Implemented unary operator parsing

src/build/expression/Operator.go

@@ -10,7 +10,7 @@ import (
 type Operator struct {
 	Symbol     string
 	Precedence int8
-	Operands   int
+	Operands   int8
 }
 
 // Operators defines the operators used in the language.
@@ -19,6 +19,7 @@ var Operators = map[token.Kind]*Operator{
 	token.Period: {".", 13, 2},
 	token.Call:   {"λ", 12, 1},
 	token.Array:  {"@", 12, 2},
+	token.Negate: {"-", 11, 1},
 	token.Not:    {"!", 11, 1},
 	token.Mul:    {"*", 10, 2},
 	token.Div:    {"/", 10, 2},
@@ -73,7 +74,7 @@ func numOperands(symbol token.Kind) int {
 		return -1
 	}
 
-	return operator.Operands
+	return int(operator.Operands)
 }
 
 func precedence(symbol token.Kind) int8 {