Core update: Add null coalesce feature to core language.

Author: gabordemooij

base.c

@@ -115,6 +115,18 @@ ctr_object* ctr_nil_to_string(ctr_object* myself, ctr_argument* argumentList) {
 	return ctr_build_string_from_cstring( CTR_DICT_NIL );
 }
 
+/**
+ * @def
+ * [ Nil ] else: [ Object ]
+ *
+ * @example
+ * ☞ x ≔ Nil.
+ * ✎ write: (x else: 123), stop.
+ */
+ctr_object* ctr_nil_else_set(ctr_object* myself, ctr_argument* argumentList) {
+	return argumentList->object;
+}
+
 /**
  * @def
  * [ Nil ] number

citrine.h

@@ -441,6 +441,7 @@ extern ctr_object* ctr_nil_is_nil(ctr_object* myself, ctr_argument* argumentList
 extern ctr_object* ctr_nil_to_string(ctr_object* myself, ctr_argument* argumentList);
 extern ctr_object* ctr_nil_to_number(ctr_object* myself, ctr_argument* argumentList);
 extern ctr_object* ctr_nil_to_boolean(ctr_object* myself, ctr_argument* argumentList);
+extern ctr_object* ctr_nil_else_set(ctr_object* myself, ctr_argument* argumentList);
 
 /**
  * Object Interface

tests/exp/xx2/test0372.exp

@@ -0,0 +1,3 @@
+1
+2
+3

tests/test-o-mat/Configuration

@@ -31,6 +31,6 @@
 ☞ one way languages ≔ List ← ‘hy’ ; ‘en’.
 
 ☞ variations ≔	memory management modes + languages.
-☞ number of tests ≔ 371.
+☞ number of tests ≔ 372.
 
 ☞ base path for tests ≔ ‘../../’.

tests/test0372.ctr

@@ -0,0 +1,6 @@
+‘SINGLE_LANGUAGE’.
+✎ write: (Nil else: 1), stop.
+✎ write: (Nil else: Nil, else: 2), stop.
+✎ write: (Nil else: Nil, else: Nil, else: 3), stop.
+
+

world.c

@@ -689,6 +689,7 @@ void ctr_initialize_world() {
 	ctr_internal_create_func( CtrStdNil, ctr_build_string_from_cstring( CTR_DICT_TONUMBER ), &ctr_nil_to_number );
 	ctr_internal_create_func( CtrStdNil, ctr_build_string_from_cstring( CTR_DICT_TOBOOL ), &ctr_nil_to_boolean );
 	ctr_internal_create_func( CtrStdNil, ctr_build_string_from_cstring( CTR_DICT_CODE ), &ctr_nil_to_string );
+	ctr_internal_create_func( CtrStdNil, ctr_build_string_from_cstring( CTR_DICT_ELSE ), &ctr_nil_else_set );
 	CtrStdNil->link = CtrStdObject;
 	CtrStdNil->info.sticky = 1;