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comparison demo/prose @ 407:345fcf91c806

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Rec demo
author Adam Chlipala <adamc@hcoop.net>
date Tue, 21 Oct 2008 17:34:20 -0400
parents a71600cac815
children de3b03e22447
comparison
equal deleted inserted replaced
406:a71600cac815 407:345fcf91c806
36 36
37 link.urp 37 link.urp
38 38
39 <p>In <tt>link.ur</tt>, we see how easy it is to link to another page. The Ur/Web compiler guarantees that all links are valid. We just write some Ur/Web code inside an "antiquote" in our XML, denoting a transaction that will produce the new page if the link is clicked.</p> 39 <p>In <tt>link.ur</tt>, we see how easy it is to link to another page. The Ur/Web compiler guarantees that all links are valid. We just write some Ur/Web code inside an "antiquote" in our XML, denoting a transaction that will produce the new page if the link is clicked.</p>
40 40
41 rec.urp
42
43 <p>Crafting webs of interlinked pages is easy, using recursion.</p>
44
41 form.urp 45 form.urp
42 46
43 <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> 47 <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>
44 48
45 <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> 49 <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>