Sterling Clover wrote:
HStringTemplate is a port of Terrence Parr’s lovely StringTemplate (http://www.stringtemplate.org) engine to Haskell.
Reading Terrence Parr describe StringTemplate, at http://www.stringtemplate.org/about.html is amusing:
The fact that StringTemplate does not allow such things as assignments (no side-effects) should make you suspicious of engines that do allow it.
and
Another distinctive StringTemplate language feature lacking in other engines is lazy-evaluation. StringTemplate's attributes are lazily evaluated in the sense that referencing attribute "a" does not actually invoke the data lookup mechanism until the template is asked to render itself to text. Lazy evaluation is surprising useful in both the web and code generation worlds because such order decoupling allows code to set attributes when it is convenient or efficient not necessarily before a template that references those attributes is create
and
Just so you know, I've never been a big fan of functional languages and I laughed really hard when I realized (while writing the academic paper) that I had implemented a functional language. The nature of the problem simply dictated a particular solution. We are generating sentences in an output language so we should use something akin to a grammar. Output grammars are inconvenient so tool builders created template engines. Restricted template engines that enforce the universally-agreed-upon goal of strict model-view separation also look remarkably like output grammars as I have shown. So, the very nature of the language generation problem dictates the solution: a template engine that is restricted to support a mutually-recursive set of templates with side-effect-free and order-independent attribute references.
-- Chris _______________________________________________ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
