# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1487612919 -3600
# Node ID 8325575e2d240b528ef4c4380c7c53665f407f5b
# Parent  b12c85bb0a4ca52b15afa26dfba10eefcf094e1e
Implemented the unichr function.

diff -r b12c85bb0a4c -r 8325575e2d24 lib/__builtins__/character.py
--- a/lib/__builtins__/character.py	Mon Feb 20 12:59:17 2017 +0100
+++ b/lib/__builtins__/character.py	Mon Feb 20 18:48:39 2017 +0100
@@ -20,7 +20,7 @@
 """
 
 from __builtins__.types import check_int, check_string
-from native import str_chr
+from native import str_chr, unicode_unichr
 
 def chr(i):
 
@@ -87,6 +87,15 @@
 
     return c.__ord__()
 
-def unichr(i): pass
+def unichr(i):
+
+    "Return the given character value 'i' encoded as a character."
+
+    check_int(i)
+
+    if 0 <= i <= 2097151:
+        return utf8string(unicode_unichr(i.__data__))
+    else:
+        raise ValueError, i
 
 # vim: tabstop=4 expandtab shiftwidth=4
diff -r b12c85bb0a4c -r 8325575e2d24 lib/native/__init__.py
--- a/lib/native/__init__.py	Mon Feb 20 12:59:17 2017 +0100
+++ b/lib/native/__init__.py	Mon Feb 20 18:48:39 2017 +0100
@@ -47,6 +47,6 @@
 
 from native.system import exit, get_argv, get_path
 
-from native.unicode import unicode_len, unicode_ord, unicode_substr
+from native.unicode import unicode_len, unicode_ord, unicode_substr, unicode_unichr
 
 # vim: tabstop=4 expandtab shiftwidth=4
diff -r b12c85bb0a4c -r 8325575e2d24 lib/native/unicode.py
--- a/lib/native/unicode.py	Mon Feb 20 12:59:17 2017 +0100
+++ b/lib/native/unicode.py	Mon Feb 20 18:48:39 2017 +0100
@@ -29,5 +29,6 @@
 def unicode_len(data): pass
 def unicode_ord(data): pass
 def unicode_substr(data, start, end, step): pass
+def unicode_unichr(value): pass
 
 # vim: tabstop=4 expandtab shiftwidth=4
diff -r b12c85bb0a4c -r 8325575e2d24 templates/native/unicode.c
--- a/templates/native/unicode.c	Mon Feb 20 12:59:17 2017 +0100
+++ b/templates/native/unicode.c	Mon Feb 20 18:48:39 2017 +0100
@@ -1,6 +1,6 @@
 /* Native functions for Unicode operations.
 
-Copyright (C) 2016 Paul Boddie <paul@boddie.org.uk>
+Copyright (C) 2016, 2017 Paul Boddie <paul@boddie.org.uk>
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -193,6 +193,48 @@
     return __new_str(sub, resultsize);
 }
 
+__attr __fn_native_unicode_unicode_unichr(__attr __args[])
+{
+    __attr * const value = &__args[1];
+    /* value interpreted as int */
+    int i = value->intvalue;
+    unsigned int resultsize;
+    char *s;
+
+    if (i < 128) resultsize = 1;
+    else if (i < 2048) resultsize = 2;
+    else if (i < 65536) resultsize = 3;
+    else resultsize = 4;
+
+    /* Reserve space for a new string. */
+
+    s = (char *) __ALLOCATE(resultsize + 1, sizeof(char));
+
+    /* Populate the string. */
+
+    if (i < 128) s[0] = (char) i;
+    else if (i < 2048)
+    {
+        s[0] = 0b11000000 | (i >> 6);
+        s[1] = 0b10000000 | (i & 0b00111111);
+    }
+    else if (i < 65536)
+    {
+        s[0] = 0b11100000 | (i >> 12);
+        s[1] = 0b10000000 | ((i >> 6) & 0b00111111);
+        s[2] = 0b10000000 | (i & 0b00111111);
+    }
+    else
+    {
+        s[0] = 0b11110000 | (i >> 18);
+        s[1] = 0b10000000 | ((i >> 12) & 0b00111111);
+        s[2] = 0b10000000 | ((i >> 6) & 0b00111111);
+        s[3] = 0b10000000 | (i & 0b00111111);
+    }
+
+    return __new_str(s, resultsize);
+}
+
 /* Module initialisation. */
 
 void __main_native_unicode()
diff -r b12c85bb0a4c -r 8325575e2d24 templates/native/unicode.h
--- a/templates/native/unicode.h	Mon Feb 20 12:59:17 2017 +0100
+++ b/templates/native/unicode.h	Mon Feb 20 18:48:39 2017 +0100
@@ -24,6 +24,7 @@
 __attr __fn_native_unicode_unicode_len(__attr __args[]);
 __attr __fn_native_unicode_unicode_ord(__attr __args[]);
 __attr __fn_native_unicode_unicode_substr(__attr __args[]);
+__attr __fn_native_unicode_unicode_unichr(__attr __args[]);
 
 /* Module initialisation. */
 
diff -r b12c85bb0a4c -r 8325575e2d24 tests/unicode.py
--- a/tests/unicode.py	Mon Feb 20 12:59:17 2017 +0100
+++ b/tests/unicode.py	Mon Feb 20 18:48:39 2017 +0100
@@ -212,3 +212,5 @@
 print repr(euro)                    # "\u20ac"
 print ord(euro)                     # 8364
 print "\u20ac"                      # ¤
+print unichr(ord(euro))             # ¤
+print unichr(ord(euro)) == euro     # True