add pick op, increment version

SPEC.html

@@ -15,41 +15,6 @@
 	display: none;
 }
 
-/* From extension ms-toolsai.jupyter */
-/* These classnames are inherited from bootstrap, but are present in most notebook renderers */
-
-.alert {
-    width: auto;
-    padding: 1em;
-    margin-top: 1em;
-    margin-bottom: 1em;
-}
-.alert > *:last-child {
-    margin-bottom: 0;
-}
-#preview > .alert:last-child {
-    /* Prevent this being set to zero by the default notebook stylesheet */
-    padding-bottom: 1em;
-}
-
-.alert-success {
-    /* Note there is no suitable color available, so we just copy "info" */
-    background-color: var(--theme-info-background);
-    color: var(--theme-info-foreground);
-}
-.alert-info {
-    background-color: var(--theme-info-background);
-    color: var(--theme-info-foreground);
-}
-.alert-warning {
-    background-color: var(--theme-warning-background);
-    color: var(--theme-warning-foreground);
-}
-.alert-danger {
-    background-color: var(--theme-error-background);
-    color: var(--theme-error-foreground);
-}
-
 </style>
         
         <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/Microsoft/vscode/extensions/markdown-language-features/media/markdown.css">
@@ -408,11 +373,16 @@
 <p>Make a copy of the second item on top of the stack.</p>
 <p>The direct Klingon translation for <code>QI</code> is bridge, as in a bridge over a river, which works close enough.</p>
 <p>Errors: stackUnderflow</p>
-<h4 id="712-rotjir">7.1.2 rot/jIr</h4>
+<h4 id="712-pickwoh">7.1.2 pick/woH</h4>
+<p><em>N <code>woH</code> objN</em></p>
+<p>Make a copy of the Nth item on top of the stack.</p>
+<p>For example <em>1 <code>woH</code></em> is the same as <code>latlh</code> &amp; <em>2 <code>woH</code></em> is the same as <code>QI</code></p>
+<p>Errors: stackUnderflow, stackOverflow</p>
+<h4 id="713-rotjir">7.1.3 rot/jIr</h4>
 <p><em>obj1 obj2 obj3 <code>jIr</code> obj2 obj3 obj1</em></p>
 <p>Rotate the third item to the top of the stack.</p>
 <p>Errors: stackUnderflow</p>
-<h4 id="713-depthjuv">7.1.3 depth/juv</h4>
+<h4 id="714-depthjuv">7.1.4 depth/juv</h4>
 <p><em>- <code>juv</code> num</em></p>
 <p>Count the number of items on the stack and push that number to the top of the stack.</p>
 <p>Errors: stackUnderflow</p>

SPEC.md

@@ -1,5 +1,5 @@
 _var'aq_ Specification
-==================================
+=================================
 
 For better flavor text please read the [Original `var'aq` spec](https://www.oocities.org/connorbd/varaq/varaqspec.html) the following is a trimmed down version of the spec with a couple of fixes and addendums to how this implementation of the language works.
 
@@ -655,8 +655,17 @@ Make a copy of the second item on top of the stack.
 The direct Klingon translation for `QI` is bridge, as in a bridge over a river, which works close enough.
 
 Errors: stackUnderflow
+#### 7.1.2 pick/woH
 
-#### 7.1.2 rot/jIr
+_N `woH` objN_
+
+Make a copy of the Nth item on top of the stack.
+
+For example _1 `woH`_ is the same as `latlh` & _2 `woH`_ is the same as `QI`
+
+Errors: stackUnderflow, stackOverflow
+
+#### 7.1.3 rot/jIr
 
 _obj1 obj2 obj3 `jIr` obj2 obj3 obj1_
 
@@ -664,7 +673,7 @@ Rotate the third item to the top of the stack.
 
 Errors: stackUnderflow
 
-#### 7.1.3 depth/juv
+#### 7.1.4 depth/juv
 
 _- `juv` num_
 

examples/aoc2022/day1/p2.vqe

@@ -9,7 +9,7 @@
 } repeat
 
 elves shatter depth sub1 { 
-    over over lt? 
+    2 pick 2 pick lt? 
     choose
     { pop exch pop true } ifyes
     { pop } ifno

main.go

@@ -20,8 +20,8 @@ func main() {
 
 func repl() {
 	scanner := bufio.NewScanner(os.Stdin)
+	fmt.Print("> ")
 	for scanner.Scan() {
-		fmt.Print("> ")
 		line := scanner.Text()
 		if len(line) == 0 {
 			return
@@ -30,6 +30,7 @@ func repl() {
 		if err != nil {
 			fmt.Printf("%v\n", err)
 		}
+		fmt.Print("> ")
 	}
 }
 

varaq/interpreter.go

@@ -170,6 +170,33 @@ func Interpret(code Expr, argv []string) error {
 
 			push(stack[n-2])
 			stack = append(stack[:n-2], stack[n-3:]...)
+		case PICK:
+			n := len(stack) - 1
+			a, e := pop()
+			if e != nil {
+				return e
+			}
+			if a.Tok == IDENTIFIER {
+				a = get(a.Value.(string))
+			}
+
+			if a.Tok == NUMBER {
+				idx := int(a.Value.(float64))
+
+				if idx <= 0 {
+					return fmt.Errorf("`pick`: index must be a positive nonzero value")
+				}
+				if n-idx < 0 {
+					return fmt.Errorf("`pick`: stack underflow")
+				}
+				if idx > n {
+					return fmt.Errorf("`pick`: stack overflow")
+				}
+				push(stack[n-idx])
+			} else {
+				return fmt.Errorf("cannot `pick` index is not a number @%v", idx)
+			}
+
 		case DEPTH:
 			push(Expr{NUMBER, nil, float64(len(stack)), 0})
 		case CLEAR:
@@ -1232,7 +1259,7 @@ func Interpret(code Expr, argv []string) error {
 
 			fmt.Println(localAddr.IP.String())
 		case VERSION:
-			fmt.Println("var'aq -- 0.9.0 Martoq")
+			fmt.Println("var'aq -- 0.9.1 Martoq")
 		case ARGV:
 			arg := Expr{LIST, make([]Expr, 0), nil, 0}
 			for _, v := range argv {

varaq/scanner.go

@@ -181,6 +181,8 @@ var keywords = map[string]TokenType{
 	"QI":    OVER,
 	"depth": DEPTH,
 	"juv":   DEPTH,
+	"pick":  PICK,
+	"woH":   PICK,
 }
 
 func isDigit(s string) bool {

varaq/token.go

@@ -105,6 +105,7 @@ const (
 	OVER
 	ROT
 	DEPTH
+	PICK
 )
 
 var tokens = [...]string{
@@ -209,6 +210,7 @@ var tokens = [...]string{
 	OVER:           "OVER",
 	ROT:            "ROT",
 	DEPTH:          "DEPTH",
+	PICK:           "PICK",
 }
 
 func (me TokenType) String() string {