added type casts

stdlib/arith.go

@@ -29,6 +29,27 @@ import (
 // perhaps we simply write out arithmetic routines that operate on the strings
 // then we need not worry about storage length.
 
+func num_cast(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    in = in.Eval(f, a, false)
+    if in.Tag != ast.STRING {
+        log.Log(log.ERR,
+            "only a string can successfully be cast to a number",
+            "number_cast")
+        return nil
+    }
+
+    if !ast.StrIsNumber(in.Value()) {
+        log.Log(log.ERR,
+            "string failed number cast",
+            "number_cast")
+        return nil
+    }
+
+    out := in.Copy()
+    out.Tag = ast.NUMBER
+    return out
+}
+
 func add(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
     var res float64