Ezra's Research

Phil pointed out that this syntax doesn't do much different from what Links already does, where you can just embed a function call, using form fields as free variables.

I realized after talking to him that there's one thing this might allow, which is the treatment of multiple submit buttons in one form. Let's try an example where the search box has a "Search Species" button, to search some database of animal species, and a "Help" button to search a certain help database instead.

fun search_feature() {
    handle
       <form action="{handler}">
       <input name="search_term" />
       <input type="submit" name="submit" value="Search Species" />
       <input type="submit" name="submit" value="Help" />
       </form>
    with
      {submit="Search Species",search_term=term} -> species_search(term)
    | {submit="Help",search_term=term} -> search_help(term)

Here we're matching on specific values for the submit argument and both cases are binding the value of search_term to a variable.

With the other syntax, you could do this, but you'd have to write a glue function which does the pattern matching and dispatches to the right handler function. So, call it sugar, but call it nice sugar. . .