The list operator '<<' (append) and '>>' (prepend) have been replaced

with the new operators '<+' and '+>' respectively.
'<<' and '>>' are now used only for left and right binary shit
respectively. Further, their priority has been increased moving them to
a higher priority than that of the assignment operator.

operator-binary.go

@@ -11,7 +11,7 @@ func newBinNotTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 1),
 		position: posPrefix,
-		priority: priBinary,
+		priority: priBinNot,
 		evalFunc: evalBinaryNot,
 	}
 }
@@ -39,7 +39,7 @@ func newBinAndTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priBinary,
+		priority: priBinAnd,
 		evalFunc: evalBinaryAnd,
 	}
 }
@@ -71,7 +71,7 @@ func newBinOrTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priBinary,
+		priority: priBinOr,
 		evalFunc: evalBinaryOr,
 	}
 }