X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fprelude.js;h=92144360cd23e13267ba29a8e135853655b60875;hb=ce86ba5f70b9e35bfb795402913f417de493e23f;hp=433462b5f5cf3fd30d51ebb80cfcd5d4b1abec17;hpb=99514b5a5f79348d9c619cce2bed562ce9082d4f;p=jscl.git

diff --git a/src/prelude.js b/src/prelude.js
index 433462b..9214436 100644
--- a/src/prelude.js
+++ b/src/prelude.js
@@ -4,6 +4,8 @@
 var window = this;
 var nil;
 
+var lisp = {};
+
 globalEval = eval;  // Just an indirect eval
 
 function pv (x) { return x==undefined? nil: x; }
@@ -51,14 +53,57 @@ function QIList(){
     }
 }
 
+// Return a new Array of strings, each either length-1, or length-2 (a UTF-16 surrogate pair).
+function codepoints(string) {
+    return string.split(/(?![\udc00-\udfff])/);
+}
 
 // Create and return a lisp string for the Javascript string STRING.
 function make_lisp_string (string){
-    var array = string.split("");
-    array.stringp = 1;
+    var array = codepoints(string);
+    array.stringp = 1
     return array;
 }
 
+function char_to_codepoint(ch) {
+    if (ch.length == 1) {
+        return ch.charCodeAt(0);
+    } else {
+        var xh = ch.charCodeAt(0) - 0xD800;
+        var xl = ch.charCodeAt(1) - 0xDC00;
+        return 0x10000 + (xh << 10) + (xl);
+    }
+}
+
+function char_from_codepoint(x) {
+    if (x <= 0xFFFF) {
+        return String.fromCharCode(x);
+    } else {
+        x -= 0x10000;
+        var xh = x >> 10;
+        var xl = x & 0x3FF;
+        return String.fromCharCode(0xD800 + xh) + String.fromCharCode(0xDC00 + xl);
+    }
+}
+
+// if a char (JS string) has the same number of codepoints after .toUpperCase(), return that, else the original.
+function safe_char_upcase(x) {
+    var xu = x.toUpperCase();
+    if (codepoints(xu).length == 1) {
+        return xu;
+    } else {
+        return x;
+    }
+}
+function safe_char_downcase(x) {
+    var xl = x.toLowerCase();
+    if (codepoints(xl).length == 1) {
+        return xl;
+    } else {
+        return x;
+    }
+}
+
 function xstring(x){ return x.join(''); }