Add support for hex numbers

SCRIPTING.md

@@ -5,15 +5,38 @@
 ```
 # Lines starting with a "#" are comments.
 print "Call functions like this."
-sleep 500
-print "Done!"
+
+# Store values in variables for easy reusability.
+timeToSleep = 500
+sleep timeToSleep
+
+print "That's all folks!"
+```
+
+## Values
+
+There are 2 kinds of values: strings and integers. Strings are values wrapped in quotes (`"`). Integers are bare numbers, which can be either in decimal or hexadecimal notation.
+
+```
+print "I am a string"
+vKeyPress 65   # Decimal
+vKeyPress 0x41 # Hexadecimal
+```
+
+## Variables
+
+Values can be stored in a variable. These variables can be passed to functions just like other values. Variable names can contain letters, numbers, and underscores. Note that they cannot begin with a number.
+
+```
+a = 0x41
+vKeyPress a
 ```
 
 ## Functions
 
 ### `print`
 
-Print zero or more a value to the output. All arguments are concatenated together with a space.
+Print zero or more a values to the output. All arguments are concatenated together with a space.
 
 ```
 print "A simple print."
@@ -34,7 +57,7 @@ Concatenate multiple 42 values 123
 Wait a number of milliseconds before resuming the script.
 
 ```
-# Sleep for 1 second:
+# Sleep for 1 second
 sleep 1000
 ```
 
@@ -43,8 +66,9 @@ sleep 1000
 Press, down, or up a virtual key. The list of virtual key codes can be found on: https://docs.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes
 
 ```
-vKeyPress 65 # Press a 
-vKeyDown  16 # Down shift
-vKeyPress 65 # Press a
-vKeyUp    16 # Up shift
+# Type "aA"
+vKeyPress 0x41 # Press a 
+vKeyDown  0x10 # Down shift
+vKeyPress 0x41 # Press a
+vKeyUp    0x10 # Up shift
 ```

example.txt

@@ -2,14 +2,14 @@
 print "Starting script..."
 sleep 10 # milliseconds
 
-msg = "Assignment"
-print msg
-
 t = 100
 sleep t
 
 # aA
-vKeyPress   65
-vKeyDown    16
-vKeyPress   65
-vKeyUp      16
+a = 0x41
+shift = 0x10
+vKeyPress   a
+vKeyDown    shift
+vKeyPress   a
+vKeyUp      shift
+vKeyPress   a

internal/lexer/lexFunctions.go

@@ -27,9 +27,7 @@ func lexBegin(l *lexer) lexFn {
 		l.emit(TokenIdentifier)
 		return lexBegin
 	case unicode.IsNumber(nextRune):
-		l.readWhile(unicode.IsNumber)
-		l.emit(TokenLiteralInt)
-		return lexBegin
+		return lexNumberLiteral
 	case nextRune == quote:
 		return lexStringLiteral
 	case nextRune == equals:
@@ -63,3 +61,19 @@ func lexStringLiteral(l *lexer) lexFn {
 	l.emit(TokenLiteralString)
 	return lexBegin
 }
+
+func lexNumberLiteral(l *lexer) lexFn {
+	// Leading number
+	l.readRune()
+
+	if l.peekRune() == hex {
+		l.readRune()
+		l.readWhile(unicode.IsNumber)
+		l.emit(TokenLiteralHex)
+	} else {
+		l.readWhile(unicode.IsNumber)
+		l.emit(TokenLiteralInt)
+	}
+
+	return lexBegin
+}

internal/lexer/tokens.go

@@ -37,6 +37,7 @@ const (
 	TokenIdentifier
 	TokenLiteralString
 	TokenLiteralInt
+	TokenLiteralHex
 	tokenValueEnd
 
 	TokenAssign
@@ -52,6 +53,7 @@ var tokenNames = map[TokenType]string{
 	TokenIdentifier:    "Identifier",
 	TokenLiteralString: "String",
 	TokenLiteralInt:    "Int",
+	TokenLiteralHex:    "Hex",
 
 	TokenAssign: "Assign",
 }
@@ -62,4 +64,5 @@ const (
 	newline      rune = '\n'
 	quote        rune = '"'
 	equals       rune = '='
+	hex          rune = 'x'
 )

internal/parser/parser.go

@@ -167,6 +167,12 @@ func (p *parser) parseValue() (runtime.Value, error) {
 			return nil, fmt.Errorf("invalid number value: %s", valueToken.Value)
 		}
 		return runtime.NewNumberValue(intVal), nil
+	case lexer.TokenLiteralHex:
+		intVal, err := strconv.ParseInt(valueToken.Value, 0, 0)
+		if err != nil {
+			return nil, fmt.Errorf("invalid number value: %s", valueToken.Value)
+		}
+		return runtime.NewNumberValue(int(intVal)), nil
 	case lexer.TokenIdentifier:
 		return runtime.NewVariableValue(valueToken.Value), nil
 	default: