Compiling Expressions 17

src/common/util.d

@@ -8,6 +8,37 @@ template defaultCtor(){
 }
 
 import std.ascii : isAlpha, isAlphaNum;
-bool isAlpha_(dchar c)    => c.isAlpha    || c == '_';
-bool isAlphaNum_(dchar c) => c.isAlphaNum || c == '_';
+bool isAlpha_(dchar c)    @nogc nothrow @safe => c.isAlpha    || c == '_';
+bool isAlphaNum_(dchar c) @nogc nothrow @safe => c.isAlphaNum || c == '_';
+
+T pop(T)(ref T[] arr){
+	T v = arr.last;
+	arr.length--;
+	return v;
+}
+T shift(T)(ref T[] arr){
+	T v = arr.first;
+	arr = arr[1 .. $];
+	return v;
+}
+ref T sole(T)(T[] arr) @nogc @safe pure{
+	assert(arr.length == 1, "Not sole");
+	return arr[0];
+}
+ref T first(T)(T[] arr) @nogc @safe pure{
+	assert(arr.length >= 1, "No first");
+	return arr[0];
+}
+ref T second(T)(T[] arr) @nogc @safe pure{
+	assert(arr.length >= 2, "No second");
+	return arr[1];
+}
+ref T third(T)(T[] arr) @nogc @safe pure{
+	assert(arr.length >= 3, "No third");
+	return arr[2];
+}
+ref T last(T)(T[] arr) @nogc @safe pure{
+	assert(arr.length >= 1, "No last");
+	return arr[$-1];
+}