added progn form

stdlib/control_flow.go

@@ -22,6 +22,17 @@ import (
     "gitlab.com/whom/shs/log"
 )
 
+/* eval N forms. return the last one
+ */
+func shs_progn(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+    var res *ast.Token
+    for iter := in; iter != nil; iter = iter.Next {
+        res = iter.Eval(ft, vt, false)
+    }
+
+    return res
+}
+
 /* return one evaluated form or another based on the boolean statement
  */
 func shs_if(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {