diff options
| author |  Adam Chlipala <adamc@hcoop.net> | 2008-10-23 11:59:48 -0400 |
|---|---|---|
| committer | Adam Chlipala <adamc@hcoop.net> | 2008-10-23 11:59:48 -0400 |
| commit | 833f4d2e0474ec3ff772107b52711289c4b648cf (patch) | |
| tree | 9623809c43673edac7f48bb26d0be992f2c4377d /demo | |
| parent | e0f9a9d921e6e505c86ef3e798690784f7abd511 (diff) | |
Counter demo
Diffstat (limited to 'demo')
| -rw-r--r-- | demo/counter.ur | 7 | ||||
| -rw-r--r-- | demo/counter.urp | 2 | ||||
| -rw-r--r-- | demo/counter.urs | 1 | ||||
| -rw-r--r-- | demo/prose | 8 |
4 files changed, 16 insertions, 2 deletions
diff --git a/demo/counter.ur b/demo/counter.ur new file mode 100644 index 00000000..b11fc936 --- /dev/null +++ b/demo/counter.ur @@ -0,0 +1,7 @@ +fun counter n = return <xml><body> + Current counter: {[n]}<br/> + <a link={counter (n + 1)}>Increment</a><br/> + <a link={counter (n - 1)}>Decrement</a> +</body></xml> + +fun main () = counter 0 diff --git a/demo/counter.urp b/demo/counter.urp new file mode 100644 index 00000000..d22312c9 --- /dev/null +++ b/demo/counter.urp @@ -0,0 +1,2 @@ + +counter diff --git a/demo/counter.urs b/demo/counter.urs new file mode 100644 index 00000000..6ac44e0b --- /dev/null +++ b/demo/counter.urs @@ -0,0 +1 @@ +val main : unit -> transaction page @@ -44,12 +44,16 @@ rec.urp <p>Crafting webs of interlinked pages is easy, using recursion.</p> +counter.urp + +<p>It is also easy to pass state around via functions, in the style commonly associated with "continuation-based" web servers. As is usual for such systems, all state is stored on the client side. In this case, it is encoded in URLs.</p> + +<p>In the implementation of <tt>Counter.counter</tt>, we see the notation <tt>{[...]}</tt>, which uses type classes to inject values of different types (<tt>int</tt> in this case) into XML. It's probably worth stating explicitly that XML fragments <i>are not strings</i>, so that the type-checker will enforce that our final piece of XML is valid.</p> + form.urp <p>Here we see a basic form. The type system tracks which form inputs we include, and it enforces that the form handler function expects a record containing exactly those fields, with exactly the proper types.</p> -<p>In the implementation of <tt>handler</tt>, we see the notation <tt>{[...]}</tt>, which uses type classes to inject values of different types (<tt>string</tt> and <tt>bool</tt> in this case) into XML. It's probably worth stating explicitly that XML fragments <i>are not strings</i>, so that the type-checker will enforce that our final piece of XML is valid.</p> - listShop.urp <p>This example shows off algebraic datatypes, parametric polymorphism, and functors.</p> |