eb7b91a7b828455eac594 Mon Sep 17 00:00:00 2001
From: Steven Janzou <steven@janzouconsulting.com>
Date: Fri, 21 Mar 2025 02:07:33 -0600
Subject: [PATCH 1/2] Update isdigit, isalpha, and isalnum to handle Unicode
 characters

---
 src/stdlib.cpp | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/src/stdlib.cpp b/src/stdlib.cpp
index 1e8fdc1..3852fe2 100644
--- a/src/stdlib.cpp
+++ b/src/stdlib.cpp
@@ -1862,19 +1862,49 @@ static void _ascii(lk::invoke_t &cxt) {
 static void _isalpha(lk::invoke_t &cxt) {
     LK_DOC("isalpha", "Returns true if the argument is an alphabetic character A-Z,a-z.", "(character):boolean");
     lk_string s = cxt.arg(0).as_string();
-    cxt.result().assign(::isalpha(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
+    double x = 0;
+    try {
+        lk_char y = s[0];
+        if (y<256)
+            x = ::isalpha(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
+    }
+    catch (const std::exception&)  {
+        x = 0;
+    }
+    cxt.result().assign(x);
+    //cxt.result().assign(::isalpha(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
 }
 
 static void _isdigit(lk::invoke_t &cxt) {
     LK_DOC("isdigit", "Returns true if the argument is a numeric digit 0-9.", "(character):boolean");
     lk_string s = cxt.arg(0).as_string();
-    cxt.result().assign(::isdigit(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
+    double x = 0;
+    try {
+        lk_char y = s[0];
+        if (y < 256)
+            x = ::isdigit(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
+    }
+    catch (const std::exception&) {
+        x = 0;
+    }
+    cxt.result().assign(x);
+//    cxt.result().assign(::isdigit(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
 }
 
 static void _isalnum(lk::invoke_t &cxt) {
     LK_DOC("isalnum", "Returns true if the argument is an alphanumeric A-Z,a-z,0-9.", "(character):boolean");
     lk_string s = cxt.arg(0).as_string();
-    cxt.result().assign(::isalnum(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
+    double x = 0;
+    try {
+        lk_char y = s[0];
+        if (y < 256)
+            x = ::isalnum(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
+    }
+    catch (const std::exception&) {
+        x = 0;
+    }
+    cxt.result().assign(x);
+ //   cxt.result().assign(::isalnum(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
 }
 
 static void _char(lk::invoke_t &cxt) {

From 447dafacbc9a4ec662364c9d6b48d02b15fbae55 Mon Sep 17 00:00:00 2001
From: Paul Gilman <cpaulgilman@gmail.com>
Date: Fri, 21 Mar 2025 11:16:13 -0700
Subject: [PATCH 2/2] Fix isdigit, isalpha, isalnum to handle null character

---
 src/stdlib.cpp | 50 ++++++++++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/src/stdlib.cpp b/src/stdlib.cpp
index 3852fe2..109bc20 100644
--- a/src/stdlib.cpp
+++ b/src/stdlib.cpp
@@ -1863,13 +1863,15 @@ static void _isalpha(lk::invoke_t &cxt) {
     LK_DOC("isalpha", "Returns true if the argument is an alphabetic character A-Z,a-z.", "(character):boolean");
     lk_string s = cxt.arg(0).as_string();
     double x = 0;
-    try {
-        lk_char y = s[0];
-        if (y<256)
-            x = ::isalpha(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
-    }
-    catch (const std::exception&)  {
-        x = 0;
+    if (!s.IsNull()) {
+        try {
+            lk_char y = s[0];
+            if (y < 256 && !s.IsNull())
+                x = ::isalpha(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
+        }
+        catch (const std::exception&) {
+            x = 0;
+        }
     }
     cxt.result().assign(x);
     //cxt.result().assign(::isalpha(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
@@ -1879,29 +1881,33 @@ static void _isdigit(lk::invoke_t &cxt) {
     LK_DOC("isdigit", "Returns true if the argument is a numeric digit 0-9.", "(character):boolean");
     lk_string s = cxt.arg(0).as_string();
     double x = 0;
-    try {
-        lk_char y = s[0];
-        if (y < 256)
-            x = ::isdigit(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
-    }
-    catch (const std::exception&) {
-        x = 0;
+    if (!s.IsNull()) {
+        try {
+            lk_char y = s[0];
+            if (y < 256)
+                x = ::isdigit(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
+        }
+        catch (const std::exception&) {
+            x = 0;
+        }
     }
     cxt.result().assign(x);
 //    cxt.result().assign(::isdigit(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);
 }
 
-static void _isalnum(lk::invoke_t &cxt) {
+static void _isalnum(lk::invoke_t& cxt) {
     LK_DOC("isalnum", "Returns true if the argument is an alphanumeric A-Z,a-z,0-9.", "(character):boolean");
     lk_string s = cxt.arg(0).as_string();
     double x = 0;
-    try {
-        lk_char y = s[0];
-        if (y < 256)
-            x = ::isalnum(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
-    }
-    catch (const std::exception&) {
-        x = 0;
+    if (!s.IsNull()) {
+        try {
+            lk_char y = s[0];
+            if (y < 256)
+                x = ::isalnum(s.length() > 0 ? (int)y : 0) ? 1.0 : 0.0;
+        }
+        catch (const std::exception&) {
+            x = 0;
+        }
     }
     cxt.result().assign(x);
  //   cxt.result().assign(::isalnum(s.length() > 0 ? (int) s[0] : 0) ? 1.0 : 0.0);