added string join method

stdlib/stdlib.go

@@ -143,6 +143,13 @@ func GenFuncTable() ast.FuncTable {
             Args:           -1,
         },
 
+        "join": &ast.Function{
+            Function:    Join,
+            Name:      "join",
+            TimesCalled:    0,
+            Args:           2,
+        },
+
         "split": &ast.Function{
             Function:   Split,
             Name:     "split",

stdlib/string.go

@@ -100,6 +100,50 @@ func Split(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
     return res
 }
 
+/* Takes two args, a delimiter and a list of strings
+ * Returns the list of strings concatenated together with the delimiter in between each element
+ * On error returns nil
+ *
+ * Example: (join ", " ("apple" "ananas" "pear")) -> "apple, ananas, pear"
+ */
+func Join(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+    in = in.Eval(ft, vt, false)
+    if in == nil || in.Next == nil {
+        log.Log(log.ERR,
+            "one or more arguments evaluated to nil",
+            "join")
+        return nil
+    }
+
+    delim := in
+    strs := in.Next
+    if delim.Tag != ast.STRING || strs.Tag != ast.LIST {
+        log.Log(log.ERR,
+            "first argument must be a string (delimiter) and second argument must be a list (strings)",
+            "join")
+        return nil
+    }
+
+    de := delim.Value()
+    res := ""
+    for i := strs.Expand(); i != nil; i = i.Next {
+        if i.Tag != ast.STRING {
+            log.Log(log.ERR,
+                "all items to be joined must be strings",
+                "join")
+            return nil
+        }
+
+        res += i.Value()
+        if i.Next != nil {
+            res += de
+        }
+    }
+
+    ret := &ast.Token{Tag: ast.STRING}
+    ret.Set(res)
+    return ret
+}
 
 /* Takes one arg, returns nil
  * Prints a string to stdout